I haven't personally used this feature of PJON, but they have an apparent way of communicating bidirectionally with a single LED on each side. The one wire soft

I haven't personally used this feature of PJON, but they have an apparent way of communicating bidirectionally with a single LED on each side. The one wire software bit bang method worked for me though. https://www.pjon.org/AnalogSampling.php https://www.pjon.org/AnalogSampling.php