Merge branch 'dev' - dynamic winding width

Due to color changes of linked parts all files got changed
(meaning no actual modifications to parts was made)

.gitattributes

@@ -0,0 +1 @@
+*.fcstd text

.gitignore

@@ -1,6 +1,29 @@
 # ESP-IDF default build directory
 build
+sdkconfig.old
+dependencies.lock
 
 # VIM files
 *.swp
 *.swo
+**/.cache
+
+# VS-code
+settings.json
+
+# drawio files
+*.bkp
+
+# freecad backup files
+*.FCStd1
+*.FCBak
+# stl files are usually temporary
+*.stl
+
+# kicad backup files
+pcb/*/*backups/
+
+# other
+octave-workspace
+del
+screenshots

CMakeLists.txt

@@ -6,4 +6,4 @@ cmake_minimum_required(VERSION 3.5)
 
 #set(EXTRA_COMPONENT_DIRS ../esp-idf-lib/components)
 include($ENV{IDF_PATH}/tools/cmake/project.cmake)
-project(cable-length-cutting)
+project(cable-length-cutter)

README.md

@@ -0,0 +1,94 @@
+# Overview
+Firmware and documentation of a custom built machine that winds and cuts cable to certain lengths.  
+Extensive details about this project can be found on the website: [pfusch.zone/cable-length-cutter](https://pfusch.zone/cable-length-cutter)
+
+<img src="img/cable-length-cutter.jpg" alt="Photo machine" style="width:60%;">
+
+Photo of the built machine
+
+## Current Features
+- Measure length using rotary encoder
+- Wind to set length while start-button is pressed
+- Automatic wire cutter
+- Control interface:
+  - 2x 7-Segment display showing lengths and notifications
+  - Buzzer for acoustic notifications
+  - 4 Buttons and Potentiometer for setting the target length
+  - Reset and Cut Button
+- Stepper motor controlling a linear axis guiding the cable while winding
+- Store last axis position at shutdown
+
+
+# Usage
+![Panel Layout](img/panel-layout.svg)
+
+
+# Electrical Details
+For detailed documentation of all electrical aspects, see [connection-plan.pdf](connection-plan.pdf).
+
+
+# Printed Parts
+All designed and 3D-printed parts can be found in the [cad/](cad/) folder. These parts were designed using FreeCAD.
+
+
+# Components
+### Custom pcb with ESP-32 microcontroller
+See [connection-plan.pdf](connection-plan.pdf)  
+
+### Rotary encoder LPD3806-600BM-G5-24C
+```
+- Pulses: 600 p/r (Single-phase 600 pulses /R,Two phase 4 frequency doubling to 2400 pulses)
+- Power source: DC5-24V
+- Shaft: 6*13mm/0.23*0.51"
+- Size: 38*35.5mm/1.49*1.39"
+- Output :AB 2phase output rectangular orthogonal pulse circuit, the output for the NPN open collector output type
+- Maximum mechanical speed: 5000 R / min
+- Response frequency: 0-20KHz
+- Cable length: 1.5 meter
+- size: http://domoticx.com/wp-content/uploads/2020/05/LPD3806-afmetingen.jpg
+- Wires: Green = A phase, white = B phase, red = Vcc power +, black = V0
+```
+### Variable Frequency Drive T13-400W-12-H
+See [docs/vfd/](docs/vfd/)
+
+### Stepper-driver TB6600
+See [docs/stepper-driver_TB6600-Manual.pdf](docs/stepper-driver_TB6600-Manual.pdf)
+
+### Linear Axis with Nema-12 28HB40 Stepper
+See [connection-plan.pdf](connection-plan.pdf)  
+
+
+
+
+# Installation
+For this project **ESP-IDF v4.4.4** is required (with other versions it might not compile)
+```bash
+#download esp-idf
+yay -S esp-idf 
+#alternatively clone the esp-idf repository from github and do `git checkout release/4.4`
+
+#run installation script in installed folder
+/opt/esp-idf/install.sh
+```
+
+# Build
+### Set up environment
+```bash
+source /opt/esp-idf/export.sh
+```
+(run once per terminal)
+
+### Compile
+```bash
+cd board_single
+idf.py build
+```
+
+# Flash
+- connect FTDI programmer to board (VCC to VCC; TX to RX; RX to TX)
+- press REST and BOOT button
+- release RESET button (keep pressing boot)
+- run flash command:
+```bash
+idf.py flash
+```

cad/export/.gitignore

@@ -0,0 +1,4 @@
+# Ignore everything in this directory
+*
+# Except this file
+!.gitignore

components/DendoStepper/CMakeLists.txt

@@ -0,0 +1 @@
+idf_component_register(SRCS DendoStepper.cpp INCLUDE_DIRS include)

components/DendoStepper/DendoStepper.cpp

@@ -0,0 +1,413 @@
+#include "DendoStepper.h"
+#include "esp_log.h"
+
+#define STEP_DEBUG
+
+#ifdef STEP_DEBUG
+#define STEP_LOGI(...) ESP_LOGI(__VA_ARGS__)
+#define STEP_LOGW(...) ESP_LOGW(__VA_ARGS__)
+#define STEP_LOGE(...) ESP_LOGE(__VA_ARGS__)
+#else
+#define STEP_LOGI(...) while (0)
+#define STEP_LOGW(...) while (0)
+#define STEP_LOGE(...) ESP_LOGE(__VA_ARGS__)
+#endif
+
+bool state = 0;
+
+// PUBLIC definitions
+
+DendoStepper::DendoStepper()
+{
+}
+
+void DendoStepper::config(DendoStepper_config_t *config)
+{
+    memcpy(&conf, config, sizeof(conf));
+}
+
+void DendoStepper::disableMotor()
+{
+    setEn(true);
+    STEP_LOGI("DendoStepper", "Disabled");
+    ctrl.status = DISABLED;
+}
+
+void DendoStepper::enableMotor()
+{
+    setEn(false);
+    ctrl.status = IDLE;
+    STEP_LOGI("DendoStepper", "Enabled");
+    timerStarted = 0;
+}
+
+void DendoStepper::init(uint8_t stepP, uint8_t dirP, uint8_t enP, timer_group_t group, timer_idx_t index, microStepping_t microstepping = MICROSTEP_1, uint16_t stepsPerRot = 200)
+{
+    conf.stepPin = stepP;
+    conf.dirPin = dirP;
+    conf.enPin = enP;
+    conf.timer_group = group;
+    conf.timer_idx = index;
+    conf.miStep = microstepping;
+    ctrl.status = 0;
+    init();
+}
+
+void DendoStepper::init()
+{
+    uint64_t mask = (1ULL << conf.stepPin) | (1ULL << conf.dirPin) | (1ULL << conf.enPin); // put output gpio pins in bitmask
+    gpio_config_t gpio_conf = {
+        // config gpios
+        .pin_bit_mask = mask,
+        .mode = GPIO_MODE_OUTPUT,
+        .pull_up_en = GPIO_PULLUP_DISABLE,
+        .pull_down_en = GPIO_PULLDOWN_DISABLE,
+        .intr_type = GPIO_INTR_DISABLE,
+    };
+    // set the gpios as per gpio_conf
+    ESP_ERROR_CHECK(gpio_config(&gpio_conf));
+
+    timer_config_t timer_conf = {
+        .alarm_en = TIMER_ALARM_EN,         // we need alarm
+        .counter_en = TIMER_PAUSE,          // dont start now lol
+        .intr_type = TIMER_INTR_LEVEL,      // interrupt
+        .counter_dir = TIMER_COUNT_UP,      // count up duh
+        .auto_reload = TIMER_AUTORELOAD_EN, // reload pls
+        .divider = 80000000ULL / TIMER_F,   // ns resolution
+    };
+
+    // calculate stepsPerRot
+    ctrl.stepsPerRot = (360.0 / conf.stepAngle) * conf.miStep;
+
+    STEP_LOGI("DendoStepper", "Steps per one rotation:%d", ctrl.stepsPerRot);
+
+    if (conf.timer_group != TIMER_GROUP_MAX && conf.timer_idx != TIMER_MAX)
+    {
+        // timer was configured explixitly in config structure, we dont need to do it here
+        goto timer_avail;
+    }
+
+    // try to find free timer
+    timer_config_t temp;
+    for (int i = 0; i < 1; i++)
+    {
+        for (int j = 0; j < 1; j++)
+        {
+            timer_get_config((timer_group_t)i, (timer_idx_t)j, &temp);
+            if (temp.alarm_en == TIMER_ALARM_DIS)
+            {
+                // if the alarm is disabled, chances are no other dendostepper instance is using it
+                conf.timer_group = (timer_group_t)i;
+                conf.timer_idx = (timer_idx_t)j;
+                goto timer_avail;
+            }
+        }
+    }
+
+    // if we got here it means that there isnt any free timer available
+    STEP_LOGE("DendoStepper", "No free timer available, this stepper wont work");
+    return;
+
+timer_avail:
+    ESP_ERROR_CHECK(timer_init(conf.timer_group, conf.timer_idx, &timer_conf));                   // init the timer
+    ESP_ERROR_CHECK(timer_set_counter_value(conf.timer_group, conf.timer_idx, 0));                // set it to 0
+    ESP_ERROR_CHECK(timer_isr_callback_add(conf.timer_group, conf.timer_idx, xISRwrap, this, 0)); // add callback fn to run when alarm is triggrd
+}
+
+esp_err_t DendoStepper::runPos(int32_t relative)
+{
+    //TODO only enable when actually moving
+    if (ctrl.status == DISABLED) // if motor is disabled, enable it
+        enableMotor();
+
+    if (!relative) // why would u call it with 0 wtf
+        return ESP_ERR_NOT_SUPPORTED;
+
+    if (ctrl.status > IDLE) { //currently moving
+        bool newDir = (relative < 0); // CCW if <0, else set CW
+        if (ctrl.dir == newDir){ //current direction is the same
+            ctrl.statusPrev = ctrl.status; //update previous status
+            ctrl.status = ctrl.status==COAST ? COAST : ACC; //stay at coast otherwise switch to ACC
+            calc(abs(relative + ctrl.stepsRemaining)); //calculate new velolcity profile for new+remaining steps
+        } else { //direction has changed
+                 //direction change not supported TODO wait for decel finish / queue?
+            STEP_LOGW("DendoStepper", "DIRECTION HOT-CHANGE NOT SUPPORTED - Finising previous move, this command will be ignored");
+            return ESP_ERR_NOT_SUPPORTED;
+        }
+    }
+    else { //current state is IDLE
+        ctrl.statusPrev = ctrl.status; //update previous status
+        ctrl.status = ACC;
+        setDir(relative < 0); // set CCW if <0, else set CW
+        calc(abs(relative));                                                                         // calculate velocity profile
+    }
+
+    currentPos += relative; //(target position / not actual)
+    ESP_ERROR_CHECK(timer_set_alarm_value(conf.timer_group, conf.timer_idx, ctrl.stepInterval)); // set HW timer alarm to stepinterval
+                                                                                                 //TODO timer has to be stopped before update if already running?
+    ESP_ERROR_CHECK(timer_start(conf.timer_group, conf.timer_idx));                              // start the timer
+
+    return ESP_OK;
+}
+
+esp_err_t DendoStepper::runPosMm(int32_t relative)
+{
+    if (ctrl.stepsPerMm == 0)
+    {
+        STEP_LOGE("DendoStepper", "Steps per millimeter not set, cannot move!");
+    }
+    return runPos(relative * ctrl.stepsPerMm);
+}
+
+esp_err_t DendoStepper::runAbs(uint32_t position)
+{
+    if (getState() > IDLE) // we are already moving, so stop it
+        stop();
+    while (getState() > IDLE)
+    {
+        // waiting for idle, watchdog should take care of inf loop if it occurs
+        vTaskDelay(1);
+    } // shouldnt take long tho
+
+    if (position == currentPos) // we cant go anywhere
+        return 0;
+
+    int32_t relativeSteps = 0;
+    relativeSteps = (int32_t)position - currentPos;
+
+    ESP_LOGI("DendoStepper", "Cur: %llu move %d", currentPos, relativeSteps);
+    return runPos(relativeSteps); // run to new position
+}
+
+esp_err_t DendoStepper::runAbsMm(uint32_t position)
+{
+    if (ctrl.stepsPerMm == 0)
+    {
+        STEP_LOGE("DendoStepper", "Steps per millimeter not set, cannot move!");
+    }
+    return runAbs(position * ctrl.stepsPerMm);
+}
+
+void DendoStepper::setSpeed(uint32_t speed, uint16_t accT, uint16_t decT)
+{
+    ctrl.speed = speed;
+    ctrl.acc = ctrl.speed / (accT / 4000.0);
+    ctrl.dec = ctrl.speed / (decT / 4000.0);
+    STEP_LOGI("DendoStepper", "Speed set: %d steps/s t+=%d s t-=%d s", speed, accT, decT);
+}
+
+void DendoStepper::setSpeedMm(uint32_t speed, uint16_t accT, uint16_t decT)
+{
+    if (ctrl.stepsPerMm == 0)
+    {
+        STEP_LOGE("DendoStepper", "Steps per millimeter not set, cannot set the speed!");
+    }
+    ctrl.speed = speed * ctrl.stepsPerMm;
+
+    ctrl.acc = ctrl.speed / (accT / 4000.0);
+    ctrl.dec = ctrl.speed / (decT / 4000.0);
+    STEP_LOGI("DendoStepper", "Speed set: v=%d mm/s t+=%d s t-=%d s", speed, accT, decT);
+}
+
+//CUSTOM - change speed while running 
+//FIXME: this approach does not work, since calc function would have to be run after change, this will mess up target steps...
+//void DendoStepper::changeSpeed(uint32_t speed)
+//{
+//    //TODO reduce duplicate code (e.g. call setSpeed function)
+//    //change speed
+//    ctrl.speed = speed;
+//    //change status to ACC/DEC
+//    STEP_LOGI("DendoStepper", "Speed changed: from v=%.2f rad/s to v=%.2f rad/s", ctrl.speed, speed);
+//    if (speed > ctrl.speed) ctrl.status = ACC;
+//    if (speed < ctrl.speed) ctrl.status = DEC;
+//}
+//
+//void DendoStepper::changeSpeedMm(uint32_t speed)
+//{
+//    //TODO reduce duplicate code (e.g. call setSpeedMm function)
+//    if (ctrl.stepsPerMm == 0)
+//    {
+//        STEP_LOGE("DendoStepper", "Steps per millimeter not set, cannot set the speed!");
+//    }
+//    //calc new speed
+//    float speedNew = speed * ctrl.stepsPerMm;
+//    //change status to ACC/DEC
+//    if (speedNew > ctl.speed) ctrl.status = ACC;
+//    if (speedNew < ctl.speed) ctrl.status = DEC;
+//    //update speed, log output
+//    ctrl.speed = speedNew;
+//    STEP_LOGI("DendoStepper", "Speed changed: from v=%.2f rad/s to v=%.2f rad/s", ctrl.speed, speedNew);
+//}
+
+
+void DendoStepper::setStepsPerMm(uint16_t steps)
+{
+    ctrl.stepsPerMm = steps;
+}
+
+uint16_t DendoStepper::getStepsPerMm()
+{
+    return ctrl.stepsPerMm;
+}
+
+uint8_t DendoStepper::getState()
+{
+    return ctrl.status;
+}
+
+uint64_t DendoStepper::getPosition()
+{
+    return currentPos;
+}
+
+uint64_t DendoStepper::getPositionMm()
+{
+    return getPosition() / ctrl.stepsPerMm;
+}
+
+void DendoStepper::resetAbsolute()
+{
+    currentPos = 0;
+}
+
+void DendoStepper::runInf(bool direction)
+{
+    if (ctrl.status > IDLE)
+    {
+        STEP_LOGE("DendoStepper", "Motor is moving, this command will be ignored");
+        return;
+    }
+    if (ctrl.status == DISABLED)
+    {
+        enableMotor();
+    }
+    ctrl.runInfinite = true;
+    setDir(direction);
+    calc(UINT32_MAX);
+    ESP_ERROR_CHECK(timer_set_alarm_value(conf.timer_group, conf.timer_idx, ctrl.stepInterval)); // set HW timer alarm to stepinterval
+    ESP_ERROR_CHECK(timer_start(conf.timer_group, conf.timer_idx));                              // start the timer
+}
+
+uint16_t DendoStepper::getSpeed()
+{
+    return ctrl.speed;
+}
+
+float DendoStepper::getAcc()
+{
+    return ctrl.acc;
+}
+
+void DendoStepper::stop()
+{
+    if (ctrl.status <= IDLE)
+    {
+        return;
+    }
+    ctrl.runInfinite = false;
+    timer_pause(conf.timer_group, conf.timer_idx); // stop the timer
+    ctrl.statusPrev = ctrl.status; //update previous status
+    ctrl.status = IDLE;
+    ctrl.stepCnt = 0;
+    gpio_set_level((gpio_num_t)conf.stepPin, 0);
+}
+
+// PRIVATE definitions
+
+void DendoStepper::setEn(bool state)
+{
+    ESP_ERROR_CHECK(gpio_set_level((gpio_num_t)conf.enPin, state));
+}
+
+void DendoStepper::setDir(bool state)
+{
+    ctrl.dir = state;
+    ESP_ERROR_CHECK(gpio_set_level((gpio_num_t)conf.dirPin, state));
+}
+
+/* Timer callback, used for generating pulses and calculating speed profile in real time */
+bool DendoStepper::xISR()
+{
+    GPIO.out_w1ts = (1ULL << conf.stepPin);
+    // add and substract one step
+
+    ctrl.stepCnt++;
+
+    //CUSTOM: track actual precice current position
+    if (ctrl.dir) {
+        ctrl.posActual ++;
+    } else {
+        ctrl.posActual --;
+    }
+    //CUSTOM: track remaining steps for eventually resuming
+    ctrl.stepsRemaining = ctrl.stepCnt - ctrl.stepCnt; 
+
+    // we are done
+    if (ctrl.stepsToGo == ctrl.stepCnt && !ctrl.runInfinite)
+    {
+        timer_pause(conf.timer_group, conf.timer_idx); // stop the timer
+        ctrl.statusPrev = ctrl.status; //update previous status
+        ctrl.status = IDLE;
+        ctrl.stepCnt = 0;
+        return 0;
+    }
+
+    if (ctrl.stepCnt > 0 && ctrl.stepCnt < ctrl.accEnd)
+    { // we are accelerating
+        ctrl.currentSpeed += ctrl.accInc;
+        ctrl.statusPrev = ctrl.status; //update previous status
+        ctrl.status = ACC; // we are accelerating, note that*/
+    }
+    else if (ctrl.stepCnt > ctrl.coastEnd && !ctrl.runInfinite)
+    { // we must be deccelerating then
+        ctrl.currentSpeed -= ctrl.decInc;
+        ctrl.statusPrev = ctrl.status; //update previous status
+        ctrl.status = DEC; // we are deccelerating
+    }
+    else
+    {
+        ctrl.currentSpeed = ctrl.targetSpeed;
+        ctrl.statusPrev = ctrl.status; //update previous status
+        ctrl.status = COAST; // we are coasting
+    }
+
+    ctrl.stepInterval = TIMER_F / ctrl.currentSpeed;
+    // set alarm to calculated interval and disable pin
+    GPIO.out_w1tc = (1ULL << conf.stepPin);
+    timer_set_alarm_value(conf.timer_group, conf.timer_idx, ctrl.stepInterval);
+    ctrl.stepCnt++;
+    return 1;
+}
+
+void DendoStepper::calc(uint32_t targetSteps)
+{
+    //steps from ctrl.speed -> 0:
+    ctrl.decSteps = 0.5 * ctrl.dec * (ctrl.speed / ctrl.dec) * (ctrl.speed / ctrl.dec);
+    //steps from 0 -> ctrl.speed:
+    //ctrl.accSteps = 0.5 * ctrl.acc * (ctrl.speed / ctrl.acc) * (ctrl.speed / ctrl.acc);
+    //steps from ctrl.currentSpeed -> ctrl.speed:
+    ctrl.accSteps = 0.5 * ctrl.acc * (ctrl.speed / ctrl.acc) * (ctrl.speed / ctrl.acc)  * (ctrl.speed - ctrl.currentSpeed) / ctrl.speed;
+
+    if (targetSteps < (ctrl.decSteps + ctrl.accSteps))
+    {
+        ESP_LOGI("Dendostepper", "Computing new speed");
+
+        ctrl.speed = sqrt(2 * targetSteps * ((ctrl.dec * ctrl.acc) / (ctrl.dec + ctrl.acc)));
+        ctrl.accSteps = 0.5 * ctrl.acc * (ctrl.speed / ctrl.acc) * (ctrl.speed / ctrl.acc);
+        ctrl.decSteps = 0.5 * ctrl.dec * (ctrl.speed / ctrl.dec) * (ctrl.speed / ctrl.dec);
+    }
+
+    ctrl.accEnd = ctrl.accSteps;
+    ctrl.coastEnd = targetSteps - ctrl.decSteps;
+    ctrl.targetSpeed = ctrl.speed;
+
+    ctrl.accInc = ctrl.targetSpeed / (double)ctrl.accSteps;
+    ctrl.decInc = ctrl.targetSpeed / (double)ctrl.decSteps;
+
+    ctrl.currentSpeed = ctrl.accInc;
+
+    ctrl.stepInterval = TIMER_F / ctrl.currentSpeed;
+    ctrl.stepsToGo = targetSteps;
+
+    STEP_LOGI("calc", "acc end:%u coastend:%u stepstogo:%u speed:%f acc:%f int: %u", ctrl.accEnd, ctrl.coastEnd, ctrl.stepsToGo, ctrl.speed, ctrl.acc, ctrl.stepInterval);
+}

