Slip Ring with Flange mounting to stepper motor

For other supported Arduino products from Adafruit: Shields, accessories, etc.

Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.
tomega3
 
Posts: 29
Joined: Sun Aug 05, 2012 11:24 am

Slip Ring with Flange mounting to stepper motor

Post by tomega3 »

Hi, I would like to mount an ultrasonic sensor to a stepper motor and should probably use a slip ring like the one with the flange on your website. I am good with electronics and programming but have very little mechanical knowledge.
Can some one help or suggest a method to attach the slip ring to a stepper motors shaft and then via the slip ring to a platform that I can mount the sensor to?

Thanks

User avatar
adafruit_support_mike
 
Posts: 67446
Joined: Thu Feb 11, 2010 2:51 pm

Re: Slip Ring with Flange mounting to stepper motor

Post by adafruit_support_mike »

To connect a slip ring to a motor shaft, you need a toroidal ring: one with a hole down the center. Those tend to be larger and more expensive.

The ones we have are designed for offset drive: the bearings in the ring serve as the main pivot for the rotation, and the power which provides the rotataion comes in from the side. You provide rotational drive with a pulley and belt or a gear and pinion arrangement.

If your design permits it, you can also mount the motor and slip ring at opposite ends of a shaft. The motor provides power and a bearing at one end, the slip ring provides a bearing at the other end.

tomega3
 
Posts: 29
Joined: Sun Aug 05, 2012 11:24 am

Re: Slip Ring with Flange mounting to stepper motor

Post by tomega3 »

Thanks for the info,
A picture or two would really help showing both techniques.
Maybe a tutorial could be done.

User avatar
adafruit_support_mike
 
Posts: 67446
Joined: Thu Feb 11, 2010 2:51 pm

Re: Slip Ring with Flange mounting to stepper motor

Post by adafruit_support_mike »

Using the slip ring as a pivot and driving from the side would look like this:
side-drive.jpg
side-drive.jpg (27.51 KiB) Viewed 3453 times
Putting the motor and slip ring at opposite ends of a shaft would look like this:
yoke.jpg
yoke.jpg (15.74 KiB) Viewed 3453 times

tomega3
 
Posts: 29
Joined: Sun Aug 05, 2012 11:24 am

Re: Slip Ring with Flange mounting to stepper motor

Post by tomega3 »

Thanks for the pictures, it now makes sense.
My next steps are to find and purchase the pulleys and belt or gears.
My goal is to make a continuous 360 sweep setup for ir and ultrasonic sensors.
Any recommendations on where to find the parts would be greatly appreciated.

User avatar
adafruit_support_bill
 
Posts: 88090
Joined: Sat Feb 07, 2009 10:11 am

Re: Slip Ring with Flange mounting to stepper motor

Post by adafruit_support_bill »

We have several sizes of toothed pulleys & belt in the shop. McMaster Carr is also a good resource for all things mechanical.

SimpleMe
 
Posts: 3
Joined: Wed Mar 26, 2014 11:01 am

Re: Slip Ring with Flange mounting to stepper motor

Post by SimpleMe »

I purchased the 12 circuit slip ring, which works great for everything I run through it except the two video data lines from a CCD camera. Does anyone have an idea how to solve this problem?

User avatar
adafruit_support_mike
 
Posts: 67446
Joined: Thu Feb 11, 2010 2:51 pm

Re: Slip Ring with Flange mounting to stepper motor

Post by adafruit_support_mike »

What happens to the video signals?

SimpleMe
 
Posts: 3
Joined: Wed Mar 26, 2014 11:01 am

Re: Slip Ring with Flange mounting to stepper motor

Post by SimpleMe »

Sorry for the late response, The signals normally run through a USB cable to the computer. Basically I just cut the cable in the middle and attached the wires from the camera to one side of the slip ring and the usb cable end I cut off was connected to the other side of the slip ring (side which does not spin) power and ground, no problem, but as soon as I move one of the data wires to the slip ring, video goes blank. I have tried restarting the software for the camera and even rebooted my computer- still no video.

Thanks

User avatar
adafruit_support_mike
 
Posts: 67446
Joined: Thu Feb 11, 2010 2:51 pm

Re: Slip Ring with Flange mounting to stepper motor

Post by adafruit_support_mike »

That could be any number of things..

