Saturday, June 22, 2013

Competition in Uselessness

It is believed that the idea of the Useless Machine was first formulated by Marvin Minsky and implemented by Claude Shannon more than half a century ago. Nowadays this concept is quite a popular one (1). The Useless machine in one sentence may be defined as automaton with only two possible states: 

  1. It is turned off. 
  2. It is turned on.

Transition from state 1 to state 2 happens as a result of external force, and the transition back from state 2 to state 1 is provided by the machine itself. If this machine is electrical (as Claude Shannon built it) energy for the transition is taken from the battery charge. For a purely mechanical machine it is either gravity or spring tension. In its classical implementation the electrical circuit looks like this:
I first got knowledge about that device from Make Magazine (2). Until the time of publication there were tons of videos on YouTube with various versions of this device. While browsing them I paid attention to the fact that most of the machines use a toggle switch as the machine control element. A rocker switch was never used. But it is absolutely clear that a rocker switch may provide the same effect. Why does nobody use it? Good opportunity to contribute something new to an old concept, right?

Using a rocker switch instead of toggle means that the force applied to the switch by the machine arm should go not in a horizontal direction (from side to side) but rather in a vertical direction (from top to bottom). While playing mentally with kinematics to make it workable one more thought came to my mind: why not eliminate the working arm? Let the box lid do the job. This way the machine will be truly different from other animals in the herd: rocker switch instead of toggle and no arm at all.

It took me some time and several attempts to create a two dimensional cardboard model like this:

As soon as my model proved the concept worked, the actual implementation with wood and wires was not so hard :

And here are some technical details:

  • Motor: Solarbotics GM2 gear motor
  • Rocker switch: Radioshack DPDT Switch ( 275-695 ),
  • Micro switch: Radioshack SPDT Switch with Roller Lever (275-017)
  • Wooden box and other wooden parts from the local Michael’s store.
Among the comments left on this YouTube video was a comment from the user xsolarwindx: “this is f*ing stupid”. For any other occasion such a comment would be insulting but for the useless machine maker that could be considered as highest degree award. I think everybody would agree, right?

Updated 10/27/2015.
I have published more detailed description of this project updated version here:


1. Here is the site of the company entirely dedicated to useless machines :

2.  Brett Coulthard. '"The most useless machine" (Issue 23 of Make Magazine). 2010