Lots of fun open source stuff, but I had a lot of fun working on a survey taking m&m dispenser. The goal was to encourage students to answer survey questions that would help the faculty get a better idea of what the students found most valuable (different things they wanted to learn, classes they found useless, etc.). So me and another student built this :) Its a node server running on an Intel Galileo, which served up an admin and survey interface using React. When a student answered a survey question, a servo would turn a gear, which interfaced with a rack and pinion that had two little pits in it. When it would slide under the jar, two m&ms would fill the pits, then the rack and pinion would push them out. Then we had a webcam hooked up to the end of it that would compare the colors of the m&ms to see if they were the same. If they were the same, the student would get more m&ms. The gear pieces were 3D printed.

We could never get the webcam stuff to work right with the Galileo because OpenCV (the computer vision library we were using to interact with the webcam) could not be built/compiled on such a specific version of Linux. Later, I was able to do it with a RaspberryPi, but never got it reintegrated.