Tacho Disc

thingiverse

I use a cheap DC motor like this:http://www.ebay.com/itm/smart-Car-Robot-Plastic-Tire-Wheel-with-DC-3-6v-Gear-Motor-for-arduino-/400985432465?hash=item5d5c982191:g:WVMAAOSwaNBUh7Xc I've used it with a tacho counter like this:http://www.ebay.com/itm/Slot-type-Optocoupler-Tacho-generator-Counter-Module-for-Arduino-Raspberry-pi-/281570892992?hash=item418eeedcc0:g:d8gAAOSwk5FUv1Kv Before finding the perfect fit, I ran a few test prints. I've uploaded an STL file that should fit perfectly in theory. However, to get it right, I had to print with about 0.1mm oversize. For those who may need something different, I've also posted the FreeCad file. On April 4th, my friend discovered his motor's shaft was closer to the gearbox edge than mine. To accommodate this difference, I created an updated version (version small) that fits with other type motors. The tacho for this model is about 4 mm smaller.