FFor a rudimentary Piezo pick up for tuning purposes. Get a piezo buzzer at radio shack and carefully take it apart till the wafer is free and the rest is junque. Solder a piece of 2 strand speaker wire, one strand in the center of the wafer, one strand on the edge. Care full not to cross over the isolator. Besure to leave the smooth side smooth. On the smooth side add some Barcus Barry stickum. at the other end of the 2 strand wire. wire in a 1/8 " Plug lack also from radio shack. Plug your tuner into this mess and stick the poezo on the harp, dulcimer, guitar, what ever. The piezo effect is strong enough to give you a solid pick up for the tuner.

I have also made very successfull piezo pick ups this way.

From an old article on pick ups in guitar player about 12-15 years ago.

Don