Made for an Arts seminar I attended for my General Studies, i.e. classes not organized by the faculty for CompSci: “Interaktive Exponate entwickeln mit dem RaspberryPi” (translation: Development of interactive exhibitions with the RaspberryPi).

Music: Rise by Meydän: CC-BY http://freemusicarchive.org/music/Mey…

I embedded some neodymium magnets in a ping-pong ball that I’d cut open. The magnets and weights (2 times 20 Euro cents) are held in place by use of a custom 3D-printed mount. Everything is glued in with hot glue, I sealed the ping-pong ball with silicone sealant and painted it with acrylic paint. (Be careful to take the eyeball out of the jar during transport or the paint might come off! I learned this the hard way.)

Below the jar are the same amount of magnets, which are rotated by a servo connected to a RaspberryPi Zero W. I used two servos since my original plan was to also have the eye rotate up and down. That didn’t really work out, unfortunately.

For motion detection with Python and OpenCV I found this tutorial to be very helpful: https://www.pyimagesearch.com/2015/06…

I also tried face detection, but the Pi Zero W turned out to not be fast enough for the task. Fortunately, motion detection appears to be sufficient for making the eye follow people around the room.

Video edited with Blender 2.8

[via Reddit – there are a few more insightful comments on that thread]

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