Arduino monitor 220v ac

Hi, i have about 2 or 3 220v devices that i'm controlling with relays and it works fine

I will add a manual switch to toggle the device on and off beside the relay, the case is i want to monitor the device current status if it is turned on in case it is manual opened so i need to know how to do this keep in in mind that will be professionals will work on the 220v electrical parts, i just want to know how to technically achieve this

Have a look at “two way switching” - use one as a manual switch , the other your relay

This comes up regularly. :grinning:

It would be much more practical to connect the switch to the Arduino so that the Arduino knows both the switch position and what it has been commanded to do. To toggle, you can use a button rather than a switch as a "two way switch" arrangement is going to be somewhat confusing anyway regarding the position of the switch. The Arduino handles all the decision logic.

This avoids any problems regarding additional circuitry to monitor whether the device is on or off so minimises your interface with the power mains on both counts - input and output - is much safer and reliable.