COMM lost way to many times

[G_rupp]

The ESD theory is interesting. Our driver asked how he could keep from getting shocked when he was shutting off the robot at the Kansas City Regional.

[protoserge]

Originally Posted by G_rupp

The ESD theory is interesting. Our driver asked how he could keep from getting shocked when he was shutting off the robot at the Kansas City Regional.

Were they shocked previously?

I am interested in this ESD theory. It sounds very plausible.

[G_rupp]

Originally Posted by protoserge

Were they shocked previously?

I am interested in this ESD theory. It sounds very plausible.

I told him to have the sophomore turn off the robot that way he wouldn't get shocked. He did not say anything about getting shocked at the Colorado Regional. This may have been due to being on the floor with insulation over the ice arena.
We had one reboot during the Colorado Regional. It was in in our last qualification match. The problem was due to a loose battery connection.

I was the one of the CSAs in Colorado. Most of the issues with radios and roboRIOs were due to loose connections or components.

One robot had too much strain relief on the Ethernet cable and when the robot frame twisted, it pulled the RJ-45 all the way to one side and disconnected.

One robot had a battery cable move and unplug the Ethernet cable on the radio when going over a defense

[JDNovak]

I guess I need to complete my theory on how static might create radio problems. The static voltage buildup doesn't cause the problem, it is the sudden discharge of that voltage (ESD) as Greg stated that can create problems.

Years before RFID was mainstream technology I bought and installed a series of antennas to read tags tied to material conveying hoses. They were used to identify where the hoses were plugged. Almost immediately I had lockups and failures. I finally determined that static discharges were being received by the antennas and were actually damaging the receivers. They wouldn't fail immediately but damage the inputs progressively. I was able to tell the damage by measuring input resistance and predict the failures. The problem was totally eliminated by creating paths for the charges to dissipate farther away from the antennas.

We are dealing with a router with antennas here also. The higher the gain the more possibility that the input can be overdriven by large magnetic pulses. The technology has advanced drastically over recent years but theoretically the radio would be the most vulnerable device unless the discharge were to the actual control system. Since it is supposed to be isolated from the frame that is less likely.

This is all just speculation and not based on anything tested with this equipment. Consumer electronic devices are tested for these kinds of events but at some reasonable level. I have seen many fail with the levels of discharge easily produced in plastics handling. The trick is to reduce the potential to an acceptable level.

We need to watch for signs of affects caused by discharges.

[Zagar]

Ah, yes.... like the old lightning straps we used to have on our cars.... We need to find those old rubber straps. lol

What's next? Rockers?

[Bruceb]

wish I had another regional to go to to test this theory.
I can see where these beach tires may have uses in other games and I sure dont want these issues again.
We are running a belt drive on AM plastic belt sprockets. Is that what is creating the charge? And the polyurethane wheels are insulating it so it can build up?
What would the best way to prevent the discharge be?

[olapmonkey]

Maybe one of these...

Gates 90330 Static Strap https://www.amazon.com/dp/B000CRBR8U..._iJy.wb6T3YNQP

And maybe have drive team next year wear tin foil hats?

[billbo911]

Static was not an issue for us this year. Both events we attended had relatively high (for our area) humidity.
In the past we would attach a short piece of chain to the frame and let it drag on the carpet. Only a couple links on the floor were enough.
You should see the looks we would get from inspectors and judges. But, once we explained the logic, they never questioned our approach.
This year we felt that dragging chain was a much higher risk than static build up might cause.
After being FTAA at two separate events, one thing I can say with 100% certainty. The field this year will find and expose any fault your robot has.

[Road Rash]

Originally Posted by JDNovak

Years before RFID was mainstream technology I bought and installed a series of antennas to read tags tied to material conveying hoses. They were used to identify where the hoses were plugged. Almost immediately I had lockups and failures. I finally determined that static discharges were being received by the antennas and were actually damaging the receivers.

I'm not an electrical engineer but I have hands on experience with switching material lines in the dry air of a Wisconsin winter at the sheet extrusion plant I'm employed at. I have felt those static discharges and I can see where it could affect sensitive electronic equipment.

Our forklifts all have short chains making a connection to the ground. Some of our product is corona treated to improve ink adhesion for our customers in the graphics arts industry. Naturally, this makes our finished product contain a charge in spite of our efforts to reduce this with static bar systems further downstream. The chains are there so our forklift operators aren't the ones completing the circuit when exiting the vehicle after lifting the finished product off the end of the sheet stacker.

This is a great thread with a lot of good information to absorb. Our team is weak on electrical and I'm just trying to help them out any way I can.

EDIT: Those of you looking to reduce ESD using a small chain dragging on the ground may want to look into using Static String instead. We also utilize this string to reduce static buildup on our extrusion lines. Copper tinsel works as well and both items should have fewer issues with snagging on obstacles than a chain would.