I command a double relay module (12v <-> 5V) via a #esp8266 (3.3v under #NoceMCU LUA 0.9.6 and 5.1.4). The esp8266 launches a web server and examines the request to order the two GPIO ports connected to dual channel module.
In the absence of the 12v power, everything works fine. The esp8266 control my module in real time without any problems. I can swing after many http requests I want esp8266 follows the cadence and the relay is responding.
If I turn on the power section (12v), the esp8266 launches the first http request and then it stops responding (not even a reset worked). I have to cut the power to do a reset. Even more wacky behavior, the double relay module flashes like crazy (so GPIO changes constantly of state).