This is the Clapper!
Amaze Friends with this Sound Robot
STEPPING up to a mysterious oiled paper diaphragm, the amateur electrical wizard mumbles unintelligible Greek words, suddenly claps his hands. Room lights go out almost instantly, and an oscillating electric fan throws its turbulent air blast over the faces of surprised friends.
The sound robot is made from easily obtainable materials. After the paper diaphragm is in place, a thin metal disc having soldered to it a fine wire lead is attached to the center with a drop of sealing wax. Adjust the pointed screw of the fixed contact to touch this disc at the slightest movement of the diaphragm.
Almost any magnet coil or door bell magnet having around 100 turns of No. 22 or larger magnet wire will be satisfactory for the trip relay. As the soft iron hinged armature is pulled forward by the magnet, it allows the weighted lever to drop, closing the large contacts which control the fan.