Slip rings can be noisy because of the sliding contact between the fixed and moving sides. The ones we sell aren't specifically rated for video or other high-speed signals, so it's hard to say how much noise they'd add. You might also be seeing problems from capacitive or inductive coupling in the video lines. High speed signals need to be handled carefully, which is why we use coaxial cable from antenna to receiver.

If you have access to an oscilloscope, test a straight DC connection to see how much noise you get, and if the 'scope knows how to read NTSC signals (fairly common) see what you get as difference between the input and output sides.

SimpleMe
 
Posts: 3
Joined: Wed Mar 26, 2014 11:01 am

Re: Slip Ring with Flange mounting to stepper motor

Post by SimpleMe »

Thanks, I'll give the O-Scope a try, last night I took the data lines and made a twisted pair out of each (wrapping the signal with a ground wire on both sides of the slip ring, I'll test it tonight.

User avatar
protezoid
 
Posts: 3
Joined: Wed Oct 22, 2014 10:12 pm

Re: Slip Ring with Flange mounting to stepper motor

Post by protezoid »

My stepper motor is placed on a very low speed rotating structure that would turn between 30 and 180 rpm so i need a low noise slip ring. Can your slip rings be used to transmit stepper motor pulsed signals at 200 rpm without creating spikes noise that could cause precision/performance problems? The data sheet says electric noise is smaller than 0.01Ω and the motor's phase coil are 0.9Ω, so i guess it should be ok.

The mechanical durability of those slip ring is not mentioned and this could become a problem as the noise increases over time, can you get this information from your supplier? This is an important detail and i would program this info for maintenance before the spikes makes the stepper erratic.

Can this noise be corrected electronically with a filter?

Thanks

User avatar
adafruit_support_mike
 
Posts: 67446
Joined: Thu Feb 11, 2010 2:51 pm

Re: Slip Ring with Flange mounting to stepper motor

Post by adafruit_support_mike »

Our slip rings can handle rotational speeds up to 300rpm, which should be adequate for what you're doing.

The amount and kind of noise a slip ring generates depends heavily on the kind of mechanical system you connect it to, the speed of rotation, etc. There are no simple answers on that score.

Filtering can reduce noise, but it will also remove any signals operating in the same frequency range. What kind of signals do you plan to send through the slip ring?

User avatar
adafruit_support_mike
 
Posts: 67446
Joined: Thu Feb 11, 2010 2:51 pm

Re: Slip Ring with Flange mounting to stepper motor

Post by adafruit_support_mike »

Our slip rings can handle rotational speeds up to 300rpm, which should be adequate for what you're doing.

The amount and kind of noise a slip ring generates depends heavily on the kind of mechanical system you connect it to, the speed of rotation, etc. There are no simple answers on that score.

Filtering can reduce noise, but it will also remove any signals operating in the same frequency range. What kind of signals do you plan to send through the slip ring?

User avatar
protezoid
 
Posts: 3
Joined: Wed Oct 22, 2014 10:12 pm

Re: Slip Ring with Flange mounting to stepper motor

Post by protezoid »

Thank you for the reply, i'm building a rotocast machine. Here is an example video. My machine will be smaller:
http://www.youtube.com/watch?v=ofzg_Hjukzg

Basically, it's a structure rotating in the Y axis and within is another structure rotating in the X axis. This machine will be able to rotate a hollow silicone mold in which a liquid plastic polymer is poured and cure solid while it is spread evenly onto the inner surface of the mold, while the rotocast machine rotates. This is useful to make automatic hollow plastic replicas.

In the example video, the main structure is turned by a single powerful motor and the mold is turned by a chain pulley. My machine will have two motors; one step motor will rotate the main structure and another one on this moving structure will rotate the silicone mold, so it will need a slip ring connected to the main structure axis to transmit 4 digital signal of 2 A. The rotation is slow, something like 60 to 180 rpm. The motors are both 1,8 degrees that need 200 pulses to make a full rotations so the maximum signal should be no more than 600 hz. Maybe a low pass filter could reduce the spikes? I'm just concerned about the effect that the noise could have on the torque performance if the noise should increase overtime, but this depends on the lifetime of this slip ring. Step motors are sensible devices and noise could create resonance problems. Are there specs on the noise aspect and the lifetime limit of the slip rings in relation to rpm?

Thanks André

Locked
Please be positive and constructive with your questions and comments.

Return to “Other Arduino products from Adafruit”