This was made to monitor if a machine is still turned on or properly running, as it is hard to rely on software on the host machine to send a notification if it unexpectedly turns off or kernel panics, as the computer is still turned on after a kernel panic.
heartbeat_client is required on the host machine for this to work. This works by the client constantly sending every second to the microcontroller. If it doesn't receive data after a second, it will turn on all LEDs and send a ntfy notification.
I understand that it is bad to block the main loop, but the code currently does nothing during timeout and this keeps the code simpler.
This project uses PlatformIO VSCode extension.
Include your microcontroller in the platformio.ini file.
Build and flash from the extension.