In this short instructable I will demonstrate how I harvest Piezo elements from dollar store window alarms. Why you ask? Because these things are awesome pickups for guitars or any other acoustic instrument you are building. Also I am doing this to answer a question from a viewer of one of my instructables https://www.instructables.com/id/How-to-build-an-Electric-Guitar/.
Step 1: Take Things Apart
Open the battery compartment and remove the screw that holds everything together. Pull the back off. Pull the circuit board out and isolate the wires to the piezo.
Step 2: Isolate the Part You Want.
In the movies they would be sweating over which wire to cut first, no such issue here, cut them both at the same time.
Step 3: Remove the Part You Want.
OK, this is the only tricky bit, cutting the plastic housing to get the element out without bending it. A little bend won't hurt anything but you don't want to crack that white disc in the middle.