How's the roller door work?
If you open up the circuit there has to be a relay to open the door with, well, you could reroute those (gnd/+) to the arduino and then check the voltage from that if the signal >5v use a voltage divider.
How's the roller door work?
If you open up the circuit there has to be a relay to open the door with, well, you could reroute those (gnd/+) to the arduino and then check the voltage from that if the signal >5v use a voltage divider.