#Ludomotico has some very interesting python 'middleware' code that sits inbetween FG and Arduino and might be able to elaborate or #Bill516 on this but in the hope of developing functions other than COM's like gear down with a feedback LED that lights once it's down, or APProch that only lights when you hit the glide-slope how would this work with variables being passed to and from the properties tree through python to the Arduino? I have a little programming knowledge but I'm nowhere near what Ludomotico or Bill516 have done with their code.
Example: Hitting the APProach button (747 for example) on an Arduino interface, the arduino via python sets the property tree Approach to on (couldn't find this in the property tree wiki by the way). But, the APProach light in FG only comes on once you hit the glideslope correctly and are at a safe speed etc, so if you wanted to output the status or the Approach back to an LED on the Arduino interface to reflect being locked in or not, how would you do it? Is there a second variable or property that can be read? Same sort of thing for gear down, there is a delay while the gear comes down during which time the gear down LEDs should be off, only and if the gear gets down should the status of the gear change to all green LED.