Introduction: Useless Box V1

A useless box is a device which has a function but no direct purpose. It may be intended to make a philosophical point, as an amusing engineering "hack", or as an intellectual joke. Devices which have no function or which malfunction are not considered to be "useless box".

The most well-known "useless box" are those inspired by Marvin Minsky's design, in which the device's sole function is to switch itself off by operating its own "off" switch. More elaborate devices and novelty toys, having some obvious function or entertainment value, have been based on these simple "useless box".


Today I am going to share how to make one

Step 1: What Do We Need ?


  • DC geared motor
  • Battery holder
  • DPDT switch
  • SPDT snap action switch
  • MDF plywood or wooden box
  • Wires
  • Soldering iron
  • PVA glue or fevicol
  • Hex saw
  • Drilling machine

Step 2: Working Principle

Step 1: We toggle the DPDT switch which make the motor move in clock wise

Step 2: The Arm toggles the switch, motor direction is changed to anti clock

Step 3: The arm hits the SDPT switch to break the circuit, which in-turns stops the arm from moving

Step 3: The Box

  • You could buy a box or make one
  • I decided to make a new one using 4mm mdf sheets
  • The box I made is 105 mm x 100 mm x 160mm
  • Cut the six side ( except the top cover ) and glue them together using pva glue or fevicol
  • I used masking tape to hold the box together
  • Leave it to dry for 4 hrours
  • Add first half of the top cover and glue it in place
  • Second half must be connected via a hinge.
  • Since I did not have a suitable hinge, I used making tape to work like a hinge

Step 4: The Arm Assemble

  • The Arm is cut in a "7" shape ( 55mm x 70mm) and fix toa dc geared motor
  • Based on the box height, find out the height the motor needs to be, so that the arm could toggle the switch
  • Mine was 43mm
  • Fix the motor on the wooden block using cable ties

Step 5: Circuit

  • Make connections as per the circuit diagram
  • Place the SPDT snap action switch just below the arm, as shown to break the circuit when needed
  • I used tooth picks to hold the SPDT switch in position
  • Test the circuit before we fix everything

Step 6: Finishing

  • Before fixing the DPDT switch, place the motor with arm assembly in the box
  • Get the right position to place the switch and the arm assembly
  • Once you have that, super glue or nail the arm assembly
  • Fix the the switch
  • Connect the batteries
  • Play On !!

Watch the video to see how it works

Please share your comments and suggestions