When you think of a “7-segment” display, your mind naturally goes to something involving LCD or LED technology. As seen here, however, this 0-9 pattern can also be duplicated mechanically using a series of electromagnets.
Neeraj Rane’s 3D-printed device is controlled by an Arduino Nano, along with a shift register. These activate seven hand-wound coils that push the magnet-embedded segments in and out, via a series of IRF540N MOSFETs.
As of now, the display simply cycles through numbers. If a few more digits were added, and perhaps a user interface and/or an RTC module, it could form the basis of an even more interesting project. Check it out in action below!