Basically the string gets pulled and the motor spins like crazy whacking a nut on string against the pan. Simple build to do.
http://www.instructables.com/id/How-to-Make-Loud-Trip-Wire-Alarm-System/
Basically the string gets pulled and the motor spins like crazy whacking a nut on string against the pan. Simple build to do.
http://www.instructables.com/id/How-to-Make-Loud-Trip-Wire-Alarm-System/