Has Anyone ever made a DIY SlipRing

rwgast_logicdesign

I need to get some wiring to travel in to a cylinder that rotates 360degrees, and I was looking at premade solutions, they all seem kind of pricey, maybe not, im not sure what actually goes in to one of these.

Imagine you had a square platform with batteries and circuit boards on it, then you had something the shape of a pringles can mounted to the square platform that rotated 360 degrees using a stepper motor. On this cylinder you had ping sensors or leds or something like that mounted to the walls, now you need to run the connections for those components to the bottom of the cylinder, and out to the stationary square platform holding all the power and brains.

Anyone have a homemade way to get this done? Or something cheaper than 20 bucks for only a few wires. Im having a hard time even imagining how this would work without breaking the wires and connecting them to 2 pcb's with a ring for each wire, that could spin freely. Im pretty sure that made no sense but no matter im hoping there is a much simpler way to get this done.

Franklin

https://www.adafruit.com/products/736 or if you only need a couple of wires use a phono/soundcard jack.

Beau Schwabe

What you want can be done with a Rotary_transformer...
http://en.wikipedia.org/wiki/Rotary_transformer

The above link is more of a reference, but they can be scaled to provide larger amounts of power. Even with data communication.

Phil Pilgrim (PhiPi)

If you can use batteries to power the system, put everything in the Pringles can, including the servo. The servo shaft couples to the square base. Et voila! No slipring needed!

-Phil

rwgast_logicdesign

@Phil, the above was only an example, I had thought about that before but it can be done if the square base has motors attached to it. The plan is to put a wooden base on a Roomba chassis. Then mount trash can/planter or something like that on top of the base. The trash can needs to rotate kind of like an r2/d2 to interact with the environment.

@Franklin, adafruit slip rings were the original products I was looking at but there fairly exspensive, a headphone jack is a good idea if only a couple wires were needed! Alas Ill probably be running 20 wires or more between the rotating cylinder and the motor platform

@Beaua, id never seen these looks like a much better idea than a slip ring, the article says these are commonly used in VCR's I wonder if I could just pull one out of a VCR and reuse it, do you have any suggestions for a premade rotary transformer? I would need to pass a lot of 5/3,3v data lines and a power line up to 18v

Beau Schwabe

The VCR head was just an example, for your application you would need to scale that up. Data transmission can be done over the power so you don't need multiple rings as depicted in the VCR... essentially just two coils; one stationary, and the other rotating, but in close proximity to one another. What needs to be established first is what kind of current demands you need. There are efficient (resonant) circuits that can easily drive the primary coil. Gating the driver would allow data transmission. On the receiving coil, the primary, you treat it as an ordinary transformer ... bridge rectifier, capacitor filter, voltage regulator... monitoring the transmitted data would be just looking at the RAW output of the primary, before the bridge rectifier and looking for a make/break presence in the transmitted power. Sending data the other direction can be done by modulating the load. A transistor with a current limiting resistor across the bridge rectifiers DC output would do it. The primary sees this as a current surge, and in the case of a resonant oscillator driving the primary coil, it would be seen as a frequency shift in oscillation.

ctwardell

Instead of wires for individual sensors how about a uC on the rotating platform that interfaces the sensors and communicates with you main controller via I2C, SPI, UART, etc. so you have far fewer signal lines.

C.W.

erco

Adapt & overcome. http://www.ebay.com/itm/US-Type-Female-Male-RJ11-Swivel-Telephone-Adapter-Converter-/230880477233

garyg

I've been trying to implement some type of rotary connection to my 3 wheel configuration of a platform for a while now.
So far the RJ11 Swivel telephone adapter suggested by Erco, is the best one I've seen so far.
Building a swivel connector with slip rings gets complicated in that the alignment with bearings and brushes of some type is
difficult to achieve.
I've had some success at winding a ribbon cable inside of a container and connecting the outlet end to the swivel.
This causes trouble, because you need to limit the rotation to however many wraps are wound inside of the container.
Sometimes the ribbon cable kinks and ruins the rotation.
The rotation also needs some type of mechanical stop, if slip rings are not used.
I'm thinking that the moral of the story is:
Try something like the RJ11 Swivel to see if the electrical noise made by the slip rings works in your application.
That's just my 2Cents worth.

Phil Pilgrim (PhiPi)

If all the slipring handles is power, noise should not be an issue with proper filtering. For signals, you can always revert to optical coupling via an IRED and IR detector or RF wireless, if the coupling noise proves insurmountable.

-Phil

Duane C. Johnson

Stereo Phone Plug and Jacks.

Duane J

erco

Duane C. Johnson wrote: »

Stereo Phone Plug and Jacks

+1

vanmunch

I've bought a few on eBay for $10-12 that have 6 or 12 wires. They work great.

Ken Gracey

Here's one from Limor at Adafruit: http://www.adafruit.com/products/736

Now you can make a spinning Linda Blair head.

rwgast_logicdesign

Acually I think Erco's solution is perfect! Ive never seen those, but considering I have a thousand feet of cat 5 I routinely use for projects this is a no brainier 8 connections for < $4

EDIT:
Oops that for rj11 phone connectors, still a good solution, and im sure they make the same type of deal for rj45/cat5

felixmtt

Franklin wrote: »

https://www.adafruit.com/products/736 or if you only need a couple of wires use a phono/soundcard jack.

Adafruit is a good option to find the wires. You can also see few Slipring suppliers who can give you the required stuff.

SRLM

felixmtt wrote: »

Adafruit is a good option to find the wires. You can also see few Slipring suppliers who can give you the required stuff.

Hmmm. I'm not sure if this qualifies as useful or not (spam). It is tangentially related to the topic, but it's a link to bio's of companies that supply slip rings to the military. It seems like a link farm attempt to me.

Why does it seem like spam?
1. It's "felixmtt"'s first post
2. The lack of connection between the two sentences is a poor transition to his topic (and don't make sense together).
3. The link is not useful to this thread.

ajward

You can find them on eBay under $10:
http://www.ebay.com/itm/250Rpm-12-5mm-6-Wires-6-Conductors-Capsule-Slip-Ring-220V-AC-F-Monitor-Robotic-/290696966126?pt=LH_DefaultDomain_2&hash=item43aee3afee

I bought one a while back for about $8, but I don't see them that cheap right now.

@

frank freedman

This uses sliprings. http://www.youtube.com/watch?v=a1i8KFEtnok Wrapping around cables went out on these things in the early 90's. If you are careful, you could probably make your own slipping setup. The key is multiple brushes on each ring to assure continuous contact with the ring. These devices use +/- 350VDC, 115VAC, canbus and xray enable on the rings and gigabit data image data transfers over multiple wireless channels. That last would be pricey, but the rest you may be able to do. I have seen three or more brushes per ring, have not seen fewer.

Zoot

Here's my DIY slipring. You can't see it in this photo, but there are two "whiskers" on *each* ring so contact is always made. The rings are copper sheet wrapped around the dowel, glued and soldered.

Ttailspin

This is my first (and only) attempt at SlipRing tech...
Roombas Revenge


-Tommy