Van De Graff effect on shooter

[Not2B]

This is part question, part help...

Has anyone else experienced any EMC issues with their shooter wheels? We spent alot of time calibrating our shooter / camera combo today, and we were running the shooter alot.

We had shot several hundred shots, when the radio starting cutting out.

After the electrical team spent time figuring out what was up, and working on the EMC type issues, we had our answer.

We've made a 120 lbs, mobile Van De Graff generator. Foam balls, foam rollers, plastic wheels, PVC frame, and high RPMs... And once we came up with this theory, everyone started remembering... "Hey, that's why the robot shocked me!" and "Oh yeah... that explains the shocks."

Anyway... anyone else experience this???

[Bill_Hancoc]

yeah i think i noticed this a few times on our bot too. very keen observation

[Chriszuma]

You could use this property to your advantage.... "Accidentally" give other robots a massive electrical shock... or judges.....

[Mike AA]

We haven't had this problem this year but last year every time we would walk away to get a part and return while it was being worked on we would get a little zap and could see the sparks from fingers or metal tool to the robot. But this was totally the effect from a very dry room and very old, dry carpet. Solved this by making the floor damp. Maybe you need to wipe down your PVC?

-Mike

[pyroslev]

That would explaint the increased snaps.

Normally, we get little shocks. However, the snaps are like lightning bolts. We attributed it to static electricity and the cold, but thist makes more sense.

[Alex Burman]

I've been getting that too, even before the robot was being put together. It was weird, I thought it was just part of global warming or something. The increase in static electricity in the environment. (I've been watching too many dooms day movies)

[Joe J.]

I thought Icarus was shocking me more than any of the other robots did.

[Wayne Doenges]

FYI, before touching the electronics, touch your robot first and discharge the static.
If you use plexiglas or other polycarbonate parts you will notice that they get dirtier faster from the static build up.
Static plays havoc with electronics. I should know, I work in electronic control board factory and we a VERY conscientious about static ESD shoes, and smock). Our floor is a special ESD floor.
I wonder if FIRST will let us use a drag chain on the bottom of our robot?

[Not2B]

Time to stea - uh - liberate some static spurs from the plant.

[MaxS]

Our robot likes to shock people too. It has knocked out three encoders and a speed controller. We are experimenting with drag chains to transfer the shock to the carpet. I cannot imagine FIRST banning them. After all, it is within the box. Last year our robot had a chain hanging down to allow our robot to be touching the inside of the triangles.

[Rickertsen2]

It seems to me that if you have accidentally created a van de graff generator then you are making an area of high and low charge. put some metal bristles that contact the areas of high and low charge and connect them through a wire.

[Kevin Sevcik]

Rick,

Most probably the offsetting charge is in fact being shot out of the robot in the form of foam balls. Which makes one wonder if enough teams doing this could start building serious charges up on the balls themselves. And thus start tossing around small foam lightning bolts.

[pathew100]

Yeah, our robot wacks us pretty good. The charge is building up in our metal frame and pvc and it's knocking out the radio connection when it discharges.

Here's my theory, the metal on the DB9 connector is the ground shielding of the cable, so it is the easiest place for the charge to jump to. The radio is mounted so the connector was 1/4" or so away from the pvc or metal frame. We put some electrical tape on the exposed metal on the DB9 connector that plugs in to the radio, hopefully this will insulate it enough.

Otherwise we will try dragging something on the carpet or suspending the radio in some sort of zip tie web so it is not hard mounted to the pvc or metal.

[Nitroxextreme]

You would think that FIRST would have thought of the electrical part with the foam balls. I mean sure they could say it was a twist we have to deal with.

However, we have been getting some portions when our radio gets "stuck" not working. This is the first explanation that makes any sense. We have even gotten some weird RC errors.

[Mike AA]

Originally Posted by Mike AA

We haven't had this problem this year but last year every time we would walk away to get a part and return while it was being worked on we would get a little zap and could see the sparks from fingers or metal tool to the robot. But this was totally the effect from a very dry room and very old, dry carpet. Solved this by making the floor damp. Maybe you need to wipe down your PVC?

-Mike

To correct myself, after further testing we too had this problem, during testing saturday night my dad had his finger just slightly off the edge of the Aluminum frame and would get a zap about every other ball.

Likely in purdue we will try a dragging chain or something. It seems it would be VERY bad for the controler to have all this static.

-Mike