I'm no expert on this, but I believe you'll find that there's some type of transducer used to make these--something that will convert the physical motion of the part the alligator clip is touching to an electrical impulse. Radio Shack or a similar vendor should be able to identify what you need. It's probably inexpensive and small, but I bet if you study a "factory-made" alligator clip pick-up, you'll find that something is epoxied on to the clip, with the wire coming out of that "something".