ConnectCam - Minimialistic webcam manager for Prusa Connect

Upgrading from a Prusa i3 MK3S+ to a Prusa MK4, I lost the great feature of connecting USB web cameras to the Raspberry Pi Zero I had running PrusaLink. This utility aims to be a solution to that problem.

Simply take your old PrusaLink-Pi, give it a fresh installation of Raspberry Pi OS Lite, connect your webcam(s), install ConnectCam, and your cameras are back in Prusa Connect!

Requirements

• A Linux-based OS, like Raspberry Pi OS (ConnectCam is using V4L2 for basically everything)
• Python (3.1+)
• Python libraries:
  • On Raspberry Pi OS, these apt packages:
    sudo apt install python3-toml python3-requests python3-v4l2
    (All of these are installed by default in Raspberry Pi OS Lite.)
  • On other OS, these pip packages:
    pip install toml requests v4l2-python3

Installation

1. Run v4l2-ctl --list-devices to find your connected cameras.
   Example:

   UVC Camera (046d:0825) (usb-20980000.usb-1.1):
           /dev/video0
           /dev/video1
           /dev/media0
   
   Full HD webcam: Full HD webcam (usb-20980000.usb-1.3):
           /dev/video2
           /dev/video3
           /dev/media1
   

2. Copy config.toml.example to config.toml and edit to your needs, adding your cameras to Prusa Connect to generate the needed tokens.
   Example:

   refresh_rate = 10 # Seconds between each snapshot
   
   [[camera]]
   name = "Full HD webcam: Full HD webcam"
   token = "T0k3n0N3"
   
   [[camera]]
   name = "UVC Camera (046d:0825)"
   token = "T0k3n7W0"
   

   (There are more settings available, see config.toml.example for more info.)
3. Run ./connectcam.py -vo config.toml to make sure your config works.
4. Run ./install_service.sh config.toml to install ConnectCam as a system service, starting automatically on boot.
5. Done!

Limitations

To keep the code small, and required libraries to the minimum, ConnectCam (currently) only supports MJPEG capable web cameras (unlike Prusa Link, which also supports YUYV). This works for my two cameras (Logitech C270 and Trust Trino HD). Experiments with YUYV just seemed to hang for some unknown reason when trying to speak to more than one camera at a time, so I gave that up quite quickly.

Since I don't own any Pi Camera, I am unsure how this limitation affects them. Pull Requests are more than welcome, though! :)