components/DendoStepper/LICENSE

@@ -0,0 +1,674 @@
+                    GNU GENERAL PUBLIC LICENSE
+                       Version 3, 29 June 2007
+
+ Copyright (C) 2007 Free Software Foundation, Inc. <https://fsf.org/>
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+                            Preamble
+
+  The GNU General Public License is a free, copyleft license for
+software and other kinds of works.
+
+  The licenses for most software and other practical works are designed
+to take away your freedom to share and change the works.  By contrast,
+the GNU General Public License is intended to guarantee your freedom to
+share and change all versions of a program--to make sure it remains free
+software for all its users.  We, the Free Software Foundation, use the
+GNU General Public License for most of our software; it applies also to
+any other work released this way by its authors.  You can apply it to
+your programs, too.
+
+  When we speak of free software, we are referring to freedom, not
+price.  Our General Public Licenses are designed to make sure that you
+have the freedom to distribute copies of free software (and charge for
+them if you wish), that you receive source code or can get it if you
+want it, that you can change the software or use pieces of it in new
+free programs, and that you know you can do these things.
+
+  To protect your rights, we need to prevent others from denying you
+these rights or asking you to surrender the rights.  Therefore, you have
+certain responsibilities if you distribute copies of the software, or if
+you modify it: responsibilities to respect the freedom of others.
+
+  For example, if you distribute copies of such a program, whether
+gratis or for a fee, you must pass on to the recipients the same
+freedoms that you received.  You must make sure that they, too, receive
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+know their rights.
+
+  Developers that use the GNU GPL protect your rights with two steps:
+(1) assert copyright on the software, and (2) offer you this License
+giving you legal permission to copy, distribute and/or modify it.
+
+  For the developers' and authors' protection, the GPL clearly explains
+that there is no warranty for this free software.  For both users' and
+authors' sake, the GPL requires that modified versions be marked as
+changed, so that their problems will not be attributed erroneously to
+authors of previous versions.
+
+  Some devices are designed to deny users access to install or run
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+
+  Finally, every program is threatened constantly by software patents.
+States should not allow patents to restrict development and use of
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+avoid the special danger that patents applied to a free program could
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+patents cannot be used to render the program non-free.
+
+  The precise terms and conditions for copying, distribution and
+modification follow.
+
+                       TERMS AND CONDITIONS
+
+  0. Definitions.
+
+  "This License" refers to version 3 of the GNU General Public License.
+
+  "Copyright" also means copyright-like laws that apply to other kinds of
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+
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components/DendoStepper/README.md

@@ -0,0 +1,139 @@
+# DendoStepper
+
+Work in progress, maybe unstable. Opening issues is more than welcome.  
+This library takes care of pulse generating for stepper motor drivers with STEP/DIR interface. Pulse generating utilizes general purpose timers to achieve some usable accuracy and smoothness.  
+Currently supports only linear acceleration and deceleration.
+
+### Known limitations
+- maximum number of controlled stepper motors is 4, this is limited by number of general purpose timers
+- If the motor is moving, it is not possible to move it to another direction.
+
+## Usage
+
+```c++
+typedef struct
+{
+    uint8_t stepPin;           /** step signal pin */
+    uint8_t dirPin;            /** dir signal pin */
+    uint8_t enPin;             /** enable signal pin */
+    timer_group_t timer_group; /** timer group, useful if we are controlling more than 2 steppers */
+    timer_idx_t timer_idx;     /** timer index, useful if we are controlling 2steppers */
+    microStepping_t miStep;    /** microstepping configured on driver - used in distance calculation */
+    float stepAngle;           /** one step angle in degrees (usually 1.8deg), used in steps per rotation calculation */
+} DendoStepper_config_t;
+
+enum microStepping_t
+{
+    MICROSTEP_1 = 0x1,
+    MICROSTEP_2,
+    MICROSTEP_4 = 0x4,
+    MICROSTEP_8 = 0x8,
+    MICROSTEP_16 = 0x10,
+    MICROSTEP_32 = 0x20,
+    MICROSTEP_64 = 0x40,
+    MICROSTEP_128 = 0x80,
+    MICROSTEP_256 = 0x100,
+};
+
+```  
+Configuration struct, can be allocated on stack or heap.
+
+```c++
+void init();
+```  
+Initializes GPIO and Timer peripherals, registers ISR. Expects populated config struct is alreay passed to the class using config()  
+
+```c++
+void config(DendoStepper_config_t* config);
+```
+Configures the class as per passed config struct pointer.  
+
+```c++
+void setStepsPerMm(uint16_t steps);
+uint16_t getStepsPerMm();
+```
+Sets or gets steps needed to move one millimiter, useful if stepper is moving along linear axis.  
+
+```c++
+void setSpeed(uint16_t speed,uint16_t accT, uint16_t decT);
+uint16_t getSpeed();
+float getAcc();
+```
+Sets maximum speed in steps per second, acceleration and deceleration time in milliseconds.  
+Gets speed in steps per second  
+Gets acceleration in steps per second per second
+
+```c++
+void setSpeedMm(uint16_t speed,uint16_t accT, uint16_t decT);
+```
+Sets maximum speed in mm/s, acceleration and deceleration time in milliseconds. Expects already defined steps per millimeter with setStepsPerMm()  
+
+```c++
+void runPos(int32_t relative);
+```
+Runs motor to position relative from current position in steps, respecting constraints set with setSpeed()  
+
+```c++
+void runPosMm(int32_t relative);
+```
+Runs motor to position relative from current position in millimeters, respecting constraints set with setSpeed()  
+Expects already defined steps per millimeter with setStepsPerMm()  
+
+```c++
+ bool runAbsolute(uint32_t position);
+```
+Runs motor in absolute coordinate plane. Unit: steps (should be constrained with home switch)  
+
+```c++
+ bool runAbsoluteMm(uint32_t position);
+```
+Runs motor in absolute coordinate plane. Unit: millimeters (should be constrained with home switch)  
+Expects already defined steps per millimeter with setStepsPerMm()  
+
+```c++
+ bool runInf(bool direction);
+```
+Runs motor infintely in desired direction with constrains set using setSpeed().  
+
+```c++
+void disableMotor();
+void enableMotor();
+```
+Disables and enables motor via EN pin
+
+```c++
+uint8_t getState();
+
+enum motor_status{
+    DISABLED,
+    IDLE,
+    ACC,
+    COAST,
+    DEC,
+};
+```
+Returns current state of motor, return type is enum motor_status  
+
+
+```c++
+void resetAbsolute();
+```
+Resets absolute position to 0. Called for ex. when endswitch is hit.  
+
+```c++
+void getPosition();
+```
+Gets current position in absolute coordinate plane in steps.  
+
+```c++
+void getPositionMm();
+```
+Gets current position in absolute coordinate plane in millimeters.  
+Expects already defined steps per millimeter with setStepsPerMm()  
+
+```c++
+void stop();
+```
+Stops the motor dead on the spot. No deceleration is performed this way. Eg. e-stop.  
+
+

components/DendoStepper/example/.gitignore

@@ -0,0 +1,3 @@
+build/
+sdkconfig
+sdkconfig.old

components/DendoStepper/example/CMakeLists.txt

@@ -0,0 +1,9 @@
+# For more information about build system see
+# https://docs.espressif.com/projects/esp-idf/en/latest/api-guides/build-system.html
+# The following five lines of boilerplate have to be in your project's
+# CMakeLists in this exact order for cmake to work correctly
+cmake_minimum_required(VERSION 3.5)
+
+include($ENV{IDF_PATH}/tools/cmake/project.cmake)
+set(EXTRA_COMPONENT_DIRS "../")
+project(example)

components/DendoStepper/example/README.md

@@ -0,0 +1,32 @@
+# _Sample project_
+
+(See the README.md file in the upper level 'examples' directory for more information about examples.)
+
+This is the simplest buildable example. The example is used by command `idf.py create-project`
+that copies the project to user specified path and set it's name. For more information follow the [docs page](https://docs.espressif.com/projects/esp-idf/en/latest/api-guides/build-system.html#start-a-new-project)
+
+
+
+## How to use example
+We encourage the users to use the example as a template for the new projects.
+A recommended way is to follow the instructions on a [docs page](https://docs.espressif.com/projects/esp-idf/en/latest/api-guides/build-system.html#start-a-new-project).
+
+## Example folder contents
+
+The project **sample_project** contains one source file in C language [main.c](main/main.c). The file is located in folder [main](main).
+
+ESP-IDF projects are built using CMake. The project build configuration is contained in `CMakeLists.txt`
+files that provide set of directives and instructions describing the project's source files and targets
+(executable, library, or both). 
+
+Below is short explanation of remaining files in the project folder.
+
+```
+├── CMakeLists.txt
+├── main
+│   ├── CMakeLists.txt
+│   └── main.c
+└── README.md                  This is the file you are currently reading
+```
+Additionally, the sample project contains Makefile and component.mk files, used for the legacy Make based build system. 
+They are not used or needed when building with CMake and idf.py.

