I have a controller with 3 pins for a sensor input. Positive, Negative, and Signal. I placed a wire on just the Signal. The controller reads out the varying voltage across the signal wire/pin. To the wire I attached a piece of Aluminum. Every time I touched the aluminum with my finger the voltage would go from 0v to some other value such as 0.3-0.6v Same thing when I touched it with a metal object. Nothing happen however when I touched it with paper or plastic. Is this an induction sensor? I just need to be sure. Thanks in advance.