In my circuit I have a relay that will turn on some light bulbs this is my circuit:
This is working fine, but because of security measures I need to add a mechanical switch to be able to turn on and off whenever needed. This is the circuit I'm using for this configuration:
This circuit also works fine, the lamp is turned on and off by changing either switches but the Arduino loses track of the status of the lamp. The only thing it knows is if the relay is on or off.
Is there a simple way to tell when the lamp is on?