Thanks a lot for making the information necessary to build an optomotor apparatus available through your papers and web page. We bought all the products as specified in the list of parts table, and in most cases, we managed to get the exact same parts that you recommend. We are now trying to assemble the optomotor apparatus but we run into a problem with the motor. Instead of turning smoothly (as in your video), all our motor does is turn back and forth. We checked the connections and even changed the stepper motor and drive, but the problem persists. Please help!
It sounds like the motor isn’t connected properly. Different motors have different wiring and colour coding… it’s quite frustrating.
Double check the specs of your motor and the output of the driver board. There are two coils in a bipolar motor and these need to be correctly wired up.
With a multi-meter you can also check both coils work (test the resistance of each coil).