About

Ever need a serial port far away from your Raspberry Pi? Wish you could use WiFi to talk to a serial device without having to run a wire? This project is for you.

Installation

sudo npm i -g remote-serial-pico
remote-serial-pico i

Now a server is running on the Pi. If you plug in a Pico to the USB it will install the client code on the pico within 6 sec and make it a remote serial port.

/dev/pts/pty1

It's that easy to setup a remote serial port. Each time you plug in a pico, it will be the next ptyN on the list.

If you haven't already installed npm:

sudo apt update
sudo apt install nodejs npm

Background

Designed to facilitate communication between a remote device (such as a Raspberry Pi) and a device connected via serial to the Pico. It leverages TCP/IP networking to bridge data exchange between the Pico's serial interface and a networked environment. Extend this project using either the node-red-bridge or homebridge-tcp-smarthome.

Pico on-board LED status

• LED blinks repeatedly during the WiFi connection process. Upon successful connection it turns off.
• LED switches on again when connected to the TCP server.
• LED blinks once upon receiving a command either from TCP server or a serially connected device.
• LED turns off when disconnected from the TCP server.

Project Details

• Curious about PtyServer?

  • Detects Pico clients upon receiving first packet with pico_{N}, and creates a pseudo terminal(pty) for each Pico.
  • Sends data available in pty to the respective Pico.
  • Writes data received from Pico into corresponding pty.
  • Log the commands and responses for each pico; check out the log:

    tail -f /tmp/smartHome.log
    

• Wondering how plugging Pico into the Pi installs client code in Pico?

  • The udev rule (99-pico.rules) watches Pi's USB port for Pico connection.
  • When a Pico is connected, it triggers another script PicoScriptDeployer.py to run on Pi.

• And what exactly does PicoScriptDeployer do?

  • It fetches wifi-ssid, password, IP, Pico-Serial-ID and updates the corresponding credentials on config.json. You can also manually update it.
  • Deploys main.py and config.json to the most recently connected pico.
  • You can observe the deployer log:

    tail -f /tmp/deployer.log
    

• Now, what's the role of the main code in Pico?

  • Retrieves the network credentials and server details from the config.json.
  • Upon TCP connection, sends its Serial-ID to the Pi in the first packet.
  • Continuously checks for data in TCP and Serial; if it receives data from either, it sends that data to the other.

Visual Overview

• Checkout detailed diagram.

  

Credits

Special thanks to Medical Informatics Engineering for their support throughout the development of this project, especially to Doug Horner for his invaluable guidance.