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rpi-interface-board/README.md
jonny b7e05627ea init, Add README with notes and ideas
2024-10-17 16:55:31 +02:00

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A Raspberry Pi-compatible PCB that extends the GPIO header with protected I/O, relays, and various features for versatile use in prototyping and project development.

Notes:

Name

  • Pi-multipurpose-Adapter

  • Pi-multi-function-adapter

  • Pi-extension-board

  • universal-Pi-interface-board

  • pi-peripheral-interface

  • raspberry-extension-board

  • Pi-protected-connection-hub

RPI Specs (Zero, 3+)

  • Available (old) Pi: Raspberry Pi 2 Modell B v1.1

  • GPIO

    • Low: 0.9V
    • High: 1.6V
    • Input current: 5uA
    • Input capacitance: 5pF
    • Output Current +-17mA
    • Pullup / Pulldown 50-65k

  • EEPROM GPIO0 GPIO1, leave unused

Feature Ideas

Supply

  • Input protection

    • TVS
    • reverse polarity
    • Fuse
    • buffer

  • Pass through power supply

  • 3.3V, 5V, 12V, 24V Regulator

  • power by barrel connector (24V 3A)

  • power by usb

    • Switch between power by USB or power supply?

  • power by battery

    • liion cell connector
    • BMS / charge controller

IO

  • Input

    • GPIO
      • voltage protection
        • 330R, Z
      • wide voltage range 1.6-24V
      • Low pass filter
      • Optocoupler input
    • ADC
      • external IC
      • multiplexer?
      • protection
      • scale input voltage
        • fixed inputs: 24V 12V 5V 3.3V ?
        • trim potentiometer?

  • Output

    • Relay
    • Mosfet
    • Optocoupler output
    • GPIO with over current protection
    • GPIO level shift (24V output)
    • PWM pins
    • shift register
    • DAC

  • LEDS indicate I/O state

  • Testpoints

  • ESD protection

Bus

  • UART/RS485
  • RS232 Connector
  • I2C Pullup
  • SPI
  • CAN
  • Serial to usb (if Arduino)
  • OWB default GPIO4

UI

  • Input
    • Buttons
    • DIP switches?
    • Temperature sensor
    • Encoder
    • Potentiometer
  • Output
    • Display
    • Buzzer
    • LEDS

Mechanical

  • Barrel plug (24V 3A supply)
  • Screw terminals / spring loaded?
  • pin header angled?
  • pin header for extension
  • pass through all pins?

Housing

  • RPI ports
  • banana sockets for power out
  • screw terminal exposed
  • buttons, leds: need to open up?
  • BNC? []

Other

  • Extension board with multiplexer
  • Breadboard compatible?
  • SD Card
  • Onboard MCU for standalone use?
  • separate bought MCU via i2c for additional GPIO, DAC, ADC in one