Tag Archives: Most Useless Machine

The world’s smallest ‘most useless machine’

With the help of an ATtiny85, Maker Jeremy Cook has successfully built the world’s tiniest ‘most useless machine.’

If you’re into awesome and strange devices — and that’s a good assumption if you read this blog — chances are you’ve heard of the Useless Machine, or Leave Me Alone Box. These gadgets have a switch on top, and when it’s turned on, a “finger” extends to turn it off again. Generally this is done by an elegant circuit and a DC motor, but Maker (and frequent Atmel blogger) Jeremy Cook decided to instead cheat by using a tiny servo and microcontroller to make what he believes is the smallest “useless machine” in existence — or was before it disappeared in the void that is his garage.


To accomplish this feat, Cook soldered the incredibly tiny ATtiny85 to a coin-cell battery, a switch and a little servo motor. Pieces of MDF and polycarbonate were cut to form the body and lid of this device, and everything crudely attached together to form his “useless machine.”

When the switch is flipped, the servo is actuated to push it back into the “off” position. Though this sometimes takes more than one try, it eventually was able to accomplish its useless mission. It was definitely a shoddy prototype, but with a better mechanism, this could be a fun device to show off.


“One thing that I was proud of was using the ‘delay’ command to send a pulse to the servo used for one or two milliseconds, as explained here,” Cook writes. “This allowed for very crude pulse width modulation control with this chip. The little ATtiny doesn’t have all the features of, say, the ATmega328P used in the Arduino Uno development board, but the tiny size, and correspondingly tiny price is hard to beat for some projects!”

Interested? Head over to the Maker’s official page here, or simply watch it in action below.