components/DendoStepper/example/main/CMakeLists.txt

@@ -0,0 +1,3 @@
+idf_component_register(SRCS "main.cpp"
+                    INCLUDE_DIRS "."
+                    REQUIRES DendoStepper freertos)

components/DendoStepper/example/main/main.cpp

@@ -0,0 +1,49 @@
+#include <stdio.h>
+#include "DendoStepper.h"
+#include "freertos/FreeRTOS.h"
+#include "freertos/task.h"
+#include "esp_log.h"
+
+DendoStepper step;
+DendoStepper step1;
+
+extern "C" void app_main(void)
+{
+    DendoStepper_config_t step_cfg = {
+        .stepPin = 16,
+        .dirPin = 17,
+        .enPin = 15,
+        .timer_group = TIMER_GROUP_0,
+        .timer_idx = TIMER_0,
+        .miStep = MICROSTEP_32,
+        .stepAngle = 1.8};
+
+    DendoStepper_config_t step1_cfg = {
+        .stepPin = 18,
+        .dirPin = 19,
+        .enPin = 20,
+        .timer_group = TIMER_GROUP_0,
+        .timer_idx = TIMER_1,
+        .miStep = MICROSTEP_32,
+        .stepAngle = 1.8};
+
+    step.config(&step_cfg);
+    step1.config(&step1_cfg);
+
+    step.init();
+    step1.init();
+
+    step.setSpeed(10000, 1000, 1000);
+    step1.setSpeed(20000, 1000, 1000);
+
+    // step.runInf(true);
+    step.setStepsPerMm(10);
+
+    while (1)
+    {
+        step.runPosMm(500);
+        step1.runPos(10000);
+        vTaskDelay(1000);
+        // step.runAbs(5000);
+    }
+}

components/DendoStepper/include/DendoStepper.h

@@ -0,0 +1,281 @@
+#pragma once
+
+/*  ESP-IDF library for bipolar stepper motor drivers with STEP/DIR interface
+    Copyright (C) 2022 Denis Voltmann
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+#ifndef DENDOSTEPPER_H
+#define DENDOSTEPPER_H
+
+#include "stdint.h"
+#include "stdio.h"
+#include <cstring>
+#include "driver/timer.h"
+#include "driver/gpio.h"
+#include "freertos/FreeRTOS.h"
+#include "freertos/task.h"
+#include "esp_timer.h"
+#include "math.h"
+
+//#define STEP_DEBUG
+
+#define NS_TO_T_TICKS(x) (x)
+#define TIMER_F 1000000ULL
+#define TICK_PER_S TIMER_F
+
+enum motor_status
+{
+    DISABLED,
+    IDLE,
+    ACC,
+    COAST,
+    DEC
+};
+
+enum dir
+{
+    CW,
+    CCW
+};
+
+enum microStepping_t
+{
+    MICROSTEP_1 = 0x1,
+    MICROSTEP_2,
+    MICROSTEP_4 = 0x4,
+    MICROSTEP_8 = 0x8,
+    MICROSTEP_16 = 0x10,
+    MICROSTEP_32 = 0x20,
+    MICROSTEP_64 = 0x40,
+    MICROSTEP_128 = 0x80,
+    MICROSTEP_256 = 0x100,
+};
+
+/**
+ * @brief Configuration structure
+ */
+typedef struct
+{
+    uint8_t stepPin;           /** step signal pin */
+    uint8_t dirPin;            /** dir signal pin */
+    uint8_t enPin;             /** enable signal pin */
+    timer_group_t timer_group; /** timer group, useful if we are controlling more than 2 steppers */
+    timer_idx_t timer_idx;     /** timer index, useful if we are controlling 2steppers */
+    microStepping_t miStep;    /** microstepping configured on driver - used in distance calculation */
+    float stepAngle;           /** one step angle in degrees (usually 1.8deg), used in steps per rotation calculation */
+} DendoStepper_config_t;
+
+typedef struct
+{
+    uint32_t stepInterval = 40000; // step interval in ns/25
+    double targetSpeed = 0;        // target speed in steps/s
+    double currentSpeed = 0;
+    double accInc = 0;
+    double decInc = 0;
+    uint32_t stepCnt = 0;   // step counter
+    uint32_t accEnd;        // when to end acc and start coast
+    uint32_t coastEnd;      // when to end coast and start decel
+    uint32_t stepsToGo = 0; // steps we need to take
+    float speed = 100;      // speed in rad/s
+    float acc = 100;        // acceleration in rad*second^-2
+    float dec = 100;        // decceleration in rad*second^-2
+    uint32_t accSteps = 0;
+    uint32_t decSteps = 0;
+    int32_t stepsRemaining = 0;
+    uint64_t posActual = 0; //actual current pos incremented at every step
+    uint8_t statusPrev = DISABLED; //FIXME currently unused
+    uint8_t status = DISABLED;
+    bool dir = CW;
+    bool runInfinite = false;
+    uint16_t stepsPerRot;    // steps per one revolution, 360/stepAngle * microstep
+    uint16_t stepsPerMm = 0; /** Steps per one milimiter, if the motor is performing linear movement */
+} ctrl_var_t;
+
+class DendoStepper
+{
+private:
+    DendoStepper_config_t conf;
+    ctrl_var_t ctrl;
+    esp_timer_handle_t dyingTimer;
+    TaskHandle_t enTask;
+    uint64_t currentPos = 0; // absolute position
+    bool timerStarted = 0;
+
+    /** @brief PRIVATE: Step interval calculation
+     *  @param speed maximum movement speed
+     *  @param accTimeMs acceleration time in ms
+     *  @param target target position
+     */
+    void calc(uint32_t);
+
+    /** @brief sets En GPIO
+     *  @param state 0-LOW,1-HIGH
+     *  @return void
+     */
+    void setEn(bool);
+
+    /** @brief sets Dir GPIO
+     *  @param state 0-CW 1-CCW
+     */
+    void setDir(bool);
+
+    /** @brief static wrapper for ISR function
+     *  @param _this DendoStepper* this pointer
+     *  @return bool
+     */
+    static bool xISRwrap(void *_this)
+    {
+        return static_cast<DendoStepper *>(_this)->xISR();
+    }
+
+    /** @brief enableMotor wrapper
+     */
+    static void _disableMotor(void *_this)
+    {
+        static_cast<DendoStepper *>(_this)->disableMotor();
+    }
+
+    bool xISR();
+
+public:
+    /** @brief Costructor - conf variables to be passed later
+     */
+    DendoStepper();
+
+    /** @brief Configuration of library, used with constructor w/o params
+     *  @param config DendoStepper_config_t structure pointer - can be freed after this call
+     */
+    void config(DendoStepper_config_t *config);
+
+    /** @brief initialize GPIO and Timer peripherals
+     *  @param stepP step pulse pin
+     *  @param dirP direction signal pin
+     *  @param enP enable signal Pin
+     *  @param group timer group to use (0 or 1)
+     *  @param index which timer to use (0 or 1)
+     *  @param microstepping microstepping performed by the driver, used for more accuracy
+     *  @param stepsPerRot how many steps it takes for the motor to move 2Pi rads. this can be also used instead of microstepping parameter
+     */
+    void init(uint8_t, uint8_t, uint8_t, timer_group_t, timer_idx_t, microStepping_t microstep, uint16_t stepsPerRot);
+
+    /** @brief initialize GPIO and Timer peripherals, class must be configured beforehand with @attention config()
+     */
+    void init();
+
+    /** @brief runs motor to relative position in steps
+     *  @param relative number of steps to run, negative is reverse
+     */
+    esp_err_t runPos(int32_t relative);
+
+    /** @brief runs motor to relative position in mm
+     *  @param relative number of mm to run, negative is reverse
+     */
+    esp_err_t runPosMm(int32_t relative);
+
+    /** @brief run motor to position in absolute coordinates (steps)
+     *  @param postition absolute position in steps from home position (must be positive);
+     *  @return ESP_OK if motor can run immediately, ESP_ERR if it is currently moving
+     */
+    esp_err_t runAbs(uint32_t position);
+
+    /** @brief run motor to position in absolute coordinates (millimiters)
+     *  @param postition absolute position in mm from home position (must be positive);
+     *  @return ESP_OK if motor can run immediately, ESP_ERR if it is currently moving
+     */
+    esp_err_t runAbsMm(uint32_t position);
+
+    /** @brief sets motor speed
+     *  @param speed speed in steps per second
+     *  @param accT acceleration time in ms
+     *  @param decT deceleration time in ms
+     */
+    void setSpeed(uint32_t speed, uint16_t accT, uint16_t decT);
+
+    /** @brief sets motor speed and accel in millimeters/second
+     *  @param speed speed mm*s^-1
+     *  @param accT acceleration time in ms
+     *  @param accT deceleration time in ms
+     */
+    void setSpeedMm(uint32_t speed, uint16_t accT, uint16_t decT);
+
+    //CUSTOM: change speed while running
+    void changeSpeedMm(uint32_t speed);
+
+    /**
+     * @brief Set steps per 1 mm of linear movement
+     *
+     * @param steps steps needed to move one millimiter
+     */
+    void setStepsPerMm(uint16_t steps);
+
+    /**
+     * @brief get steps per 1mm settings
+     *
+     */
+    uint16_t getStepsPerMm();
+
+    /** @brief set EN pin 1, stops movement
+     */
+    void disableMotor();
+
+    /** @brief set EN pin to 0, enables movement
+     */
+    void enableMotor();
+
+    /** @brief returns current state
+     *  @return motor_status enum
+     */
+    uint8_t getState();
+
+    /** @brief run motor to position in absolute coordinates (millimiters)
+     *  @param postition absolute position in steps from home position (must be positive);
+     *  @return ESP_OK if motor can run immediately, ESP_ERR if it is currently moving
+     */
+    esp_err_t runAbsoluteMm(uint32_t position);
+
+    /** @brief returns current absolute position
+     *  @return current absolute postion in steps
+     */
+    uint64_t getPosition();
+
+    /** @brief returns current absolute position
+     *  @return current absolute postion in steps
+     */
+    uint64_t getPositionMm();
+
+    /** @brief resets absolute pos to 0
+     */
+    void resetAbsolute();
+
+    /** @brief
+     *
+     */
+    void runInf(bool direction);
+
+    /** @brief returns current speed in steps per second
+     */
+    uint16_t getSpeed();
+
+    /** @brief returns current acceleration time in ms
+     */
+    float getAcc();
+
+    /** @brief stops the motor dead, but stays enabled
+     */
+    void stop();
+};
+
+#endif

components/gpio/CMakeLists.txt

@@ -0,0 +1,6 @@
+idf_component_register(
+    SRCS 
+        "gpio_evaluateSwitch.cpp"
+        "gpio_adc.cpp"
+    INCLUDE_DIRS "."
+)

components/gpio/gpio_adc.cpp

@@ -0,0 +1,21 @@
+#include "gpio_adc.hpp"
+
+
+//=============================
+//========= readAdc ===========
+//=============================
+//function for multisampling an anlog input
+int gpio_readAdc(adc1_channel_t adc_channel, bool inverted) {
+    //make multiple measurements
+    int adc_reading = 0;
+    for (int i = 0; i < 32; i++) {
+        adc_reading += adc1_get_raw(adc_channel);
+    }
+    adc_reading = adc_reading / 32;
+    //return original or inverted result
+    if (inverted) {
+        return 4095 - adc_reading;
+    } else {
+        return adc_reading;
+    }
+}

components/gpio/gpio_adc.hpp

@@ -0,0 +1,9 @@
+#pragma once
+#include <stdio.h>
+#include "driver/adc.h"
+
+//function for multisampling an anlog input
+//measures 30 times and returns average
+//if invertion is used currently 11bit resolution is assumed (subtracts from 4095) 
+//TODO: rework this function to be more universal
+int gpio_readAdc(adc1_channel_t adc_channel, bool inverted = false);

components/gpio/gpio_evaluateSwitch.cpp

@@ -0,0 +1,146 @@
+#include "gpio_evaluateSwitch.hpp"
+
+static const char *TAG = "evaluateSwitch";
+
+
+gpio_evaluatedSwitch::gpio_evaluatedSwitch( //minimal (use default values)
+        gpio_num_t gpio_num_declare
+        ){
+    gpio_num = gpio_num_declare;
+    pullup = true;
+    inverted = false;
+    inputSource = inputSource_t::GPIO;
+
+    initGpio();
+};
+
+
+gpio_evaluatedSwitch::gpio_evaluatedSwitch( //optional parameters given
+        gpio_num_t gpio_num_declare,
+        bool pullup_declare,
+        bool inverted_declare
+        ){
+    gpio_num = gpio_num_declare;
+    pullup = pullup_declare;
+    inverted = inverted_declare;
+    inputSource = inputSource_t::GPIO;
+
+    initGpio();
+};
+
+
+gpio_evaluatedSwitch::gpio_evaluatedSwitch( //with function as input source
+        bool (*getInputStatePtr_f)(void),
+        bool inverted_f){
+    //gpio_num = NULL;
+    //pullup = NULL;
+    inverted = inverted_f;
+    getInputStatePtr = getInputStatePtr_f;
+    inputSource = inputSource_t::FUNCTION;
+};
+
+
+
+void gpio_evaluatedSwitch::initGpio(){
+    ESP_LOGI(TAG, "initializing gpio pin %d", (int)gpio_num);
+
+    //define gpio pin as input
+    gpio_pad_select_gpio(gpio_num);
+    gpio_set_direction(gpio_num, GPIO_MODE_INPUT);
+
+    if (pullup == true){ //enable pullup if desired (default)
+        gpio_pad_select_gpio(gpio_num);
+        gpio_set_pull_mode(gpio_num, GPIO_PULLUP_ONLY);
+    }else{
+        gpio_set_pull_mode(gpio_num, GPIO_FLOATING);
+        gpio_pad_select_gpio(gpio_num);
+    }
+    //TODO add pulldown option
+    //gpio_set_pull_mode(gpio_num, GPIO_PULLDOWN_ONLY);
+};
+
+
+
+void gpio_evaluatedSwitch::handle(){  //Statemachine for debouncing and edge detection
+
+    //--- get pin state with required method ---
+    switch (inputSource){
+        case inputSource_t::GPIO: //from gpio pin
+            if (gpio_get_level(gpio_num) == 0){ //pin low
+                inputState = true;
+            } else { //pin high
+                inputState = false;
+            }
+            break;
+        case inputSource_t::FUNCTION: //from funtion
+            inputState = (*getInputStatePtr)();
+            break;
+    }
+
+    //--- invert state ---
+    //not inverted: switch switches to GND when active
+    //inverted: switch switched to VCC when active
+    if (inverted == true){
+        inputState = !inputState;
+    }
+
+
+    //=========================================================
+    //========= Statemachine for evaluateing switch ===========
+    //=========================================================
+    switch (p_state){
+        default:
+            p_state = switchState::FALSE;
+            break;
+
+        case switchState::FALSE:  //input confirmed high (released)
+            fallingEdge = false; //reset edge event
+            if (inputState == true){ //pin high (on)
+                p_state = switchState::HIGH;
+                timestampHigh = esp_log_timestamp(); //save timestamp switched from low to high
+            } else {
+                msReleased = esp_log_timestamp() - timestampLow; //update duration released
+            }
+            break;
+
+        case switchState::HIGH: //input recently switched to high (pressed)
+            if (inputState == true){ //pin still high (on)
+                if (esp_log_timestamp() - timestampHigh > minOnMs){ //pin in same state long enough
+                    p_state = switchState::TRUE;
+                    state = true;
+                    risingEdge = true;
+                    msReleased = timestampHigh - timestampLow; //calculate duration the button was released 
+                }
+            }else{
+                p_state = switchState::FALSE;
+            }
+            break;
+
+        case switchState::TRUE:  //input confirmed high (pressed)
+            risingEdge = false; //reset edge event
+            if (inputState == false){ //pin low (off)
+                timestampLow = esp_log_timestamp();
+                p_state = switchState::LOW;
+            } else {
+                msPressed = esp_log_timestamp() - timestampHigh; //update duration pressed
+            }
+
+            break;
+
+        case switchState::LOW: //input recently switched to low (released)
+            if (inputState == false){ //pin still low (off)
+                if (esp_log_timestamp() - timestampLow > minOffMs){ //pin in same state long enough
+                    p_state = switchState::FALSE;
+                    msPressed = timestampLow - timestampHigh; //calculate duration the button was pressed
+                    state=false;
+                    fallingEdge=true;
+                }
+            }else{
+                p_state = switchState::TRUE;
+            }
+            break;
+    }
+
+}
+
+

components/gpio/gpio_evaluateSwitch.hpp

@@ -0,0 +1,71 @@
+#pragma once
+
+#include <stdio.h>
+
+extern "C"
+{
+#include "freertos/FreeRTOS.h"
+#include "freertos/task.h"
+#include "driver/gpio.h"
+#include "esp_log.h"
+}
+
+//constructor examples:
+//switch to gnd and us internal pullup:
+//gpio_evaluatedSwitch s3(GPIO_NUM_14);
+//switch to gnd dont use internal pullup:
+//gpio_evaluatedSwitch s3(GPIO_NUM_14 false);
+//switch to VCC (inverted) and dont use internal pullup:
+//gpio_evaluatedSwitch s3(GPIO_NUM_14 false, true);
+
+enum class inputSource_t {GPIO, FUNCTION};
+
+class gpio_evaluatedSwitch {
+    public:
+        //--- input ---
+        uint32_t minOnMs = 30;
+        uint32_t minOffMs = 30;
+
+        //constructor minimal (default parameters pullup=true, inverted=false)
+        gpio_evaluatedSwitch( 
+                gpio_num_t gpio_num_declare
+                );
+
+        //constructor with optional parameters
+        gpio_evaluatedSwitch(
+                gpio_num_t gpio_num_declare,
+                bool pullup_declare,
+                bool inverted_declare=false
+                );
+
+        //constructor  with a function as source for input state instead of a gpio pin
+        gpio_evaluatedSwitch(bool (*getInputStatePtr_f)(void), bool inverted_f=false); 
+
+
+        //--- output ---         TODO make readonly? (e.g. public section: const int& x = m_x;)
+        bool state = false;
+        bool risingEdge = false;
+        bool fallingEdge = false;
+        uint32_t msPressed = 0;
+        uint32_t msReleased = 0;
+
+        //--- functions ---
+        void handle();  //Statemachine for debouncing and edge detection
+
+    private:
+        gpio_num_t gpio_num;
+        bool pullup;
+        bool inverted;
+        bool (*getInputStatePtr)(void); //pointer to function for getting current input state
+        inputSource_t inputSource = inputSource_t::GPIO;
+
+        enum class switchState {TRUE, FALSE, LOW, HIGH};
+        switchState p_state = switchState::FALSE;
+        bool inputState = false;
+        uint32_t timestampLow = 0;
+        uint32_t timestampHigh = 0;
+        void initGpio();
+
+};
+
+

components/max7219/max7219.c

@@ -236,7 +236,7 @@ esp_err_t max7219_draw_text_7seg(max7219_t *dev, uint8_t pos, const char *s)
 {
     CHECK_ARG(dev && s);
 
