The detail that caught me off guard is that the gears were not printed on a filament machine at all. Yeah Nah DIY had the nylon gears selectively laser sintered, which stands out in a build where everything else is clearly home workshop territory. The project itself is a smart replacement for a desk's manual switch, built around an Arduino Nano, a rotary encoder, a relay module, a micro switch and a DC-DC converter that steps the 28V to 30V supply down to 5V.
The assembly path is worth reading closely. The stock control module and its PCB were inspected first, then the original switches were swapped for two relays wired to normally open and normally closed terminals. A rotary encoder board sits on a bracket and drives through printed gears, and the firmware leans on a rotary encoder library to work out the desk height. The wedge-shaped casing was drawn in CAD, printed on a textured PEI plate, and features miniature lever microswitches plus threaded brass inserts. The electronics went through several prototype perfboards before the final board was seated in the enclosure.
The gears tell the best story. The first versions were printed in PLA and turned out too loud, so nylon became the replacement, but the nylon ones initially slipped on the drive rod. The fix was mechanical: a hole drilled through the gear collar and an M3 screw installed as a locking bolt. After that, the gears turn in sync with the desk shaft and the desk hits tested heights of 700 mm, 800 mm and 1000 mm accurately, with calibration done at the 700 mm minimum. Both the physical panel, with its five circular button faces, and the computer app slider move the desk smoothly.
The open question for me is noise and wear over time. Belt drive ideas have been floated as an alternative for accuracy and quieter running, so whether the geared approach holds up long term seems unresolved.
Project by Yeah Nah DIY. Watch it on their YouTube channel: