What’s the most useless machine man has ever built? While that question’s answer is of course very subjective, we think we have found a very worthy candidate.
Hack A Day points us to Useless Machine Advanced Edition, a device which happily turns itself off whenever any one of its eight switches are flicked to the on position. The little guy just never gives up:
It’s terribly efficient. It’s terribly useless. It’s terribly adorable.
I almost wish I could get my hands on it so I could try to trick it somehow. Who knows; maybe I would just feel bad for it and give it a break.
This little device was built when its owner, forn4x, had a little printer problem. His Canon 850i managed to break its print head, but all the other electronics and mechanics were still salvageable. Since the printer wasn’t worth fixing, forn4x decided to put the DC motor and its optical sensor, which were used to move the print head, to work.
The control unit consists of:
- H-bridge for the motor (I actually used BD137+BD138).
- LCD (to be able to set the switch positions).
- PWM outputs for the servos (the one for the lid is still there).
- inputs for the encoder, inputs for the switches, internal pullups.
- 7805 voltage regulator.
You’d think all that material could go towards something more useful, and it definitely can, but would it be as entertaining? You can download the code and schematics for yourself from here to get a better look at how it works.
As its name implies, the little machine is actually the successor to the original “most useless machine.” The video for that one is here:
Image credit: Flavio Takemoto