-    while (s && pos < dev->digits)
+    while (*s != '\0' && pos < dev->digits)
     {
         uint8_t c = get_char(dev, *s);
         if (*(s + 1) == '.')

docs/vfd/currently-used_T13-750W-12-h.txt

@@ -0,0 +1,2 @@
+currently the vfd 'T13-750W-12-h' is actually used. 
+Included documentation about T13-400W here too, modbus specification might be the same.

main/CMakeLists.txt

@@ -1,2 +1,20 @@
-idf_component_register(SRCS "main.c"
-                    INCLUDE_DIRS ".")
+idf_component_register(
+    SRCS 
+        "main.cpp"
+        "global.cpp"
+        "control.cpp"
+        "buzzer.cpp"
+        "vfd.cpp"
+        "display.cpp"
+        "cutter.cpp"
+        "switchesAnalog.cpp"
+		"stepper.cpp"
+        "guide-stepper.cpp"
+        "encoder.cpp"
+        "shutdown.cpp"
+    INCLUDE_DIRS 
+        "."
+    )
+
+# colored build output (errors, warnings...)
+idf_build_set_property(COMPILE_OPTIONS "-fdiagnostics-color=always" APPEND)

main/buzzer.cpp

@@ -0,0 +1,98 @@
+#include "buzzer.hpp"
+#include "config.h"
+
+static const char *TAG_BUZZER = "buzzer";
+
+//============================
+//========== init ============
+//============================
+//define gpio pin as output, initialize queue
+void buzzer_t::init(){
+    //define buzzer pin as output
+    gpio_pad_select_gpio(gpio_pin);
+    gpio_set_direction(gpio_pin, GPIO_MODE_OUTPUT);
+    //create queue
+    beepQueue = xQueueCreate( 20, sizeof( struct beepEntry ) );
+}
+
+
+//=============================
+//======== constructor ========
+//=============================
+//copy provided config parameters to private variables, run init function
+buzzer_t::buzzer_t(gpio_num_t gpio_pin_f, uint16_t msGap_f){
+    ESP_LOGI(TAG_BUZZER, "Initializing buzzer");
+    //copy configuration parameters to variables
+    gpio_pin = gpio_pin_f;
+    msGap = msGap_f;
+    //run init function to initialize gpio and queue
+    init();
+};
+
+
+//============================
+//=========== beep ===========
+//============================
+//function to add a beep command to the queue
+void buzzer_t::beep(uint8_t count, uint16_t msOn, uint16_t msOff, bool noGap){
+    //create entry struct with provided data
+    struct beepEntry entryInsert = {
+        count = count,
+        msOn = msOn,
+        msOff = msOff,
+        noGap = noGap
+    };
+
+    // Send a pointer to a struct AMessage object.  Don't block if the
+    // queue is already full.
+    //struct beepEntry *entryInsertPointer;
+    //entryInsertPointer = &entryInsertData;
+    ESP_LOGW(TAG_BUZZER, "Inserted object to queue - count=%d, msOn=%d, msOff=%d", entryInsert.count, entryInsert.msOn, entryInsert.msOff);
+    //xQueueGenericSend( beepQueue, ( void * ) &entryInsertPointer, ( TickType_t ) 0, queueSEND_TO_BACK );
+     xQueueSend( beepQueue, ( void * )&entryInsert, ( TickType_t ) 0 );
+}
+
+
+//==============================
+//======== processQueue ========
+//==============================
+void buzzer_t::processQueue(){
+    //struct for receiving incomming events
+    struct beepEntry entryRead = { };
+
+    //loop forever
+    while(1){
+        ESP_LOGD(TAG_BUZZER, "processQueue: waiting for beep command");
+
+        //if queue is ready
+        if( beepQueue != 0 )
+        {
+            // wait for a queue entry to be available indefinetely if INCLUDE_vTaskSuspend is enabled in the FreeRTOS config
+            // otherwise waits for at least 7 weeks
+            if( xQueueReceive( beepQueue, &entryRead, portMAX_DELAY ) )
+            {
+                ESP_LOGW(TAG_BUZZER, "Read entry from queue: count=%d, msOn=%d, msOff=%d", entryRead.count, entryRead.msOn, entryRead.msOff);
+
+                //beep requested count with requested delays
+                for (int i = entryRead.count; i--;){
+                    //turn on
+                    ESP_LOGD(TAG_BUZZER, "turning buzzer on");
+                    gpio_set_level(gpio_pin, 1);                
+                    vTaskDelay(entryRead.msOn / portTICK_PERIOD_MS);
+                    //turn off
+                    ESP_LOGD(TAG_BUZZER, "turning buzzer off");
+                    gpio_set_level(gpio_pin, 0);                
+                    vTaskDelay(entryRead.msOff / portTICK_PERIOD_MS);
+                }
+                if( entryRead.noGap == false ){
+                    //wait for minimum gap between beep events
+                    vTaskDelay(msGap / portTICK_PERIOD_MS);
+                }
+            }
+        }else{ //wait for queue to become available
+            vTaskDelay(50 / portTICK_PERIOD_MS);
+        }
+    }
+}
+
+

main/buzzer.hpp

@@ -0,0 +1,57 @@
+#pragma once
+
+#include <stdio.h>
+
+extern "C"
+{
+#include "freertos/FreeRTOS.h"
+#include "freertos/task.h"
+#include "driver/gpio.h"
+#include "esp_log.h"
+}
+
+#include "freertos/queue.h"
+
+
+
+//===================================
+//========= buzzer_t class ==========
+//===================================
+//class which blinks a gpio pin for the provided count and durations.
+//- 'processQueue' has to be run in a separate task
+//- uses a queue to queue up multiple beep commands
+class buzzer_t {
+    public:
+        //--- constructor ---
+        buzzer_t(gpio_num_t gpio_pin_f, uint16_t msGap_f = 200);
+
+        //--- functions ---
+        void processQueue(); //has to be run once in a separate task, waits for and processes queued events
+        void beep(uint8_t count, uint16_t msOn, uint16_t msOff, bool noGap = false);
+        //void clear(); (TODO - not implemented yet)
+        //void createTask(); (TODO - not implemented yet)
+
+        //--- variables ---
+        uint16_t msGap; //gap between beep entries (when multiple queued)
+        
+    private:
+        //--- functions ---
+        void init();
+
+        //--- variables ---
+        gpio_num_t gpio_pin;
+
+        struct beepEntry {
+            uint8_t count;
+            uint16_t msOn;
+            uint16_t msOff;
+            bool noGap;
+        };
+
+        //queue for queueing up multiple events while one is still processing
+        QueueHandle_t beepQueue = NULL;
+
+};
+
+
+

main/config.h

@@ -0,0 +1,151 @@
+#pragma once
+
+#include "esp_idf_version.h"
+
+//note: global variables and objects were moved to global.hpp
+
+//===================================
+//===== define output gpio pins =====
+//===================================
+//4x stepper mosfet outputs for VFD
+#define GPIO_VFD_FWD GPIO_NUM_4     //ST4
+#define GPIO_VFD_REV GPIO_NUM_5     //mos2
+#define GPIO_VFD_D0 GPIO_NUM_2      //ST2
+#define GPIO_VFD_D1 GPIO_NUM_15     //ST1
+//#define GPIO_VFD_D2 GPIO_NUM_15     //ST1 (D2 only used with 7.5kw vfd)
+
+#define GPIO_MOS1 GPIO_NUM_18       //mos1 (free) 2022.02.28: pin used for stepper
+#define GPIO_LAMP GPIO_NUM_0        //mos2 (5) 2022.02.28: lamp disabled, pin used for stepper
+#define GPIO_RELAY GPIO_NUM_13
+#define GPIO_BUZZER GPIO_NUM_12
+
+
+//==================================
+//==== define analog input pins ====
+//==================================
+#define GPIO_POTI GPIO_NUM_36
+#define ADC_CHANNEL_POTI ADC1_CHANNEL_0
+#define GPIO_4SW_TO_ANALOG GPIO_NUM_39
+#define ADC_CHANNEL_4SW_TO_ANALOG ADC1_CHANNEL_3 //gpio 39
+
+#define ADC_CHANNEL ADC_CHANNEL_0
+//#define ADC_LOW_VOLTAGE_THRESHOLD 1000 //adc value where shut down is detected (store certain values before power loss)
+#define GPIO_PIN GPIO_NUM_2
+
+#define ADC_CHANNEL_SUPPLY_VOLTAGE ADC1_CHANNEL_7//gpio35 onboard supply voltage
+//ADC1_CHANNEL_0 gpio36
+//ADC1_CHANNEL_6 gpio_34
+//ADC1_CHANNEL_3 gpio_39
+
+
+//=====================================
+//==== assign switches to objects =====
+//=====================================
+//see config.cpp for available evaluated switch objects
+#define SW_START sw_gpio_26
+#define SW_RESET sw_gpio_25
+#define SW_CUTTER_POS sw_gpio_14
+#define SW_SET     sw_gpio_analog_0
+#define SW_PRESET1 sw_gpio_analog_1
+#define SW_PRESET2 sw_gpio_analog_2
+#define SW_PRESET3 sw_gpio_analog_3
+#define SW_CUT sw_gpio_33
+#define SW_AUTO_CUT sw_gpio_32
+//#define ? sw_gpio_34
+//note: actual objects are created in global.cpp
+
+
+
+
+//=============================
+//======= configuration =======
+//=============================
+//--------------------------
+//----- display config -----
+//--------------------------
+#if ESP_IDF_VERSION < ESP_IDF_VERSION_VAL(4, 0, 0)
+#define HOST    HSPI_HOST
+#else
+#define HOST    SPI2_HOST
+#endif
+#define DISPLAY_PIN_NUM_MOSI GPIO_NUM_23
+#define DISPLAY_PIN_NUM_CLK GPIO_NUM_22
+#define DISPLAY_PIN_NUM_CS GPIO_NUM_27
+#define DISPLAY_DELAY 2000
+#define DISPLAY_BRIGHTNESS 8
+
+//--------------------------
+//----- encoder config -----
+//--------------------------
+#define ROT_ENC_A_GPIO GPIO_NUM_19
+#define ROT_ENC_B_GPIO GPIO_NUM_21
+#define ENABLE_HALF_STEPS false  // Set to true to enable tracking of rotary encoder at half step resolution
+#define FLIP_DIRECTION    false  // Set to true to reverse the clockwise/counterclockwise sense
+
+
+
+//--------------------------
+//----- stepper config -----
+//--------------------------
+//enable stepper test mode (dont start control and encoder task)
+//#define STEPPER_TEST
+//pins
+#define STEPPER_STEP_PIN		GPIO_NUM_18    //mos1
+#define STEPPER_DIR_PIN			GPIO_NUM_16     //ST3
+//driver settings
+#define STEPPER_STEPS_PER_MM	(200/2)	//steps/mm (steps-per-rot / spindle-slope)
+#define STEPPER_SPEED_DEFAULT	25		//mm/s
+#define STEPPER_SPEED_MIN		4		//mm/s  - speed threshold at which stepper immediately starts/stops
+#define STEPPER_ACCEL_INC		3		//steps/s increment per cycle 
+#define STEPPER_DECEL_INC		7		//steps/s decrement per cycle
+//options affecting movement are currently defined in guide-stepper.cpp
+
+
+//---------------------------
+//------- cable guide -------
+//---------------------------
+// default axis coordinates the guide changes direction (winding width)
+#define GUIDE_MIN_MM 0  // TODO add feature so guide stays at zero for some steps (negative MIN_MM?), currently seems appropriate for even winding
+#define GUIDE_MAX_MM 90 // 95 still to long at max pos - actual reel is 110, but currently guide turned out to stay at max position for too long, due to cable running diagonal from guide to reel
+
+// tolerance added to last stored position at previous shutdown.
+// When calibrating at startup the stepper moves for that sum to get track of zero position (ensure crashes into hardware limit for at least some time)
+#define AUTO_HOME_TRAVEL_ADD_TO_LAST_POS_MM 20
+#define MAX_TOTAL_AXIS_TRAVEL_MM 103 // max possible travel distance, needed as fallback for auto-home
+#define LAYER_THICKNESS_MM 5         // height of one cable layer on reel -> increase in radius every layer
+#define D_CABLE 6                    // determines winds per layer / guide speed
+#define D_REEL 160                   // start diameter of empty reel
+
+// max winding width that can be set using potentiometer (SET+PRESET1 buttons)
+#define MAX_SELECTABLE_WINDING_WIDTH_MM 100;
+// max target length that can be selected using potentiometer (SET button)
+#define MAX_SELECTABLE_LENGTH_POTI_MM 100000
+
+// calculate new winding width each time target length changes, according to custom thresholds defined in guide-stepper.cpp
+// if not defined, winding width is always GUIDE_MAX_MM even for short lengths
+#define DYNAMIC_WINDING_WIDTH_ENABLED
+
+
+//--------------------------
+//------ calibration -------
+//--------------------------
+//enable mode  encoder test for calibration (determine ENCODER_STEPS_PER_METER)
+//if defined, displays always show length and steps instead of the normal messages
+//#define ENCODER_TEST
+//TODO: add way to calibrate without flashing -> enter calibration mode with certain button sequence, enter steps-per-meter with poti, store in nvs
+
+//steps per meter
+//this value is determined experimentally while ENCODER_TEST is enabled
+//#define ENCODER_STEPS_PER_METER 2127 //until 2024.03.13 roll-v3-gummi-86.6mm - d=89.8mm
+#define ENCODER_STEPS_PER_METER 2118 //2024.03.13 roll-v3-gummi measured 86.5mm
+
+//millimeters added to target length
+//to ensure that length does not fall short when spool slightly rotates back after stop
+#define TARGET_LENGTH_OFFSET 0
+
+//millimeters lengthNow can be below lengthTarget to still stay in target_reached state
+#define TARGET_REACHED_TOLERANCE 5
+
+
+
+

