autohelm 800 refit with pypilot motor controller

[ironman]

1) I would like to reuse the autohelm buttons connected to the arduino to send back some basic command to pypilot like engage/disengage or tack. Can pypilot accept that kind of command from the arduino? if yes, where can i find the command frames?

2) I was thinking using an isolated RS422 link between open plotter and the arduino. But i also may consider using a low power wierless connection like blutooth or ziegbee reducing wiering and garanteeing isolation. does someone have feedback on wiereless communication between pypilot and the motor controller?

1) I built both tinypilot (pizero) and the arduino in a former ST2000+, see this post. The keys were mapped to the pizero with a piece of custom code I added to the tinypilot image, the code is in github. The pypilot is connected to the opencpn plugin in openplotter through wifi. This was a lot of work.

2) For short distances you can even connect them only though an optocoupler/level shifter. Remember the link between pi and arduino is bi-directional. But with openplotter outside the autohelm, you'd also connect the keys back to the openplotter... I'm not aware of anyone having done this wirelessly.