October 2017 – How to sort marbles.

The problem this month is to sort various colored marbles.  I was looking for classification methods as well as mechanical methods for handling marbles.


  • Shine R, G, B light from LED on marble and measure reflected light using a photo resistor (or photo diode or transistor).
  • OpenCV on Raspberry Pi w/ camera
  • Measure capacitance difference (is there any?)
  • Head absorption difference (perhaps flash the marble with xenon strobe light)
  • Diameter difference (order different colors from different manufacturers).
  • other offbeat methods like drone with camera, waiting for evolution to do something.

Mechanical Separation

  • Solenoid to push one color off track
  • Puff of air to push one color off the track
  • Servo w/ arm to push marble in one (or two) directions


Triangle Embedded Interest Group