main/control.cpp

@@ -0,0 +1,589 @@
+extern "C"
+{
+#include <stdio.h>
+#include <freertos/FreeRTOS.h>
+#include <freertos/task.h>
+#include <esp_idf_version.h>
+#include "freertos/queue.h"
+#include "esp_system.h"
+#include "esp_log.h"
+#include "driver/adc.h"
+
+#include "max7219.h"
+
+}
+#include <cmath>
+#include "config.h"
+#include "gpio_evaluateSwitch.hpp"
+#include "gpio_adc.hpp"
+#include "buzzer.hpp"
+#include "vfd.hpp"
+#include "display.hpp"
+#include "cutter.hpp"
+#include "encoder.hpp"
+#include "guide-stepper.hpp"
+#include "global.hpp"
+#include "control.hpp"
+
+
+//-----------------------------------------
+//--------------- variables ---------------
+//-----------------------------------------
+static const char *TAG = "control"; //tag for logging
+
+//control
+const char* systemStateStr[7] = {"COUNTING", "WINDING_START", "WINDING", "TARGET_REACHED", "AUTO_CUT_WAITING", "CUTTING", "MANUAL"};
+systemState_t controlState = systemState_t::COUNTING;
+static uint32_t timestamp_lastStateChange = 0;
+
+//display
+static char buf_disp1[10];// 8 digits + decimal point + \0
+static char buf_disp2[10];// 8 digits + decimal point + \0
+static char buf_tmp[15];
+
+//track length
+static int lengthNow = 0; //length measured in mm
+static int lengthTarget = 5000; //default target length in mm
+static int lengthRemaining = 0; //(target - now) length needed for reaching the target
+static int potiRead = 0; //voltage read from adc
+static uint32_t timestamp_motorStarted = 0; //timestamp winding started
+                                     
+//automatic cut
+static int cut_msRemaining = 0;
+static uint32_t timestamp_cut_lastBeep = 0;
+static uint32_t autoCut_delayMs = 2500; //TODO add this to config
+static bool autoCutEnabled = false; //store state of toggle switch (no hotswitch)
+
+//user interface
+static uint32_t timestamp_lastWidthSelect = 0;
+//ignore new set events for that time after last value set using poti
+#define DEAD_TIME_POTI_SET_VALUE 1000
+
+
+//-----------------------------------------
+//--------------- functions ---------------
+//-----------------------------------------
+
+//========================
+//===== change State =====
+//========================
+//function for changing the controlState with log output
+void changeState (systemState_t stateNew) {
+    //only proceed when state actually changed
+    if (controlState == stateNew) {
+        return; //already at target state -> nothing to do
+    }
+    //log change
+    ESP_LOGW(TAG, "changed state from %s to %s", systemStateStr[(int)controlState], systemStateStr[(int)stateNew]);
+    //change state
+    controlState = stateNew;
+    //update timestamp
+    timestamp_lastStateChange = esp_log_timestamp();
+}
+
+
+
+//=================================
+//===== handle Stop Condition =====
+//=================================
+//function that checks whether start button is released or target is reached 
+//and takes according action if so (used in multiple states)
+//returns true when stop condition was met, false when no action required
+bool handleStopCondition(handledDisplay * displayTop, handledDisplay * displayBot){
+    //--- stop conditions ---
+    //stop conditions that are checked in any mode
+    //target reached -> reached state, stop motor, display message
+    if (lengthRemaining <= 0 ) {
+        changeState(systemState_t::TARGET_REACHED);
+        vfd_setState(false);
+        displayTop->blink(1, 0, 1000, "  S0LL  ");
+        displayBot->blink(1, 0, 1000, "ERREICHT");
+        buzzer.beep(2, 100, 100);
+        return true;
+    }
+    //start button released -> idle state, stop motor, display message
+    else if (SW_START.state == false) {
+        changeState(systemState_t::COUNTING);
+        vfd_setState(false);
+        displayTop->blink(2, 900, 1000, "- STOP -");
+        displayBot->blink(2, 900, 1000, " TASTER ");
+        buzzer.beep(3, 200, 100);
+        return true;
+    } else {
+        return false;
+    }
+}
+
+
+
+//===================================
+//===== set dynamic speed level =====
+//===================================
+//function that sets the vfd speed level dynamically depending on the remaining distance
+//closer to target -> slower
+void setDynSpeedLvl(uint8_t lvlMax = 3){
+    uint8_t lvl;
+    //define speed level according to difference
+    if (lengthRemaining < 40) {
+        lvl = 0;
+    } else if (lengthRemaining < 300) {
+        lvl = 1;
+    } else if (lengthRemaining < 700) {
+        lvl = 2;
+    } else { //more than last step remaining
+        lvl = 3;
+    }
+    //limit to max lvl
+    if (lvl > lvlMax) {
+        lvl = lvlMax;
+    }
+    //update vfd speed level
+    vfd_setSpeedLevel(lvl);
+}
+
+
+
+           
+//========================
+//===== control task =====
+//========================
+//task that controls the entire machine
+void task_control(void *pvParameter)
+{
+    //-- initialize display --
+    max7219_t two7SegDisplays = display_init();
+    //create two separate custom handled display instances
+    handledDisplay displayTop(two7SegDisplays, 0);
+    handledDisplay displayBot(two7SegDisplays, 8);
+
+    //-- display welcome msg --
+    //display welcome message on two 7 segment displays
+    //currently show name and date and scrolling 'hello'
+    display_ShowWelcomeMsg(two7SegDisplays);
+
+    //-- set initial winding width for default length --
+    guide_setWindingWidth(guide_targetLength2WindingWidth(lengthTarget));
+
+    // ##############################
+    // ######## control loop ########
+    // ##############################
+    // repeatedly handle the machine
+    while(1){
+        vTaskDelay(10 / portTICK_PERIOD_MS);
+
+
+        //------ handle switches ------
+        //run handle functions for all switches used here
+        SW_START.handle();
+        SW_RESET.handle();
+        SW_SET.handle();
+        SW_PRESET1.handle();
+        SW_PRESET2.handle();
+        SW_PRESET3.handle();
+        SW_CUT.handle();
+        SW_AUTO_CUT.handle();
+
+
+        //------ handle cutter ------
+        //TODO: separate task for cutter?
+        cutter_handle();
+
+
+        //------ rotary encoder ------
+        //get current length since last reset
+        lengthNow = encoder_getLenMm();
+
+        
+        //--------- buttons ---------
+        //#### RESET switch ####
+        if (SW_RESET.risingEdge) {
+            //dont reset when press used for stopping pending auto-cut
+            if (controlState != systemState_t::AUTO_CUT_WAITING) {
+                guide_moveToZero(); //move axis guiding the cable to start position
+                encoder_reset(); //reset length measurement
+                lengthNow = 0;
+                buzzer.beep(1, 700, 100);
+                displayTop.blink(2, 100, 100, "1ST     ");
+                //TODO: stop cutter with reset switch?
+                //cutter_stop();
+            }
+        }
+
+        //### CUT switch ####
+        //start cut cycle immediately
+        if (SW_CUT.risingEdge) {
+            //stop cutter if already running
+            if (cutter_isRunning()) {
+                cutter_stop();
+                buzzer.beep(1, 600, 0);
+            }
+            else if (controlState == systemState_t::AUTO_CUT_WAITING) {
+                //do nothing when press used for stopping pending auto-cut
+            }
+            //start cutter when motor not active
+            else if (controlState != systemState_t::WINDING_START //TODO use vfd state here?
+                    && controlState != systemState_t::WINDING) {
+                cutter_start();
+                buzzer.beep(1, 70, 50);
+            }
+            //error cant cut while motor is on
+            else {
+                buzzer.beep(6, 100, 50);
+            }
+        }
+       
+        //#### AUTO_CUT toggle sw ####
+        //beep at change
+        if (SW_AUTO_CUT.risingEdge) {
+            buzzer.beep(2, 100, 50);
+        } else if (SW_AUTO_CUT.fallingEdge) {
+            buzzer.beep(1, 400, 50);
+        }
+        //update enabled state
+        if (SW_AUTO_CUT.state) {
+            //enable autocut when not in target_reached state
+            //(prevent immediate/unexpected cut)
+            if (controlState != systemState_t::TARGET_REACHED) {
+                autoCutEnabled = true;
+            }
+        } else {
+            //disable anytime (also stops countdown to auto cut)
+            autoCutEnabled = false;
+        }
+
+        //#### manual mode ####
+        //switch to manual motor control (2 buttons + poti)
+        if ( SW_PRESET2.state && (SW_PRESET1.state || SW_PRESET3.state) && controlState != systemState_t::MANUAL ) {
+            //enable manual control
+            changeState(systemState_t::MANUAL);
+            buzzer.beep(3, 100, 60);
+        }
+
+        //##### SET switch + Potentiometer #####
+        //## set winding-width (SET+PRESET1+POTI) ##
+        // set winding width (axis travel) with poti position
+        // when SET and PRESET1 button are pressed
+        if (SW_SET.state == true && SW_PRESET1.state == true) {
+            timestamp_lastWidthSelect = esp_log_timestamp();
+            //read adc
+            potiRead = gpio_readAdc(ADC_CHANNEL_POTI); //0-4095
+            //scale to target length range
+            uint8_t windingWidthNew = (float)potiRead / 4095 * MAX_SELECTABLE_WINDING_WIDTH_MM;
+            //apply hysteresis and round to whole meters //TODO optimize this
+            if (windingWidthNew % 5 < 2) { //round down if remainder less than 2mm
+                ESP_LOGD(TAG, "Poti input = %d -> rounding down", windingWidthNew);
+                windingWidthNew = (windingWidthNew/5 ) * 5; //round down
+            } else if (windingWidthNew % 5 > 4 ) { //round up if remainder more than 4mm
+                ESP_LOGD(TAG, "Poti input = %d -> rounding up", windingWidthNew);
+                windingWidthNew = (windingWidthNew/5 + 1) * 5; //round up
+            } else {
+                ESP_LOGD(TAG, "Poti input = %d -> hysteresis", windingWidthNew);
+                windingWidthNew = guide_getWindingWidth();
+            }
+            //update target width and beep when effectively changed
+            if (windingWidthNew != guide_getWindingWidth()) {
+                //TODO update at button release only?
+                guide_setWindingWidth(windingWidthNew);
+                ESP_LOGW(TAG, "Changed winding width to %d mm", windingWidthNew);
+                buzzer.beep(1, 30, 10);
+            }
+        }
+
+        //## set target length (SET+POTI) ##
+        //set target length to poti position when only SET button is pressed and certain dead time passed after last setWindingWidth (SET and PRESET1 button) to prevent set target at release
+        // FIXME: when going to edit the winding width (SET+PRESET1) sometimes the target-length also updates when initially pressing SET -> update only at actual poti change (works sometimes)
+        else if (SW_SET.state == true && (esp_log_timestamp() - timestamp_lastWidthSelect > DEAD_TIME_POTI_SET_VALUE)) {
+            //read adc
+            potiRead = gpio_readAdc(ADC_CHANNEL_POTI); //0-4095
+            //scale to target length range
+            int lengthTargetNew = (float)potiRead / 4095 * MAX_SELECTABLE_LENGTH_POTI_MM;
+            //apply hysteresis and round to whole meters //TODO optimize this
+            if (lengthTargetNew % 1000 < 200) { //round down if less than .2 meter
+                ESP_LOGD(TAG, "Poti input = %d -> rounding down", lengthTargetNew);
+                lengthTargetNew = (lengthTargetNew/1000 ) * 1000; //round down
+            } else if (lengthTargetNew % 1000 > 800 ) { //round up if more than .8 meter
+                ESP_LOGD(TAG, "Poti input = %d -> rounding up", lengthTargetNew);
+                lengthTargetNew = (lengthTargetNew/1000 + 1) * 1000; //round up
+            } else {
+                ESP_LOGD(TAG, "Poti input = %d -> hysteresis", lengthTargetNew);
+                lengthTargetNew = lengthTarget;
+            }
+            //update target length and beep when effectively changed
+            if (lengthTargetNew != lengthTarget) {
+                //TODO update lengthTarget only at button release?
+                lengthTarget = lengthTargetNew;
+                guide_setWindingWidth(guide_targetLength2WindingWidth(lengthTarget));
+                ESP_LOGI(TAG, "Changed target length to %d mm", lengthTarget);
+                buzzer.beep(1, 25, 10);
+            }
+        }
+        //beep start and end of editing
+        if (SW_SET.risingEdge) {
+            buzzer.beep(1, 70, 50);
+        }
+        if (SW_SET.fallingEdge) {
+            buzzer.beep(2, 70, 50);
+            displayBot.blink(2, 100, 100, "S0LL    ");
+        }
+
+
+        //##### target length preset buttons #####
+        if (controlState != systemState_t::MANUAL && SW_SET.state == false) { //dont apply preset length while controlling motor with preset buttons
+            if (SW_PRESET1.risingEdge) {
+                lengthTarget = 5000;
+                guide_setWindingWidth(guide_targetLength2WindingWidth(lengthTarget));
+                buzzer.beep(lengthTarget/1000, 25, 30);
+                displayBot.blink(2, 100, 100, "S0LL    ");
+            }
+            else if (SW_PRESET2.risingEdge) {
+                lengthTarget = 10000;
+                guide_setWindingWidth(guide_targetLength2WindingWidth(lengthTarget));
+                buzzer.beep(lengthTarget/1000, 25, 30);
+                displayBot.blink(2, 100, 100, "S0LL    ");
+            }
+            else if (SW_PRESET3.risingEdge) {
+                lengthTarget = 15000;
+                guide_setWindingWidth(guide_targetLength2WindingWidth(lengthTarget));
+                buzzer.beep(lengthTarget/1000, 25, 30);
+                displayBot.blink(2, 100, 100, "S0LL    ");
+            }
+        }
+
+
+        //---------------------------
+        //--------- control ---------
+        //---------------------------
+        //statemachine handling the sequential winding process
+
+        //calculate current length difference
+        lengthRemaining = lengthTarget - lengthNow + TARGET_LENGTH_OFFSET;
+
+        //--- statemachine ---
+        switch (controlState) {
+            case systemState_t::COUNTING: //no motor action, just show current length on display
+                vfd_setState(false);
+                //TODO check stop condition before starting - prevents motor from starting 2 cycles when already at target
+                //--- start winding to length ---
+                if (SW_START.risingEdge) {
+                    changeState(systemState_t::WINDING_START);
+                    vfd_setSpeedLevel(1); //start at low speed 
+                    vfd_setState(true); //start motor
+                    timestamp_motorStarted = esp_log_timestamp(); //save time started
+                    buzzer.beep(1, 100, 0);
+                } 
+                break;
+
+            case systemState_t::WINDING_START: //wind slow for certain time
+                //set vfd speed depending on remaining distance 
+                setDynSpeedLvl(1); //limit to speed lvl 1 (force slow start)
+                //switch to WINDING state (full speed) when 3s have passed
+                if (esp_log_timestamp() - timestamp_motorStarted > 3000) {
+                    changeState(systemState_t::WINDING);
+                }
+                handleStopCondition(&displayTop, &displayBot); //stops if button released or target reached
+                //TODO: cancel when there was no cable movement during start time?
+                break;
+
+            case systemState_t::WINDING: //wind fast, slow down when close
+                //set vfd speed depending on remaining distance 
+                setDynSpeedLvl(); //set motor speed, slow down when close to target
+                handleStopCondition(&displayTop, &displayBot); //stops if button released or target reached
+                //TODO: cancel when there is no cable movement anymore e.g. empty / timeout?
+                break;
+
+            case systemState_t::TARGET_REACHED: //prevent further motor rotation and start auto-cut
+                vfd_setState(false);
+                //switch to counting state when no longer at or above target length
+                if ( lengthNow < lengthTarget - TARGET_REACHED_TOLERANCE ) {
+                    changeState(systemState_t::COUNTING);
+                }
+                //initiate countdown to auto-cut if enabled
+                else if ( (autoCutEnabled)
+                        && (esp_log_timestamp() - timestamp_lastStateChange > 300) ) { //wait for dislay msg "reached" to finish
+                    changeState(systemState_t::AUTO_CUT_WAITING);
+                }
+                //show msg when trying to start, but target is already reached (-> reset button has to be pressed)
+                if (SW_START.risingEdge) {
+                    buzzer.beep(2, 50, 30);
+                    displayTop.blink(2, 600, 500, "  S0LL  ");
+                    displayBot.blink(2, 600, 500, "ERREICHT");
+                }
+                break;
+
+            case systemState_t::AUTO_CUT_WAITING: //handle delayed start of cut
+                cut_msRemaining = autoCut_delayMs - (esp_log_timestamp() - timestamp_lastStateChange);
+                //- countdown stop conditions -
+                //stop with any button
+                if (!autoCutEnabled
+                        || SW_RESET.state || SW_CUT.state 
+                        || SW_SET.state || SW_PRESET1.state
+                        || SW_PRESET2.state || SW_PRESET3.state) {//TODO: also stop when target not reached anymore?
+                    changeState(systemState_t::COUNTING);
+                    buzzer.beep(5, 100, 50);
+                }
+                //- trigger cut if delay passed -
+                else if (cut_msRemaining <= 0) {
+                    cutter_start();
+                    changeState(systemState_t::CUTTING);
+                }
+                //- beep countdown -
+                //time passed since last beep  >  time remaining / 6
+                else if ( (esp_log_timestamp() - timestamp_cut_lastBeep)  > (cut_msRemaining / 6)
+                        && (esp_log_timestamp() - timestamp_cut_lastBeep) > 50 ) { //dont trigger beeps faster than beep time
+                    buzzer.beep(1, 50, 0);
+                    timestamp_cut_lastBeep = esp_log_timestamp();
+                }
+                break;
+
+            case systemState_t::CUTTING: //prevent any action while cutter is active
+                //exit when finished cutting
+                if (cutter_isRunning() == false) {
+                    //TODO stop if start buttons released?
+                    changeState(systemState_t::COUNTING);
+                    //TODO reset automatically or wait for manual reset?
+                    guide_moveToZero(); //move axis guiding the cable to start position
+                    encoder_reset(); //reset length measurement
+                    lengthNow = 0;
+                    buzzer.beep(1, 700, 100);
+                }
+                break;
+
+            case systemState_t::MANUAL: //manually control motor via preset buttons + poti
+                //read poti value
+                potiRead = gpio_readAdc(ADC_CHANNEL_POTI); //0-4095
+                //scale poti to speed levels 0-3
+                uint8_t level = round( (float)potiRead / 4095 * 3 );
+                //exit manual mode if preset2 released
+                if ( SW_PRESET2.state == false ) {
+                    changeState(systemState_t::COUNTING);
+                    buzzer.beep(1, 1000, 100);
+                }
+                //P2 + P1 -> turn left
+                else if ( SW_PRESET1.state && !SW_PRESET3.state ) {
+                    vfd_setSpeedLevel(level);
+                    vfd_setState(true, REV);
+                    sprintf(buf_disp2, "[--%02i   ", level);
+                    //                  123 45 678
+                }
+                //P2 + P3 -> turn right
+                else if ( SW_PRESET3.state && !SW_PRESET1.state ) {
+                    vfd_setSpeedLevel(level);
+                    vfd_setState(true, FWD);
+                    sprintf(buf_disp2, "   %02i--]", level);
+                }
+                //no valid switch combination -> turn off motor
+                else {
+                    vfd_setState(false);
+                    sprintf(buf_disp2, "   %02i   ", level);
+                }
+        }
+
+
+#ifdef ENCODER_TEST
+        //--------------------------
+        //------ encoder test ------
+        //--------------------------
+        //mode for calibrating the cable length measurement (determine ENCODER_STEPS_PER_METER in config.h)
+        //run display handle functions
+        displayTop.handle();
+        displayBot.handle();
+        //-- show encoder steps on display1 ---
+        sprintf(buf_disp1, "EN %05d", encoder_getSteps()); //count
+        displayTop.showString(buf_disp1);
+        //--- show converted distance on display2 ---
+        sprintf(buf_disp2, "Met %5.3f", (float)lengthNow/1000); //m
+        displayBot.showString(buf_disp2);
+        //--- beep every 0.5m ---
+        //note: only works precisely in forward/positive direction, in reverse it it beeps by tolerance too early
+        static int lengthBeeped = 0;
+        if (lengthNow % 500 < 50) { //with tolerance in case of missed exact value
+            if (fabs(lengthNow - lengthBeeped) >= 400) { //dont beep multiple times at same distance
+                //TODO: add case for reverse direction. currently beeps 50mm too early
+                if (lengthNow % 1000 < 50) // 1m beep
+                    buzzer.beep(1, 400, 100);
+                else // 0.5m beep
+                    buzzer.beep(1, 200, 100);
+                lengthBeeped = lengthNow;
+            }
+        }
+#else //not in encoder calibration mode
+
+        //--------------------------
+        //-------- display1 --------
+        //--------------------------
+        //run handle function
+        displayTop.handle();
+        //indicate upcoming cut when pending
+        if (controlState == systemState_t::AUTO_CUT_WAITING) {
+            displayTop.blinkStrings(" CUT 1N ", "        ", 70, 30);
+        }
+        //setting winding width: blink info message
+        else if (SW_SET.state && SW_PRESET1.state){
+            displayTop.blinkStrings("SET WIND", " WIDTH  ", 900, 900);
+        }
+        //otherwise show current position
+        else {
+            sprintf(buf_tmp, "1ST %5.4f", (float)lengthNow/1000);
+            //                123456789
+            //limit length to 8 digits + decimal point (drop decimal places when it does not fit)
+            sprintf(buf_disp1, "%.9s", buf_tmp);
+            displayTop.showString(buf_disp1);
+        }
+
+        //--------------------------
+        //-------- display2 --------
+        //--------------------------
+        //run handle function
+        displayBot.handle();
+        //notify that cutter is active
+        if (cutter_isRunning()) {
+            displayBot.blinkStrings("CUTTING]", "CUTTING[", 100, 100);
+        }
+        //show ms countdown to cut when pending
+        else if (controlState == systemState_t::AUTO_CUT_WAITING) {
+            sprintf(buf_disp2, "  %04d  ", cut_msRemaining);
+            //displayBot.showString(buf_disp2); //TODO:blink "erreicht" overrides this. for now using blink as workaround
+            displayBot.blinkStrings(buf_disp2, buf_disp2, 100, 100);
+        }
+        //manual state: blink "manual"
+        else if (controlState == systemState_t::MANUAL) {
+            displayBot.blinkStrings(" MANUAL ", buf_disp2, 400, 800);
+        }
+        //setting winding width: blink currently set windingWidth
+        else if (SW_SET.state && SW_PRESET1.state){
+            sprintf(buf_tmp, "  %03d mm", guide_getWindingWidth());
+            displayBot.blinkStrings(buf_tmp, "        ", 300, 100);
+        }
+        //setting target length: blink target length
+        else if (SW_SET.state == true) {
+            sprintf(buf_tmp, "S0LL%5.3f", (float)lengthTarget/1000);
+            displayBot.blinkStrings(buf_tmp, "S0LL    ", 300, 100);
+        }
+        //otherwise show target length
+        else {
+            //sprintf(buf_disp2, "%06.1f cm", (float)lengthTarget/10); //cm
+            sprintf(buf_tmp, "S0LL%5.3f", (float)lengthTarget/1000); //m
+            //                1234  5678
+            displayBot.showString(buf_tmp);
+        }
+
+#endif // end else ifdef ENCODER_TEST
+
+        //----------------------------
+        //------- control lamp -------
+        //----------------------------
+        //basic functionality of lamp:
+        //turn on when not idling
+        //TODO: add switch-case for different sates
+        //e.g. blink with different frequencies in different states
+        if (controlState != systemState_t::COUNTING
+                && controlState != systemState_t::TARGET_REACHED) {
+            gpio_set_level(GPIO_LAMP, 1);
+        }
+        else {
+            gpio_set_level(GPIO_LAMP, 0);
+        }
+
+    } //end while(1)
+
+} //end task_control

