Team BumbleB 3339 is proud to present our 14th robot - “Archer”:
Come watch us at ISR 1 and ISR 3!
P.S
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Limelight turret!
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Finally, another team making use of LimeDAR!
Hey,
Love the camera turret. Would love to know more about its implementation, both mechanically and on the software side
Cheers,
Sure,
Mechanically, we used a slip ring for allowing the turret to rotate continuously without any limitations, so we don’t have to worry about tearing the cable.
This is one of our prototypes for the turret on the robot.
For tracking tags with the turret, we look for all the tags that are visible from the limelight’s angle and then choosing the best tag that will give us the most accurate results, we do that with the distance and angle from the tag.
And for knowing our position on the field, we are calculating the Limelight’s position on the field with Limelight’s software, then we just calculate the robot’s position with the Limelight’s position relative to the robot.
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Thanks so much for the response.
Where is the motor located in this setup?
The motor we used is a BAG motor, and it is mounted below and with a little bit of offset from the turret (for adding reduction gear and leaving space for the slip ring).
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Interesting!
Thanks again for the response
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Did you guys run the ethernet cable through the slip-ring as well?
I believe that’s the only thing that needs to go through there so suppot a limelight.
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Depends on if you choose to do POE or not. I havnt seen what the slip ring looks like so I didn’t know how to run ethernet up to the limelight
From their robot reveal you can see they are powering the LL through POE, which seems easier since it requires less cables running through the slip ring.
But even if they were not powering though POE, to achive full rotation without limits, they’d have to run the ethernet cable through the slip ring (or else there won’t be a reason to use a slip ring).
I’m not sure what is exactly the connection from the slip ring to the cable though. Could be soldering or something like that.
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Oh ok gotcha, thank you. I assumed it was but I didn’t know how they connected it. Whether they stripped the ethernet cable or something else.
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Yeah, I’m not sure as well, would love to hear what they did exactly
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The slip ring itself comes with “pre installed” cabels that are already connceted to its base, so you get a plenty of cable from both sides of it to use.
We do used POE as you said, to reduce the amount of cables running through the slip ring. If I’m not wrong, this specific slip ring offers up to 12 different cables you run through it.
Of course, once you have the cables connceted to the slip ring, you can join them to create whatever type of connector you want. It this case, an Ethernet connection.
The cables attached to the slip ring are long enough to reach the LL, so we only needed to find a way to reach the AP.
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Because the base of the turret is a 3d printed gear that seats on top of a slip ring, it was quite wobbling. So we added a gear on the other side of the turret for trying to make the it more stable by adding some friction to it.
Turns out it works and the turret stopped wobbling.
p.s, the final version of the turret was strong enough and didn’t wobble so much (if at all). The gear is only in the CAD and not on the actual robot (although we left a place for it just in case).
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Big fan of this robot.
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