Evan Grove revisits a surplus store and buys a “clap switch” circuit board for fifty cents. In the US, a clap switch was marketed commercially as a Clapper.

What’s a Clapper?

A little history for those who either aren’t from the US, or who are too young to have heard of these: The Clapper is a goofy gadget that rose to notoriety in the US in the 1980s. Its aggressive TV marketing campaign put a catchy jingle in millions of American living rooms. The unlucky souls who actually bought the things discovered they were more of a silly novelty than a useful appliance.

The goal of the Clapper was to allow you to control household electrical things by clapping. Clap twice to turn on your bedside lamp, clap twice again to shut it off. Although it was marketed as a device to control everything from lights to TVs, the Clapper was probably more effective as a device to scare pets and amuse guests.

Early versions of the Clapper were deeply flawed. According to contemporary accounts, they were much too sensitive. Even when you managed to dial in the sensitivity, they were extremely unreliable.

Evan goes through the schematic and then puts it through the test. And then works to add a digital counter circuit.

See more in the post here.