main/control.hpp

@@ -0,0 +1,12 @@
+#pragma once
+
+
+//enum describing the state of the system
+enum class systemState_t {COUNTING, WINDING_START, WINDING, TARGET_REACHED, AUTO_CUT_WAITING, CUTTING, MANUAL};
+
+//array with enum as strings for logging states
+extern const char* systemStateStr[7];
+
+
+//task that controls the entire machine (has to be created as task in main function)
+void task_control(void *pvParameter);

main/cutter.cpp

@@ -0,0 +1,168 @@
+#include "cutter.hpp"
+#include "config.h"
+#include "global.hpp"
+
+const char* cutter_stateStr[5] = {"IDLE", "START", "CUTTING", "CANCELED", "TIMEOUT"}; //define strings for logging the state
+                                                                          
+
+//---------------------------
+//----- local functions -----
+//---------------------------
+//declare local functions
+void setState(cutter_state_t stateNew);
+bool checkTimeout();
+
+
+
+//---------------------------
+//----- local variables -----
+//---------------------------
+static cutter_state_t cutter_state = cutter_state_t::IDLE;
+static uint32_t timestamp_turnedOn;
+static uint32_t msTimeout = 3000;
+static const char *TAG = "cutter"; //tag for logging
+
+
+
+//=========================
+//========= start =========
+//=========================
+void cutter_start(){
+    setState(cutter_state_t::START);
+    //starts motor on state change
+}
+
+
+
+//========================
+//========= stop =========
+//========================
+void cutter_stop(){
+    if(cutter_state != cutter_state_t::IDLE){
+        setState(cutter_state_t::CANCELED);
+    }
+}
+
+
+
+//===========================
+//===== cutter_getState =====
+//===========================
+cutter_state_t cutter_getState(){
+    return cutter_state;
+}
+
+
+
+//============================
+//===== cutter_isRunning =====
+//============================
+bool cutter_isRunning(){
+    if (cutter_state == cutter_state_t::START 
+            || cutter_state == cutter_state_t::CUTTING) {
+        return true;
+    } else {
+        return false;
+    }
+}
+
+
+
+//---------------------------
+//-------- setState ---------
+//---------------------------
+//local function for changing state, taking corresponding actions and sending log output
+void setState(cutter_state_t stateNew){
+    //only proceed and send log output when state or direction actually changed
+    if ( cutter_state == stateNew) {
+        //already at target state -> do nothing
+        return;
+    }
+
+    //log old and new state
+    ESP_LOGI(TAG, "CHANGING state from: %s",cutter_stateStr[(int)cutter_state]);
+    ESP_LOGI(TAG, "CHANGING state   to: %s",cutter_stateStr[(int)stateNew]);
+    //update stored state
+    cutter_state = stateNew;
+
+    switch(stateNew){
+        case cutter_state_t::IDLE:
+        case cutter_state_t::TIMEOUT:
+        case cutter_state_t::CANCELED:
+            //--- turn motor off ---
+            gpio_set_level(GPIO_RELAY, 0);
+            break;
+
+        case cutter_state_t::START:
+        case cutter_state_t::CUTTING:
+            //--- turn motor on ---
+            gpio_set_level(GPIO_RELAY, 1);
+            //update state, timestamp
+            timestamp_turnedOn = esp_log_timestamp();
+            break;
+    }
+}
+
+
+
+//--------------------------
+//------ checkTimeout ------
+//--------------------------
+//local function that checks for timeout
+bool checkTimeout(){
+    if (esp_log_timestamp() - timestamp_turnedOn > msTimeout){
+        setState(cutter_state_t::TIMEOUT);
+        return true;
+    } else {
+        return false;
+    }
+}
+
+
+
+
+//========================
+//======== handle ========
+//========================
+//function that handles the cutter logic -> has to be run repeatedly
+void cutter_handle(){
+    //handle evaluated switch (position switch)
+    SW_CUTTER_POS.handle();
+    //TODO add custom thresholds once at initialization?
+    //SW_CUTTER_POS.minOnMs = 10;
+    //SW_CUTTER_POS.minOffMs = 10;
+
+    switch(cutter_state){
+        case cutter_state_t::IDLE:
+        case cutter_state_t::TIMEOUT:
+        case cutter_state_t::CANCELED:
+            //wait for state change via cutter_start();
+            break;
+
+        case cutter_state_t::START:
+            //--- moved away from idle position ---
+            //if (gpio_get_level(GPIO_CUTTER_POS_SW) == 0){ //contact closed
+            if (SW_CUTTER_POS.state == true) { //contact closed -> not at idle pos anymore
+                setState(cutter_state_t::CUTTING);
+            }
+            //--- timeout ---
+            else {
+                checkTimeout();
+            }
+            break;
+
+        case cutter_state_t::CUTTING:
+            //--- idle position reached ---
+            //if (gpio_get_level(GPIO_CUTTER_POS_SW) == 1){ //contact not closed
+            //TODO: add min on duration
+            if (SW_CUTTER_POS.state == false) { //contact open -> at idle pos
+                setState(cutter_state_t::IDLE);
+            }
+            //--- timeout ---
+            else {
+                checkTimeout();
+            }
+            break;
+    }
+}
+

main/cutter.hpp

@@ -0,0 +1,37 @@
+#pragma once
+
+extern "C"
+{
+#include <stdio.h>
+#include "esp_log.h"
+}
+
+#include "buzzer.hpp"
+#include "display.hpp"
+#include "gpio_evaluateSwitch.hpp"
+
+
+//--- variables ---
+//enum for state of cutter
+enum class cutter_state_t {IDLE, START, CUTTING, CANCELED, TIMEOUT};
+//string for logging the state name
+extern const char* cutter_stateStr[5];
+
+
+
+//--- functions ---
+//trigger cut cycle (no effect if already running)
+void cutter_start();
+
+//cancel cutting action
+void cutter_stop();
+
+//return current state
+cutter_state_t cutter_getState();
+//TODO: bool cutter_isOn() (simply return boolean instead of enum)
+
+//check if cutter is currently operating
+bool cutter_isRunning();
+
+//handle function - has to be run repeatedly
+void cutter_handle();

main/display.cpp

@@ -0,0 +1,204 @@
+#include "display.hpp"
+
+#include "config.h"
+
+//=== variables ===
+static const char *TAG = "display"; //tag for logging
+
+
+
+//==============================
+//======== init display ========
+//==============================
+//initialize display with parameters defined in config.hpp
+//TODO: dont use global variables/macros here
+max7219_t display_init(){
+    
+    ESP_LOGI(TAG, "initializing display...");
+    // Configure SPI bus
+    spi_bus_config_t cfg;
+    memset(&cfg, 0, sizeof(spi_bus_config_t)); //init bus config with 0 to prevent bugs with random flags
+    cfg.mosi_io_num = DISPLAY_PIN_NUM_MOSI;
+    cfg.miso_io_num = -1;
+    cfg.sclk_io_num = DISPLAY_PIN_NUM_CLK;
+    cfg.quadwp_io_num = -1;
+    cfg.quadhd_io_num = -1;
+    cfg.max_transfer_sz = 0;
+    cfg.flags = 0;
+    ESP_ERROR_CHECK(spi_bus_initialize(HOST, &cfg, 1));
+
+    // Configure device
+    max7219_t dev;
+    dev.cascade_size = 2;
+    dev.digits = 0;
+    dev.mirrored = true;
+    ESP_ERROR_CHECK(max7219_init_desc(&dev, HOST, MAX7219_MAX_CLOCK_SPEED_HZ, DISPLAY_PIN_NUM_CS));
+    ESP_ERROR_CHECK(max7219_init(&dev));
+    //0...15
+    ESP_ERROR_CHECK(max7219_set_brightness(&dev, DISPLAY_BRIGHTNESS));
+    return dev;
+    //display = dev;
+    ESP_LOGI(TAG, "initializing display - done");
+}
+
+
+
+//===================================
+//======= display welcome msg =======
+//===================================
+void display_ShowWelcomeMsg(max7219_t dev){
+    //display welcome message on two 7 segment displays
+    //show name and date
+    ESP_LOGI(TAG, "showing startup message...");
+    max7219_clear(&dev);
+    max7219_draw_text_7seg(&dev, 0, "CUTTER  15.03.2024");
+    //                                   1234567812 34 5678
+    vTaskDelay(pdMS_TO_TICKS(700));
+    //scroll "hello" over 2 displays
+    for (int offset = 0; offset < 23; offset++) {
+        max7219_clear(&dev);
+        char hello[40] = "                HELL0                 ";
+        max7219_draw_text_7seg(&dev, 0, hello + (22 - offset) );
+        vTaskDelay(pdMS_TO_TICKS(50));
+    }
+
+    //noticed rare bug that one display does not initialize / is not configured correctly after start
+    //initialize display again after the welcome message in case it did not work the first time
+    ESP_ERROR_CHECK(max7219_init(&dev));
+    ESP_ERROR_CHECK(max7219_set_brightness(&dev, DISPLAY_BRIGHTNESS));
+}
+
+
+
+
+
+//---------------------------------
+//---------- constructor ----------
+//---------------------------------
+handledDisplay::handledDisplay(max7219_t displayDevice, uint8_t posStart_f) {
+    ESP_LOGI(TAG, "Creating handledDisplay instance with startPos at %i", posStart);
+    //copy variables
+    dev = displayDevice;
+    posStart = posStart_f;
+}
+
+
+
+//================================
+//========== showString ==========
+//================================
+//function that displays a given string on the display
+void handledDisplay::showString(const char * buf, uint8_t pos_f){
+    //calculate actual absolute position
+    posCurrent = posStart + pos_f;
+    //copy the desired string
+    strcpy(strOn, buf);
+    //exit blinking mode
+    if (mode == displayMode::BLINK_STRINGS){
+        mode = displayMode::NORMAL;
+        ESP_LOGI(TAG, "pos:%i - disable blink strings mode -> normal mode str='%s'", posStart, strOn);
+    }
+    handle(); //draws the text depending on mode
+}
+
+
+
+//TODO: blinkStrings() and blink() are very similar - can be optimized?
+//only difficulty is the reset behaivor of blinkStrings through showString (blink does not reset)
+
+//==================================
+//========== blinkStrings ==========
+//==================================
+//function switches between two strings in a given interval
+void handledDisplay::blinkStrings(const char * strOn_f, const char * strOff_f, uint32_t msOn_f, uint32_t msOff_f){
+    //copy/update variables
+    strcpy(strOn, strOn_f);
+    strcpy(strOff, strOff_f);
+    msOn = msOn_f;
+    msOff = msOff_f;
+    //if changed to blink mode just now:
+    if (mode != displayMode::BLINK_STRINGS) {
+        //switch mode
+        ESP_LOGI(TAG, "pos:%i - toggle blink strings mode on/off=%d/%d stings='%s'/'%s'", posStart, msOn, msOff, strOn, strOff);
+        mode = displayMode::BLINK_STRINGS;
+        //start with on state
+        state = true;
+        timestampOn = esp_log_timestamp();
+    }
+    //run handle function for display update
+    handle();
+}
+
+
+
+//===============================
+//============ blink ============
+//===============================
+//function triggers certain count and interval of off durations
+void handledDisplay::blink(uint8_t count_f, uint32_t msOn_f, uint32_t msOff_f, const char * strOff_f) {
+    //copy/update parameters
+    count = count_f;
+    msOn = msOn_f;
+    msOff = msOff_f;
+    strcpy(strOff, strOff_f);
+    //FIXME this strings length must be dynamic depending on display size (posEnd - posStart) -> otherwise overwrites next segments if other display size or start pos
+    //if changed to blink mode just now:
+    if (mode != displayMode::BLINK) {
+        //set to blink mode
+        mode = displayMode::BLINK;
+        ESP_LOGI(TAG, "pos:%i - start blinking: count=%i  on/off=%d/%d sting='%s'",posStart, count, msOn, msOff, strOff);
+        //start with off state
+        state = false;
+        timestampOff = esp_log_timestamp();
+    }
+    //run handle function for display update
+    handle();
+}
+
+
+
+//================================
+//============ handle ============
+//================================
+//function that handles time based modes
+//writes text to the 7 segment display depending on the current mode
+void handledDisplay::handle() {
+    switch (mode){
+        case displayMode::NORMAL:
+            //daw given string
+            max7219_draw_text_7seg(&dev, posCurrent, strOn);
+            break;
+
+        case displayMode::BLINK:
+        case displayMode::BLINK_STRINGS:
+            //--- define state on/off ---
+            if (state == true){ //display in ON state
+                if (esp_log_timestamp() - timestampOn > msOn){
+                    state = false;
+                    timestampOff = esp_log_timestamp();
+                    //decrement remaining counts in BLINK mode each cycle
+                    if (mode == displayMode::BLINK) count--;
+                }
+            } else { //display in OFF state
+                if (esp_log_timestamp() - timestampOff > msOff) {
+                    state = true;
+                    timestampOn = esp_log_timestamp();
+                }
+            }
+            //--- draw text of current state ---
+            if (state) {
+                max7219_draw_text_7seg(&dev, posStart, strOn);
+            } else {
+                max7219_draw_text_7seg(&dev, posStart, strOff);
+            }
+
+            //--- check finished condition in BLINK mode ---
+            if (mode == displayMode::BLINK){
+                if (count == 0) {
+                    mode = displayMode::NORMAL;
+                    ESP_LOGI(TAG, "pos:%i - finished blinking -> normal mode", posStart);
+                }
+            }
+            break;
+    }
+}

