A Dutch inventor has created a machine that automatically sorts M&Ms and Skittles by color. It cost around $500 to make, though Willem Pennings says it was well worth that for the learning experience.
The machine is based on an Arduino controller, with various 3D printed parts and, most importantly, an RGB sensor.
It sorts at a rate of two pieces a second, meaning a standard sized bag takes around two to three minutes to sort. The basic mechanism and controls could be easily adjusted to work with other colored objects as long as they are all roughly the same size and shape, and that the shape is regular.
Pennings goes into intricate detail on his website about how he constructed the machine. He notes that while the basic mechanics are straightforward, one of the main engineering problems was avoiding the distribution tubes becoming clogged with candy, something he solved by making sure the unsorted candy is constantly mixed.
The machine includes variable color LED strips which light the appropriate color both to show the sorting process is working and as a novelty to show what color the most recently sorted piece was. Pennings says the machine had to be constructed in a particular fashion to avoid these lights being seen by the RGB sensor and causing a feedback loop that led to mistaken sorting.
Trivial as the machine might seem to anyone who isn’t disproportionately pleased by such neatness, it might have a practical purpose. Van Halen infamously had a “no brown M&Ms” clause in their venue rider which is often cited as an example of rock star pettiness. In fact it was deliberately placed there to test whether the venue had read the rider in full and was thus paying suitable attention to the safety requirements of the band’s staging and electrical requirements.