Location on Direct Drive

[Chas_G]

We are direct driving our mechanism this year, and we do not have the opportunity to put an encoder on the axle on the opposite side of motor.

Our initial idea was to wrap a nylon rack gear around the plate attached to the motor, but the nylon is not nearly pliable enough.

Any ideas to get a location on this axle?

Thanks for your consideration!

[RyanCahoon]

Put a sprocket on the axle and implement your own encoder using a photointerrupter or geartooth sensor (if using a ferrous sprocket) or make a reflective encoder by printing a codewheel pattern and gluing it to your mechanism and using a reflectance sensor.

http://www.bushytails.net/~randyg/encoder/encoderwheel.html

--Ryan

[apalrd]

Use some small plastic 25-pitch sprockets to attach a potentiometer or encoder (depending on the range of the device, if it is continuous an encoder, if it has a limited range, a potentiometer).

Why plastic sprockets? A sensor has almost no load, and plastic is lighter than steel or aluminum.