main/display.hpp

@@ -0,0 +1,64 @@
+#pragma once
+extern "C"
+{
+#include <stdio.h>
+#include <freertos/FreeRTOS.h>
+#include <freertos/task.h>
+#include <esp_idf_version.h>
+#include "freertos/queue.h"
+#include "esp_system.h"
+#include "esp_log.h"
+#include "driver/adc.h"
+
+#include <max7219.h>
+#include "rotary_encoder.h"
+}
+#include <cstring>
+
+
+
+//function for initializing the display using configuration from macros in config.h
+max7219_t display_init();
+
+//show welcome message on the entire display
+void display_ShowWelcomeMsg(max7219_t displayDevice);
+
+enum class displayMode {NORMAL, BLINK_STRINGS, BLINK};
+
+class handledDisplay {
+    public:
+        //--- constructor ---
+        //TODO add posMax to prevent writing in segments of other instance
+        handledDisplay(max7219_t displayDevice, uint8_t posStart);
+
+        //--- methods ---
+        void showString(const char * buf, uint8_t pos = 0);
+        //function switches between two strings in a given interval
+        void blinkStrings(const char * strOn, const char * strOff, uint32_t msOn, uint32_t msOff);
+        //triggers certain count of blinking between currently shown string and off or optional certain string
+        void blink(uint8_t count, uint32_t msOn, uint32_t msOff, const char * strOff = "        ");
+        //function that handles time based modes and writes text to display
+        void handle(); //has to be run regularly when blink method is used
+
+        //TODO: blinkStrings and blink are very similar - optimize?
+        //TODO: add 'scroll string' method
+
+
+    private:
+        //--- variables ---
+        //config
+        max7219_t dev;
+        uint8_t posStart; //absolute position this display instance starts (e.g. multiple or very long 7 segment display)
+        uint8_t posCurrent;
+
+        displayMode mode = displayMode::NORMAL;
+        //blink modes
+        uint8_t count = 0;
+        char strOn[20];
+        char strOff[20];
+        bool state = false;
+        uint32_t msOn;
+        uint32_t msOff;
+        uint32_t timestampOn;
+        uint32_t timestampOff;
+};

main/encoder.cpp

@@ -0,0 +1,79 @@
+extern "C" {
+#include <freertos/FreeRTOS.h>
+#include <freertos/task.h>
+#include "esp_system.h"
+#include "esp_log.h"
+
+#include "rotary_encoder.h"
+}
+
+#include "encoder.hpp"
+#include "config.h"
+#include "global.hpp"
+
+
+//----------------------------
+//----- global variables -----
+//----------------------------
+static rotary_encoder_info_t encoder; //encoder device/info
+QueueHandle_t encoder_queue = NULL; //encoder event queue
+
+
+
+//-------------------------
+//------- functions -------
+//-------------------------
+
+//======================
+//==== encoder_init ====
+//======================
+//initialize encoder and return event queue
+QueueHandle_t encoder_init(){
+    // esp32-rotary-encoder requires that the GPIO ISR service is installed before calling rotary_encoder_register()
+    ESP_ERROR_CHECK(gpio_install_isr_service(0));
+
+    // Initialise the rotary encoder device with the GPIOs for A and B signals
+    ESP_ERROR_CHECK(rotary_encoder_init(&encoder, ROT_ENC_A_GPIO, ROT_ENC_B_GPIO));
+    ESP_ERROR_CHECK(rotary_encoder_enable_half_steps(&encoder, ENABLE_HALF_STEPS));
+#ifdef FLIP_DIRECTION
+    ESP_ERROR_CHECK(rotary_encoder_flip_direction(&encoder));
+#endif
+
+    // Create a queue for events from the rotary encoder driver.
+    // Tasks can read from this queue to receive up to date position information.
+    QueueHandle_t event_queue = rotary_encoder_create_queue();
+    ESP_ERROR_CHECK(rotary_encoder_set_queue(&encoder, event_queue));
+    return event_queue;
+}
+
+
+//========================
+//=== encoder_getSteps ===
+//========================
+//get steps counted since last reset
+int encoder_getSteps(){
+    // Poll current position and direction
+    rotary_encoder_state_t encoderState;
+    rotary_encoder_get_state(&encoder, &encoderState);
+    //calculate total distance since last reset
+    return encoderState.position; 
+}
+
+
+//========================
+//=== encoder_getLenMm ===
+//========================
+//get current length in Mm since last reset
+int encoder_getLenMm(){
+    return (float)encoder_getSteps() * 1000 / ENCODER_STEPS_PER_METER; 
+}
+
+
+//=======================
+//==== encoder_reset ====
+//=======================
+//reset counted steps / length to 0
+void encoder_reset(){
+    rotary_encoder_reset(&encoder);
+    return;
+}    

main/encoder.hpp

@@ -0,0 +1,38 @@
+/* in this file all used functions from original rotary_encoder.h library are wrapped with custom functions to reduce global variables and duplicate code
+*/
+//TODO create a cpp class for an encoder?
+#pragma once
+extern "C" {
+#include <freertos/task.h>
+}
+
+
+
+//----------------------------
+//----- global variables -----
+//----------------------------
+//TODO ignore global encoder queue, since it is not used?
+extern QueueHandle_t encoder_queue; //encoder event queue
+
+
+//-------------------------
+//------- functions -------
+//-------------------------
+
+//--- encoder_init ---
+//init encoder
+QueueHandle_t encoder_init();
+
+//--- encoder_getSteps ---
+//get steps counted since last reset
+int encoder_getSteps();
+
+
+//--- encoder_getLenMm ---
+//get current length in Mm since last reset
+int encoder_getLenMm();
+
+    
+//--- encoder_reset ---
+//reset counted steps / length to 0
+void encoder_reset();

main/global.cpp

@@ -0,0 +1,23 @@
+#include "global.hpp"
+#include "config.h"
+
+
+//--- inputs ---
+//create and configure objects for evaluated switches
+//gpio_evaluatedSwitch sw_gpio_39(GPIO_NUM_39, false, true); //pullup false, INVERTED (switch to 3V3, pulldown on pcb soldered)
+gpio_evaluatedSwitch sw_gpio_34(GPIO_NUM_34, false, true); //pullup false, INVERTED (switch to 3V3, pulldown on pcb soldered)
+gpio_evaluatedSwitch sw_gpio_32(GPIO_NUM_32, true, false); //pullup true, not inverted (switch to GND, internal pullup used)
+gpio_evaluatedSwitch sw_gpio_33(GPIO_NUM_33, true, false); //pullup true, not inverted (switch to GND, internal pullup used)
+gpio_evaluatedSwitch sw_gpio_25(GPIO_NUM_25, true, false); //pullup true, not inverted (switch to GND, internal pullup used)
+gpio_evaluatedSwitch sw_gpio_26(GPIO_NUM_26, true, false); //pullup true, not inverted (switch to GND, internal pullup used)
+gpio_evaluatedSwitch sw_gpio_14(GPIO_NUM_14, true, false); //pullup true, not inverted (switch to GND, internal pullup used)
+
+//--- switches connected to 4 sw to analog stripboard ---
+//evaluated switches with function to obtain the current input state instead of gpio
+gpio_evaluatedSwitch sw_gpio_analog_0(&switchesAnalog_getState_sw0);
+gpio_evaluatedSwitch sw_gpio_analog_1(&switchesAnalog_getState_sw1);
+gpio_evaluatedSwitch sw_gpio_analog_2(&switchesAnalog_getState_sw2);
+gpio_evaluatedSwitch sw_gpio_analog_3(&switchesAnalog_getState_sw3);
+
+//create buzzer object with no gap between beep events
+buzzer_t buzzer(GPIO_BUZZER, 0);

main/global.hpp

@@ -0,0 +1,33 @@
+#pragma once
+
+extern "C" {
+#include "driver/adc.h"
+}
+#include "gpio_evaluateSwitch.hpp"
+#include "buzzer.hpp"
+#include "switchesAnalog.hpp"
+
+//note: in the actual code macro variables to these objects from config.h are used as the objects names
+
+//============================
+//===== global variables =====
+//============================
+//create global evaluated switch objects for all available pins
+//--- switches on digital gpio pins ---
+//extern gpio_evaluatedSwitch sw_gpio_39;
+extern gpio_evaluatedSwitch sw_gpio_34;
+extern gpio_evaluatedSwitch sw_gpio_32;
+extern gpio_evaluatedSwitch sw_gpio_33;
+extern gpio_evaluatedSwitch sw_gpio_25;
+extern gpio_evaluatedSwitch sw_gpio_26;
+extern gpio_evaluatedSwitch sw_gpio_14;
+
+//--- switches connected to 4-sw-to-analog stripboard ---
+extern gpio_evaluatedSwitch sw_gpio_analog_0;
+extern gpio_evaluatedSwitch sw_gpio_analog_1;
+extern gpio_evaluatedSwitch sw_gpio_analog_2;
+extern gpio_evaluatedSwitch sw_gpio_analog_3;
+
+
+//create global buzzer object
+extern buzzer_t buzzer;

