a 100 μF electrolytic capacitor

an audio output transformer, such as RadioShack part #273-1380

an SPDT relay, such as RadioShack part #275-0248

a tilt switch (I’ve used a mercury bubble switch—it looks like a fat Christmas tree light bulb in the picture—but these are pretty rare nowadays. Any tilt switch, such as Mouser part #107-2008, will do.)

22- or 24-gauge insulated wire, either stranded or solid-core

a 9-volt battery and a battery clip

aluminum foil

a small box (A jewelry gift box is ideal.)

electrical tape

(optional) glue or double-sided tape