The relay should have the positive wire of the device being used connected to "COM" and to

"NO" as shown in figure 2, and any digital signal pin on the arduino end (For example pin 13).

Sending a digital high or a "1" will trigger the relay. Sending a digital low or "0" will disable the

relay.

 

Figure2:Lamp Demo 

 

Please be vary carful not to play with live circuits! 120V or 220V should not be

taken lightly. Make sure the appliance to be tinckered with is unplugged from

mains. DO NOT CONNECT IT TO THE WALL WHILE MESSING WITH THE

CABLE!

Sample Code

byte relayPin[4] = {2,7,8,10};

//D2 -> RELAY1

//D7 -> RELAY2

//D8 -> RELAY3