Motorized Fridge Magnet Gears

thingiverse

WARNING - This project uses magnets, which may be hazardous if ingested by children. Keep magnets out of reach of kids. https://www.youtube.com/watch?v=Pxnov2F6h2o I began with Fridge Magnet Gears by hypamat and made the following enhancements: 1) I altered the largest gear to create a double-bearing crank gear, one bearing for the gear itself and another bearing so the handle turns extremely smooth. 2) I added several additional gears - some swirly/spiral ones, a heart gear, a star gear, etc. 3) I added triple-magnet base because the single-magnet base did not stick well to my whiteboard. 4) I added motorized gear with built-in magnetic clutch. It uses NEMA 17 short body stepper from Amazon, DRV8834 driver from pololu, and ATTINY85 CPU. I chose a 3.3V stepper, and the entire circuit is easily powered by a USB battery pack. The motorized gear is entirely optional; the project functions very well with the hand crank alone. Magnets used are 10mm x 3mm, commonly available on Amazon. Bearings used are 608 hybrid ceramic skate board bearings from eBay. Updates: 5/30/2019 - I added dragonfly gear. Updates: 6/23/2019 - I added planetary gearset (see https://www.thingiverse.com/thing:3709819 for more details). The ring gear was remixed to make it compatible with the other fridge magnet gears, and the planetary carrier was remixed to include magnet pockets. You'll need an M2.5 machine screw, M2.5 threadsert, and several more 608 bearings to assemble this gear.