Looking for slip rings and distributors

[sanelss]

Our team is attempting to do swerve drive this year and we are looking for some slip rings but having troubles finding appropriate ones. we need 2 40A lines for a cim and 3 signal lines.

What slip rings does your team use(if any) and where do you get them from?

[Mk.32]

Originally Posted by sanelss

Our team is attempting to do swerve drive this year and we are looking for some slip rings but having troubles finding appropriate ones. we need 2 40A lines for a cim and 3 signal lines.

What slip rings does your team use(if any) and where do you get them from?

I have used these on non-FRC related projects with great suceess: http://www.mercotac.com/html/430.html

[Chadfrom308]

Adafruit has 2 amp ones that you can run PWM cable through, that might be helpful if you can modify your design a little

[sanelss]

Originally Posted by Chadfrom308

Adafruit has 2 amp ones that you can run PWM cable through, that might be helpful if you can modify your design a little

for the servo no problem, but we still need 2 40 amp channels for the cim and if we are to use a secondary slip ring the cim slip rings needs to be a through hole style.

[sanelss]

the only unit they have that meets our needs is the model 830. Why do they not list prices???? I imagine they will be 100+ each but if they are too much more than that may be an issue.

[Mk.32]

Originally Posted by sanelss

the only unit they have that meets our needs is the model 830. Why do they not list prices???? I imagine they will be 100+ each but if they are too much more than that may be an issue.

As with most suppliers you have to contact them for a price:
http://www.mercotac.com/html/purchasing.html
Contact info at the bottom, they are local to me so I just drive over and pick stuff up.

These are expensive, have you thought about designing your swerve so it is independent like 1717/others?

[Peyton Yeung]

I believe Bomb Squid (Team 16) uses slip rings in their swerve. You might try contacting one of them.

[sanelss]

Originally Posted by Mk.32

As with most suppliers you have to contact them for a price:
http://www.mercotac.com/html/purchasing.html
Contact info at the bottom, they are local to me so I just drive over and pick stuff up.

These are expensive, have you thought about designing your swerve so it is independent like 1717/others?

independent? not sure what you mean here. can you elaborate?

[asid61]

Originally Posted by sanelss

independent? not sure what you mean here. can you elaborate?

Like, able to rotate freely without the cim. Essentially, outsource all wires to areas outside the rotating module.

[sanelss]

Originally Posted by asid61

Like, able to rotate freely without the cim. Essentially, outsource all wires to areas outside the rotating module.

well our design not only has a cim rotating with it but also a servo(we are doing a 2 speed shifting swerve, or at least attempting to) so we need some kind of slip ring with 5 channels 2 of which needs to be 40A for the cim. i mean we could just stick wires through the center as people have pointed out but we don't want to have to deal with all the issues related to untangling the wires.

[Aren Siekmeier]

Originally Posted by sanelss

well our design not only has a cim rotating with it but also a servo(we are doing a 2 speed shifting swerve, or at least attempting to) so we need some kind of slip ring with 5 channels 2 of which needs to be 40A for the cim. i mean we could just stick wires through the center as people have pointed out but we don't want to have to deal with all the issues related to untangling the wires.

You can also find through-bore slip rings that would allow you to combine multiple different slip rings with a wide variety of specs. For example these guys.

Some suppliers can also build custom slip rings for you, but you'd have to be careful about the legality of these during the season.

[sanelss]

Originally Posted by compwiztobe

You can also find through-bore slip rings that would allow you to combine multiple different slip rings with a wide variety of specs. For example these guys.

Some suppliers can also build custom slip rings for you, but you'd have to be careful about the legality of these during the season.

thanks. i've found a few potential suppliers but none of them have prices and who knows what kind of lead time is required. sourcing these $@#$@#$@#$@# things is no easy task =\

[Dunngeon]

Originally Posted by sanelss

well our design not only has a cim rotating with it but also a servo(we are doing a 2 speed shifting swerve, or at least attempting to) so we need some kind of slip ring with 5 channels 2 of which needs to be 40A for the cim. i mean we could just stick wires through the center as people have pointed out but we don't want to have to deal with all the issues related to untangling the wires.

If you look at Pwnage's CIM in wheel swerve ( I think), they have a piece of code that, depending on how far the swerve module has rotated (with three complete rotations in one direction being the max IIRC) automatically turns the wheel the opposite direction to compensate for rotation of the wires. It's a fairly simple fix, and they said it had a minimal impact on reaction speed of the robot.

This would remove the need for slip-rings, which would bring the overall cost of the modules down quite a lot while simplifying construction.

Also, if you don't mind me asking, exactly how are you planning on packaging this swerve module?

[sanelss]

Originally Posted by Dunngeon

If you look at Pwnage's CIM in wheel swerve ( I think), they have a piece of code that, depending on how far the swerve module has rotated (with three complete rotations in one direction being the max IIRC) automatically turns the wheel the opposite direction to compensate for rotation of the wires. It's a fairly simple fix, and they said it had a minimal impact on reaction speed of the robot.

This would remove the need for slip-rings, which would bring the overall cost of the modules down quite a lot while simplifying construction.

Also, if you don't mind me asking, exactly how are you planning on packaging this swerve module?

We've done a system like that before and we know it is doable we would just rather avoid it hence why we are trying this approach. it certainly is going to cost more but we want to try this during the off seasons to see if we can perfect it by competition time or go with another system(like the one you mentioned)

not sure what you mean in regards to packaging it, elaborate? As in the over all structure of it or???

[Al Skierkiewicz]

Everyone,
The Mercotac slip rings are not slip rings in the true sense of the word. They are mercury filled contacts and are not legal on FRC robots. If you read the application notes on these contacts, you will see warnings about mercury leakage when mechanically stressed or when max current is exceeded. I contacted the manufacturer and was told that those events are rare but do occur. Mercury spills on an FRC field will close down the event.