This Minimalist Masterpiece Mesmerizes Minute After Minute by Magically Moving Magnetic Spheres
Troy Hawkins' wall-mounted timepiece uses ball bearing as hands.
You’re probably familiar with the trick where you put a magnet under than table to move an object on top. Creator Troy Hawkins (AKA “tomatoskins') has taken this concept and gone several steps further to convert it into an excellent clock. This device, which is inspired by the STORY levitating timepiece, uses two ball bearings that act as hour and minute hands. There are no marketings on the face of this externally minimal design, just a walnut veneer and many coats of lacquer to keep it “un-grooved” for as long as possible.
Inside, a 3D-printed ring gear setup moves the magnets that hold each bearing in a clock pattern, rotated by a pair of 28BYJ-48 steppers with corresponding ULN2003 driver boards. An Arduino Nano is used for control, along with an RTC module to keep it accurate. Hall effect sensors are also implemented on both the hour and minute hand mechanisms.
The project involves a variety of woodworking and 3D printing techniques, including gluing the ring gear together with an acetone solution so it can be printed in multiple pieces. It looks like a fantastic build, and according to Hawkins “turned out better than [he] had anticipated.” Arduino code, plus STL files, are available in his write-up, and the SolidWorks models are even available if you want to make modifications.