Hacked Gadgets Forum

December 24, 2011

Tiny Bipolar Stepper Motor Control

at 3:36 pm. Filed under Electronic Hacks


Check out the super macro video of this Tiny Bi-Polar Stepper Motor being controlled with an Arduino. This great part was scavenged from a blu-ray player.  This cute little motor has only 20 steps per revolution which is much less than the number of steps you would find in the large style steppers. I can normally think of a bunch of project ideas from every bit of electronics I see but this is something that I am just not sure how I could use it. I am thinking it would not have enough power to move anything substantial. I guess it would be used to move a tiny mirror to deflect a laser beam and display the time in the form of a line on the wall or something… What would you build with it?

Thanks for sending it in Dmitriy!

“So, here is what I’ve found out about the nano-sized stepper and the linear stage assembly:

  • It’s a 20 steps per revolution bipolar stepper.
  • The windings are 27.1Ω
  • The windings are most likely energized from the 1.8V source in the Bluray drive. I’ve used Arduino’s 3.3V output for the load supply of A3967 to simplify the setup. The motor gets slightly warm after a few minutes but the load current can also be adjusted on EasyDriver board to alleviate that
  • The linear stage has 2.5mm travel and it gets there in 14 full rotations. So, in theory, you can position this lens (or whatever else you choose to mount on it instead) with pretty darn good precision:
    it’s 0.179 mm lead step (thread step) and A3967 can take 160 steps (winding energizing steps) to complete one rotation, so, it’s a whopping 0.00111 mm or, in other words, 1.1 micron per step. This is millimeters, by the way, not to confuse with thousands of an inch. Sounds like it could be used for positioning of samples under a microscope by someone who does not want to shell out $500 for a professional positioning stage. Just a thought …
  • The end position sensor has three wires coming out of it and is most likely an LED/photodiode pair – I’ve yet to do more research on that. but it’s nothing short of amazing how they managed to put it in the assembly!”