main/guide-stepper.cpp

@@ -0,0 +1,467 @@
+extern "C"
+{
+#include <stdio.h>
+#include "freertos/FreeRTOS.h"
+#include "freertos/task.h"
+#include "esp_log.h"
+#include "driver/adc.h"
+#include "freertos/queue.h"
+#include "freertos/semphr.h"
+}
+
+#include "stepper.hpp"
+#include "config.h"
+#include "global.hpp"
+#include "guide-stepper.hpp"
+#include "encoder.hpp"
+#include "shutdown.hpp"
+
+
+//macro to get smaller value out of two
+#define MIN(a, b) (((a) < (b)) ? (a) : (b))
+
+//---------------------
+//--- configuration ---
+//---------------------
+//also see config.h 
+//for pin definitions and guide parameters
+
+// configure testing modes
+#define STEPPER_TEST_TRAVEL 65     // mm
+// speeds for testing with potentiometer (test task only)
+#define SPEED_MIN 2.0   // mm/s
+#define SPEED_MAX 70.0  // mm/s
+//note: actual speed is currently defined in config.h with STEPPER_SPEED_DEFAULT
+//simulate encoder with reset button to test stepper ctl task
+//note STEPPER_TEST has to be defined as well
+//#define STEPPER_SIMULATE_ENCODER
+
+#define PI 3.14159
+//#define POS_MAX_STEPS GUIDE_MAX_MM * STEPPER_STEPS_PER_MM  //note replaced with posMaxSteps
+#define POS_MIN_STEPS GUIDE_MIN_MM * STEPPER_STEPS_PER_MM
+
+
+//----------------------
+//----- variables ------
+//----------------------
+typedef enum axisDirection_t {AXIS_MOVING_LEFT = 0, AXIS_MOVING_RIGHT} axisDirection_t;
+
+static const char *TAG = "stepper-ctrl"; //tag for logging
+
+static axisDirection_t currentAxisDirection = AXIS_MOVING_RIGHT;
+static uint32_t posNow = 0;
+
+static int layerCount = 0;
+
+// queue for sending commands to task handling guide movement
+static QueueHandle_t queue_commandsGuideTask;
+
+// mutex to prevent multiple axis to config variables also accessed/modified by control task
+SemaphoreHandle_t configVariables_mutex = xSemaphoreCreateMutex();
+
+// configured winding width: position the axis returns again in steps
+static uint32_t posMaxSteps = GUIDE_MAX_MM * STEPPER_STEPS_PER_MM; //assign default width
+
+
+//----------------------
+//----- functions ------
+//----------------------
+
+//=============================
+//=== guide_getAxisPosSteps ===
+//=============================
+// return local variable posNow
+// needed at shutdown detection to store last axis position in nvs
+int guide_getAxisPosSteps(){
+    return posNow;
+}
+
+
+//=============================
+//=== guide_setWindingWidth ===
+//=============================
+// set custom winding width (axis position the guide returns in mm)
+void guide_setWindingWidth(uint8_t maxPosMm)
+{
+    if (xSemaphoreTake(configVariables_mutex, portMAX_DELAY) == pdTRUE) // mutex to prevent multiple access by control and stepper-ctl task
+    {
+        posMaxSteps = maxPosMm * STEPPER_STEPS_PER_MM;
+        ESP_LOGI(TAG, "set winding width / max pos to %dmm", maxPosMm);
+        xSemaphoreGive(configVariables_mutex);
+    }
+}
+
+
+//=======================================
+//=== guide_targetLength2WindingWidth ===
+//=======================================
+// calculate dynamic winding width in mm from cable length in mm
+uint8_t guide_targetLength2WindingWidth(int lenMm)
+{
+#ifdef DYNAMIC_WINDING_WIDTH_ENABLED
+    uint8_t width;
+    //--- config ---
+    // define thresholds for winding widths according to target length:
+    if (lenMm <= 5000) // 0-5m
+        width = 15;
+    else if (lenMm <= 10000) // 6-10m
+        width = 25;
+    else if (lenMm <= 15000) // 11-15m
+        width = 30;
+    else if (lenMm <= 25000) // 16-25m
+        width = 65;
+    else // >25m
+        width = GUIDE_MAX_MM;
+    ESP_LOGW(TAG, "length2width: calculated windingWidth=%dmm from targetLength=%dm", width, lenMm);
+    return width;
+#else
+    ESP_LOGD(TAG, "length2width: dynamic windingWidh not enabled, stay at GUIDE_MAX=%d", GUIDE_MAX_MM);
+    return GUIDE_MAX_MM;
+#endif
+//TODO update winding width here as well already?
+}
+
+
+//=============================
+//=== guide_getWindingWidth ===
+//=============================
+// get currently configured winding width (axis position at which the guide returns in mm)
+uint8_t guide_getWindingWidth()
+{
+    if (xSemaphoreTake(configVariables_mutex, portMAX_DELAY) == pdTRUE) // mutex to prevent multiple access by control and stepper-ctl task
+    {
+        uint8_t returnValue = posMaxSteps / STEPPER_STEPS_PER_MM;
+        xSemaphoreGive(configVariables_mutex);
+        return returnValue;
+    }
+    return 0;
+}
+
+
+//==========================
+//==== guide_moveToZero ====
+//==========================
+//tell stepper-control task to move cable guide to zero position
+void guide_moveToZero(){
+    bool valueToSend = true; // or false
+    xQueueSend(queue_commandsGuideTask, &valueToSend, portMAX_DELAY);
+    ESP_LOGI(TAG, "sending command to stepper_ctl task via queue");
+}
+
+
+//---------------------
+//---- travelSteps ----
+//---------------------
+//move axis certain Steps (relative) between left and right or reverse when negative
+void travelSteps(int stepsTarget){
+	//TODO simplify this function, one simple calculation of new position?
+	//with new custom driver no need to detect direction change
+
+    // cancel when width is zero or no steps received
+    if (posMaxSteps == 0 || stepsTarget == 0){
+        ESP_LOGD(TAG, "travelSteps: MaxSteps or stepsTarget = 0 -> nothing to do");
+        return;
+    }
+	
+    int stepsToGo, remaining;
+
+    stepsToGo = abs(stepsTarget);
+
+    // invert direction in reverse mode (cable gets spooled off reel)
+    if (stepsTarget < 0) {
+    currentAxisDirection = (currentAxisDirection == AXIS_MOVING_LEFT) ? AXIS_MOVING_RIGHT : AXIS_MOVING_LEFT; //toggle between RIGHT<->Left
+    }
+
+    while (stepsToGo != 0){
+        //--- currently moving right ---
+        if (currentAxisDirection == AXIS_MOVING_RIGHT){               //currently moving right
+        if (xSemaphoreTake(configVariables_mutex, portMAX_DELAY) == pdTRUE) { //prevent multiple acces on posMaxSteps by control-task
+            remaining = posMaxSteps - posNow;     //calc remaining distance fom current position to limit
+            if (stepsToGo > remaining){             //new distance will exceed limit
+                stepper_setTargetPosSteps(posMaxSteps);        //move to limit
+				stepper_waitForStop(1000);
+                posNow = posMaxSteps;
+                currentAxisDirection = AXIS_MOVING_LEFT;            //change current direction for next iteration
+                //increment/decrement layer count depending on current cable direction
+                layerCount += (stepsTarget > 0) - (stepsTarget < 0);
+                if (layerCount < 0) layerCount = 0; //negative layers are not possible
+                stepsToGo = stepsToGo - remaining;  //decrease target length by already traveled distance
+                ESP_LOGI(TAG, " --- moved to max -> change direction (L) --- \n ");
+            }
+            else {                                  //target distance does not reach the limit
+                stepper_setTargetPosSteps(posNow + stepsToGo);   //move by (remaining) distance to reach target length
+                ESP_LOGD(TAG, "moving to %d\n", posNow+stepsToGo);
+                posNow += stepsToGo;
+                stepsToGo = 0;                      //finished, reset target length (could as well exit loop/break)
+            }
+            xSemaphoreGive(configVariables_mutex);
+        }
+        }
+
+        //--- currently moving left ---
+        else if (currentAxisDirection == AXIS_MOVING_LEFT){
+            remaining = posNow - POS_MIN_STEPS;
+            if (stepsToGo > remaining){
+                stepper_setTargetPosSteps(POS_MIN_STEPS);
+				stepper_waitForStop(1000);
+                posNow = POS_MIN_STEPS;
+                currentAxisDirection = AXIS_MOVING_RIGHT; //switch direction
+                //increment/decrement layer count depending on current cable direction
+                layerCount += (stepsTarget > 0) - (stepsTarget < 0);
+                if (layerCount < 0) layerCount = 0; //negative layers are not possible
+                stepsToGo = stepsToGo - remaining;
+                ESP_LOGI(TAG, " --- moved to min -> change direction (R) --- \n ");
+            }
+            else {
+                stepper_setTargetPosSteps(posNow - stepsToGo);           //when moving left the coordinate has to be decreased
+                ESP_LOGD(TAG, "moving to %d\n", posNow - stepsToGo);
+                posNow -= stepsToGo;
+                stepsToGo = 0;
+            }
+        }
+    }
+
+    // undo inversion of currentAxisDirection after reverse mode is finished
+    if (stepsTarget < 0) {
+    currentAxisDirection = (currentAxisDirection == AXIS_MOVING_LEFT) ? AXIS_MOVING_RIGHT : AXIS_MOVING_LEFT; //toggle between RIGHT<->Left
+    }
+
+    return;
+}
+
+
+//------------------
+//---- travelMm ----
+//------------------
+//move axis certain Mm (relative) between left and right or reverse when negative
+void travelMm(int length){
+    travelSteps(length * STEPPER_STEPS_PER_MM);
+}
+
+
+//----------------------
+//---- init_stepper ----
+//----------------------
+//initialize/configure stepper instance
+void init_stepper() {
+	//TODO unnecessary wrapper?
+    ESP_LOGW(TAG, "initializing stepper...");
+	stepper_init();
+    // create queue for sending commands to task handling guide movement
+    // currently length 1 and only one command possible, thus bool
+    queue_commandsGuideTask = xQueueCreate(1, sizeof(bool));
+}
+
+
+//--------------------------
+//--- updateSpeedFromAdc ---
+//--------------------------
+//function that updates speed value using ADC input and configured MIN/MAX - used for testing only
+void updateSpeedFromAdc() {
+    int potiRead = gpio_readAdc(ADC_CHANNEL_POTI); //0-4095 GPIO34
+    double poti = potiRead/4095.0;
+    int speed = poti*(SPEED_MAX-SPEED_MIN) + SPEED_MIN;
+	stepper_setSpeed(speed);
+    ESP_LOGW(TAG, "poti: %d (%.2lf%%), set speed to: %d", potiRead, poti*100, speed);
+}
+
+
+
+//============================
+//==== TASK stepper_test =====
+//============================
+//test axis without using encoder input
+#ifndef STEPPER_SIMULATE_ENCODER
+void task_stepper_test(void *pvParameter)
+{
+	stepper_init();
+	while(1){
+		vTaskDelay(20 / portTICK_PERIOD_MS);
+
+		//------ handle switches ------
+		//run handle functions for all switches
+		SW_START.handle();
+		SW_RESET.handle();
+		SW_SET.handle();
+		SW_PRESET1.handle();
+		SW_PRESET2.handle();
+		SW_PRESET3.handle();
+		SW_CUT.handle();
+		SW_AUTO_CUT.handle();
+
+#ifdef ONE_BUTTON_TEST //test with "reset-button" only
+        static int state = 0;
+        //cycle through test commands with one button
+		if (SW_RESET.risingEdge) {
+			switch (state){
+				case 0:
+					stepper_setTargetPosMm(50);
+					//stepper_setTargetPosSteps(1000);
+					state++;
+					break;
+				case 1:
+					stepper_setTargetPosMm(80);
+					//stepper_setTargetPosSteps(100);
+					state++;
+					break;
+				case 2:
+					stepper_setTargetPosMm(20);
+					//stepper_setTargetPosSteps(100);
+					state++;
+					break;
+				case 3:
+					stepper_setTargetPosMm(60);
+					//stepper_setTargetPosSteps(2000);
+					state = 0;
+					break;
+			}
+		}
+#else //test with all buttons
+		if (SW_RESET.risingEdge) {
+			buzzer.beep(1, 500, 100);
+			stepper_setTargetPosMm(0);
+		}
+		if (SW_PRESET1.risingEdge) {
+			buzzer.beep(1, 200, 100);
+			stepper_setTargetPosMm(50);
+		}
+		if (SW_PRESET2.risingEdge) {
+			buzzer.beep(2, 200, 100);
+			stepper_setTargetPosMm(75);
+		}
+		if (SW_PRESET3.risingEdge) {
+			buzzer.beep(3, 200, 100);
+			stepper_setTargetPosMm(100);
+		}
+#endif
+	}
+}
+#endif //end SIMULATE_ENCODER
+
+
+
+//============================
+//===== TASK stepper_ctl =====
+//============================
+//task controlling the linear axis guiding the cable according to wire length spooled
+#ifdef STEPPER_SIMULATE_ENCODER
+void task_stepper_test(void *pvParameter)
+#else
+void task_stepper_ctl(void *pvParameter)
+#endif
+{
+    //-- variables --
+    static int encStepsPrev = 0; //measured encoder steps at last run
+    static double travelStepsPartial = 0; //store resulted remaining partial steps last run
+
+    //temporary variables for calculating required steps, or logging
+    int encStepsNow = 0; //get curretly measured steps of encoder
+    int encStepsDelta = 0; //encoder steps changed since last iteration
+
+    double cableLen = 0;
+    double travelStepsExact = 0; //steps axis has to travel
+    int travelStepsFull = 0;
+    double travelMm = 0;
+    double turns = 0;
+    float currentDiameter;
+
+
+
+    //initialize stepper at task start
+    init_stepper();
+    //define zero-position
+    // use last known position stored at last shutdown to reduce time crashing into hardware limit
+    int posLastShutdown = nvsReadLastAxisPosSteps();
+    if (posLastShutdown >= 0)
+    { // would be -1 when failed
+        ESP_LOGW(TAG, "auto-home: considerting pos last shutdown %dmm + tolerance %dmm",
+        posLastShutdown / STEPPER_STEPS_PER_MM, 
+        AUTO_HOME_TRAVEL_ADD_TO_LAST_POS_MM);
+        // home considering last position and offset, but limit to max distance possible
+        stepper_home(MIN((posLastShutdown/STEPPER_STEPS_PER_MM + AUTO_HOME_TRAVEL_ADD_TO_LAST_POS_MM), MAX_TOTAL_AXIS_TRAVEL_MM));
+    }
+    else { // default to max travel when read from nvs failed
+        stepper_home(MAX_TOTAL_AXIS_TRAVEL_MM);
+    }
+
+    //repeatedly read changes in measured cable length and move axis accordingly
+    while(1){
+
+        // guide is disabled when posMaxSteps is zero:
+        if (posMaxSteps == 0)
+        {
+            // move to starting position
+            stepper_setTargetPosSteps(0);
+            vTaskDelay(1000 / portTICK_PERIOD_MS);
+            ESP_LOGD(TAG, "posMaxSteps is zero -> guide disabled, doing nothing");
+            // stop loop iteration
+            continue;
+        }
+
+#ifdef STEPPER_SIMULATE_ENCODER
+		//TESTING - simulate encoder using switch
+		SW_RESET.handle();
+		//note 
+		if (SW_RESET.risingEdge) encStepsNow += 500;
+#else
+        //get current length
+        encStepsNow = encoder_getSteps();
+#endif
+
+        // move to zero and reset if command received via queue
+        bool receivedValue;
+        if (xQueueReceive(queue_commandsGuideTask, &receivedValue, 0) == pdTRUE)
+        {
+            // Process the received value
+            // TODO support other commands (currently only move to zero possible)
+            ESP_LOGW(TAG, "task: move-to-zero command received via queue, starting move, waiting until position reached");
+            stepper_setTargetPosMm(0);
+            stepper_waitForStop();
+            //reset variables -> start tracking cable movement starting from position zero
+            // ensure stepsDelta is 0
+            encStepsNow = encoder_getSteps();
+            encStepsPrev = encStepsNow;
+            travelStepsPartial = 0;
+            // set locally stored axis position and counted layers to 0 (used for calculating the target axis coordinate and steps)
+            posNow = 0;
+            layerCount = 0;
+            currentAxisDirection = AXIS_MOVING_RIGHT;
+            ESP_LOGW(TAG, "at position 0, reset variables, resuming normal cable guiding operation");
+        }
+
+        //calculate change
+        encStepsDelta = encStepsNow - encStepsPrev;
+        //check if reset happend without moving to zero before - resulting in huge diff
+        if (encStepsDelta != 0 && encStepsNow == 0){  // this should not happen and causes weird movement
+            ESP_LOGE(TAG, "encoder steps changed to 0 (reset) without previous moveToZero() call, resulting in stepsDelta=%d", encStepsDelta);
+        }
+
+        //read potentiometer and normalize (0-1) to get a variable for testing
+        //float potiModifier = (float) gpio_readAdc(ADC_CHANNEL_POTI) / 4095; //0-4095 -> 0-1
+        //ESP_LOGI(TAG, "current poti-modifier = %f", potiModifier);
+
+        //calculate steps to move
+        cableLen = (double)encStepsDelta * 1000 / ENCODER_STEPS_PER_METER;
+        //effective diameter increases each layer
+        currentDiameter = D_REEL + LAYER_THICKNESS_MM * 2 * layerCount;
+        turns = cableLen / (PI * currentDiameter);
+        travelMm = turns * D_CABLE;
+        travelStepsExact = travelMm * STEPPER_STEPS_PER_MM  +  travelStepsPartial; //convert mm to steps and add not moved partial steps
+        travelStepsPartial = 0;
+        travelStepsFull = (int)travelStepsExact;
+
+        //move axis when ready to move at least 1 full step
+        if (abs(travelStepsFull) > 1){
+            travelStepsPartial = fmod(travelStepsExact, 1); //save remaining partial steps to be added in the next iteration
+            ESP_LOGI(TAG, "dCablelen=%.2lf, dTurns=%.2lf, travelMm=%.3lf, StepsExact: %.3lf, StepsFull=%d, StepsPartial=%.3lf, totalLayerCount=%d, diameter=%.1f", cableLen, turns, travelMm, travelStepsExact, travelStepsFull, travelStepsPartial, layerCount, currentDiameter);
+            ESP_LOGD(TAG, "MOVING %d steps", travelStepsFull);
+            travelSteps(travelStepsExact);
+            encStepsPrev = encStepsNow; //update previous length
+        }
+        else {
+            //TODO use encoder queue to only run this check at encoder event?
+            vTaskDelay(5);
+        }
+		vTaskDelay(5 / portTICK_PERIOD_MS);
+    }
+}

main/guide-stepper.hpp

@@ -0,0 +1,30 @@
+#pragma once
+
+//task that initializes and controls the stepper motor
+//current functionality: 
+//  - automatically auto-homes
+//  - moves left and right repeatedly
+//  - updates speed from potentiometer each cycle
+void task_stepper_test(void *pvParameter);
+
+//task that initializes and controls the stepper motor
+//  - moves stepper according to encoder movement
+void task_stepper_ctl(void *pvParameter);
+
+
+//tell stepper-control task to move cable guide to zero position
+void guide_moveToZero();
+
+
+// return local variable posNow that stores the current position of cable guide axis in steps
+// needed by shutdown to store last axis position in nvs
+int guide_getAxisPosSteps();
+
+// set custom winding width (axis position the guide returns in mm)
+void guide_setWindingWidth(uint8_t maxPosMm);
+
+// get currently configured winding width (axis position the guide returns in mm)
+uint8_t guide_getWindingWidth();
+
+// calculate dynamic winding width in mm from cable length in mm according to fixed thresholds
+uint8_t guide_targetLength2WindingWidth(int lenMm);