I have a bunch of sonoff 4ch installed inside the wall behind the wall plate wired up on 3 of the channels to control the 3 speeds of my ceiling fan and the forth channel to control the light for that room. In order to make my dumb fan smart using this method has meant I have lost the ability to use the standard wall switch. I have replacements with voice control, hadashboard and also a xiaomi push button switch programmed to toggle through the fan speeds. This does not meet wife approval who wants to use the standard switch so I have one of the gpio hockey up for the standard light switch but can’t find a lot of information regarding where the others are for the remaining 3 does anyone know where they are located on the sonoff board? I have no problems with needing to solder them if required.
I am not sure that the 4ch has any open pins. Between the mode switch time switch and RF receiver, the 4 buttons and relay outputs.
I didn’t see anything on the pcb.
I would post the question on the Sonoff Forum
Won’t the buttons show you where to connect?