Quote:
Originally Posted by Al Skierkiewicz
Steve,
You asked an engineering question, so I gave you an answer. I didn't say it was a good one. There is no possible way to not have some noise in a slip ring, particularly one that is carrying a lot of current. However, with large brushes or multiple brushes, you should be able to transfer enough current to be useful. Slip rings for sensor use should be fine since the current is fairly low, and the noise should also be low. Please be sure that power supply for sensors are filtered near the sensor.
There are some mercury filled rotary electric connections out there. I am against using them but I do believe the GDC answered (In a Q&A) that they could be used this year. In the hard hits, and misalignments I see on robots during inspection, I believe the chance for a mercury spill is pretty high. For that reason, I advise against their use.
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Regarding mercury-filled electrical connectors, my team has some sitting on our shelf (in 2006 we toyed with the idea of a continuously rotating turret). We didn't end up using them in competition, but you should read the product documentation CAREFULLY if you want to. Currently, no Mercotac electrical contact (Mercotac was the only manufacturer of these as of a couple years ago) is rated for more than 30A of continuous current. This all but rules out these devices for a high-traction swerve drive.
One other warning: slip rings (especially home made ones) always add a bit of noise to a signal. Be careful when using analog sensors with slip rings! (I know from experience!)