For the project I am working on, i will need more GPIO pins than the Raspberry 4B provides. I'm looking into combining 2 Raspberry 4B's together to get extra GPIO pins. I also looked into port expanders however my issue is that I'll need separate control for each pin. I'm wondering if there are any good resources to chaining 2 Pi's together as a master slave system with the slave Pi just for extra GPIO pins?

  • 3
    Use an MCP23017 GPIO chip. That gives you from 16 up to 128 extra GPIOs. – Dougie Feb 22 at 16:32
  • Would this allow me to have separate control of each port? – justin Feb 22 at 18:46
  • Yes it would allow that. – Dougie Feb 23 at 9:40

Provided you can network the Pis you can use pigpio or gpiozero to control all the GPIO from a single computer.

The computer can be one of the Pis or any other networked computer.

Each Pi needs to have the pigpio daemon running.

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