Help with Stepper Motor and Slip Ring

Hi All,

   I need to figure out how to get power and control signals from a stationary computer / PIC into a series of subsequent rings via rotating joints.

Ultimately, what I want to build is a form of motorized gyroscope that can transmit power and control signals to the inner ring motors.

- I'm using a Raspberry Pi 2 to control three Stepper Motors.
- The motors are getting power from an old AC/DC wall adapter.
- I currently have 3x NEMA 17 stepper motors
    - Yaw Motor/Axis
    - Pitch Motor/Axis
    - Roll Motor/Axis
- I've got 2x 12mm 12 8-wire slip rings that I hope can be used to send the control signals from the Controller to each motor.

The problem is that I'm not entirely sure how to connect those components together, let alone how to connect them to bearings to minimize tension on the motor shafts.

(I'm a software engineer, not an EE or ME.)

An example of what I want to build is this: 
( However I don't need anything in the middle, I just need a way to control the rotation of each ring layer independently by the stepped motors )

If anyone can point me in the right direction it would be much appreciated,
Mike C.

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caitlinsdad2 years ago

Look at adafruit.com for several different slip rings, https://www.adafruit.com/search?q=slip+ring&b=1

They have a mounting flange. I guess you can search for robot or 3D printer parts for shafts and such to mount things, Threaded rod, nuts, bolts, brackets and washers and lazy susan mechanisms can all make some kind of pivoting joint. Good luck.

MichaelC87 (author)  caitlinsdad2 years ago

I've already got two of the slip rings and a Raspberry Pi control board for the stepper motors. (https://www.adafruit.com/products/1196)

I need to figure out how to mount them to the bearings so that the slip ring and the motor shaft do not have all support the weight of the inner component.

In other words: What kind of bearings should I buy and how do I install them?

I think you are essentially looking for the same method to attach a wheel axle of a car. The shaft goes into a bearing that is attached to the frame. The engine is connected through a transmission or gearset for your stepper motor. If you are doing direct drive, the shaft of the stepper motor needs to be coupled to the shaft of the inner pivoting "sphere" or gimbal. Find an old set of rollerblades or push scooter at the thrift store. Take the wheels off and screw the entire rubber wheels to your frames. You should still be able to insert threaded rod to use as your gimbal shaft into the wheel bearing. The rest is trying to get parts made or hacked so that your motor can turn it.

MichaelC87 (author)  caitlinsdad2 years ago


I'll give that a try.

oh, look at instructables with raspberry pi to control stepper motors, adafruit should also have a few tutorials on their learning system.