Re: Lunacy Wheels Static Electricity
 

When driving the robot around at school, especially on carpet, you may want to hang a short length of chain from the chassis to drag on the floor. Don't use #35 roller chain, use something like you would use on a swingset :)

I don't know if this will be allowed at the competitions, but hope that it will be.

This will help prevent the chassis from building up a charge as the wheels spin on the carpet.

The use of drag chains is standard practice in industry on carts used to move static sensitive items, since the rubber wheels on a metal cart will do the same thing when it is being moved around.

Re: Lunacy Wheels Static Electricity
 

We were discussing this yesterday and some of our mentors think that if this become too big of a problem then FIRST will probably provide teams with a grounding strip at the regionals.

Re: Lunacy Wheels Static Electricity
 

That reminds me of the rule a few years ago where the robot had to be touching the field in a loading zone to pick up a game piece and everyone put wire ties on the center of the frame that touched the point of the triangular area.

I wonder, do they make conductive wire ties?

Re: Lunacy Wheels Static Electricity
 

Yeah, tonight we put a little pigtail wire on our robot because we ran out of people to "help" us move the robot that didn't know it would shock them (I know, I'm evil). Once we did that, you could barely hear a slight tick when you touch the frame, and you can't feel anything. A grounding brush eliminates most of the static electricity, but since there still is some, it's a potential worry. Static like this sits around a few thousand volts, and although it's very low current, it's enough to take out a single microchip. On our robot, everything is insulated from the frame except for the motors, which feed through the TB's. If you insulate the TB's, all of your electronics should be fine. However, I think the Jaguars' capacitors will take up the static if you happen to have something touching the frame. Just make sure more than ever that this year, YOUR FRAME IS NOT AT GROUND POTENTIAL. Last year, we had several wiring problems, and our frame was grounded, so every time someone got a little careless with a PWM cable and the +5 touched the frame, you got a pretty little fireworks show. This year, those pops could happen even without a short because of this static.

If they do not allow us to use grounding brushes (or even if they do, to lessen movement resistance), you might consider putting grounding brushes on the wheels themselves. It's the dielectrics that store charge (like the wheels and the floor), and the metal frame only conducts it. If you conduct it back into a closed circuit, it should eliminate the static electricity. I will test this tomorrow and report back its effectiveness. For right now, act as if this static electricity WILL damage your electronics and take the appropriate precautions. Just remember, nylon spacers are your friend!