@tnick STM32F1 2019.12.8 (stm32duino) is the version that was active when the latest MySensors release was made. Later versions may or may not work; nobody would know until they tried.
I want to thank @FcNanoLed. I had long thought about a serial gateway. This would be a way to add I/O to a linux computer. In the process of trying to help, I built up a linux machine running virtual box. In the virtual machine I ran Home Assistant The not well documented part of that was to connect the USB port of the computer to the virtual machine (settings-->USB-->USB Device Filters) (note that one can buy a refurbished PC for about the same price as an equivalently configured RPi)
So thanks for the inspiration!
You write "...clicking is heard..." Is that a single click or a click click click ...?
After getting the LOW signal, wait a period of time and if it's still low, send the message that there is a flame. Likewise for a HIGH signal.
Perhaps instead of a relay, an opto-isolator?
@mvader Turn the time delay adjustment preset on your PIR module to the minimum.. Now try it.. You will not get a continuous output..Also, prepare the circuit using a long wire from the back to the sensor of your module.
