N20 Motor Quick Test Stand

thingiverse

This is a stand for testing the common N20 gearmotors found on eBay & AliExpress. They come in multiple gear ratios and it's quite easy to get them mixed up. This stand gives you a quick way to go through all your motors and measure them with a non-contact tachometer like this: https://www.amazon.com/Digital-Photo-Laser-Tachometer-Contact/dp/B001N4QY66/ You'll need: 2x M3x12mm socket cap hex screws 2x M3 nuts 2x alligator clips 9v battery (optional) The nuts go inside and the screws go in from the bottom. Then clip the alligator clips to the screw heads You'll need to take care to make sure the nuts are at even height. I got mine in by dropping the nuts in there and getting them lined up with the indentations for them and then holding them in place with an N20 motor while i tightened the screws up. The test wheel part is optional.The tachometer will measure off the flat of the motor shaft, but if you need to you can print the test wheel and stick the reflective tape sticker from your tachometer to that to measure. The 9v battery is optional. I use the 12v motors, so it's nice to just connect a 12v power supply to the clips instead, but it might also be nice to keep it portable so more options are better than less.