A bit of a noob question, but Its hard to search for a solution if you dont know what to search for. ;)
I have an arduino mega, and a door sensor circuit that id like to modify so it can be triggered by the arduino.
So what I presume needs to happen, is removing the reedswitch in the sensor, and replacing it by.. something.
Does anyone know how to hook up an arduino to a switch that can open/close another circuit?