Hey, we just had a competition this past Saturday and during our quarterfinals match, our alliance partner’s V5 brain went white screen. We believe that this was due to a static discharge when one of the opposing robots contacted them. Because finals are best of 1 is there any way that you could get a rematch or are your just screwed?
Thanks for any help in advance,
1069B
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If the brains screen went white, the battery was probably out of charge and could not power the robot, which caused the controller to disconnect.
I think the battery power is a more likely problem. I’ve never heard of a static discharge doing that. Did you see a spark when the two robots made contact?
My high school team had the same issue during the final match of a tournament this weekend. I can confirm they did not have a low battery. The white screen of death from an electrostatic discharge is a known issue with the V5, It most commonly occurs when the robot comes in contact with the field perimeter.
I remember seeing that now, thank you. I read about an EP that simply grounds their field by using the ground from three prong plug near the field. I don’t like the anti-static spray as much because it has the perception of changing how the robot interacts with the field.
They spray it at Worlds, so teams should get used to it. …
I have to disagree with you on this. Virginia is where the fields are grounded and I don’t believe we’ve had disconnects to the level reported from other states. So, if grounding the fields is equally as effective as using anti-static spray, grounding is better for the following reasons:
- It is cheaper. Grounding is a one-time solution. You need to continue to purchase anti-static spray.
- It is more consistent. Grounding will maintain its effectiveness. Anti-static spray must be re-applied. It is probably not as effective right before a reapplication.
- It does not impact robot performance. The performance of a robot will be impacted by anti-static spray. Plus, this will vary from field to to field depending upon how much was applied and when it was applied. Grounding would lead to more consistent performance.
So instead of just “living with it” we should find the most effective, least impactful solution and use it. This is really not an emotional argument. Grounding versus anti-static spray can be proven out with side-by-side tests. Just anecdotally, it appears thst grounding is superior. This can be proven scientifically and, perhaps, adopted at Worlds.
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Hey, all I was saying is that at Worlds, they spray fields, it is sluggish, teams should not be surprised. If a regional or state is spraying their fields, they are doing teams a favor by preparing them for the conditions at Worlds… no more, no less.
Grounding may be a better solution, but guess what - that is not what they do at Worlds… yet… then again they may change that.
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Peace!
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Our alliance partner was also pushed into the field perimeter during the contact with the opposing team’s robot. But the main question was we lost the match because their robot went dead. The field was sprayed but not grounded, is there any grounds to ask for a rematch because finals are only best of 1?
1069B
Can someone explain, in precise detail, how grounding the field helps? I’ve dealt with static issues before (2003 FRC was particularly bad) and despite tons of research it still seems like a bit of voodoo to me.
Specifically in this case, though - I can understand that grounding the field perimeter would prevent that perimeter from building up a charge and instead leave it at ground potential. But what stops the robots from building up a charge as the rubber wheels turn on the foam tiles? To me that’s the real cause of the issue. If those robots build up a charge, there will still be a big discharge when the robot contacts the field frame.
The static spray, as I understand it, works differently, by simply preventing a charge build-up in the first place.
Finally, I will say that I’m not sure that connecting the field frames to the ground plug from an electrical outlet is such a great idea. For one, it may well violate code, and for another it could be dangerous. There are cases where (due to faults elsewhere in the building electrical system) a ground plug could have a voltage potential (of course this shouldn’t happen, but I’m sure we’ve all seen some pretty decrepit schools and building with well-used outlets and such). It’s one thing to do something like that in your own home, but it’s another thing altogether to essentially build an unregulated electrical device and attach it to a commercial building power system, and then let kids play around it. From an insurance standpoint, I can’t see Worlds doing this without some sort of sign off or certification by some proper authority.
Unfortunately, I don’t have the technical details. Hopefully, someone from Virginia in the know will respond.
Edited: the thought of a building not being grounded properly is terrifying! Yes, that scenario could happen - just hope it is highly unlikely. Regardless of grounding the fields or not.
Fix the problem and not the symptom. I like it.
I have waited for four and a half years to see an EP write these exact sentences. Thank you!!!
Now let’s talk about how this sentence pertains to the World Skills Ranking and Bo1.
Jk, I’m gonna save that for another day.
But more generally I agree with you. Grounding the field is just a better solution. Antistatic pretty seriously affected teams at Worlds the past 2 years, and grounding produces the same results at lower cost, with less work, and with less effect on the robots competing.
Are we … wait for it … agreeing on something?
LOL
Hey, my thing is I love seeing fair, consistent play with rules that favor competitors’ experience and help the best teams win. If grounding the field gets that done better than antistatic or nothing, I’m all in.
Citation needed. Static is highly unpredictable - it depends heavily on many factors such as the local humidity level in the building, which will vary day by day even in the same venue. Because of this, simply seeing less trouble when using a grounded field does not prove that it works better.
You get the discharge when the charge that has built up on the robot finds a path to ground. Either by touching it, in which case your body will be the path to ground, or by touching the field perimeter. So grounding the field perimeter may provide a better path to ground but should not resolve issues with ESD,
some discussion here.
https://vexforum.com/t/esd-my-thoughts/23332/1
as always
We have here a question of correlation or causality - is ESD causing communication loss and port meltdown? or is it just a coincidence?
There is currently no evidence presented in scientific way to determine this. Right now it is all anecdotal - and worse, used to make statements that presumed to be factual.
As for fields being sprayed making the tiles “stickier” that is pretty well understood, and will be a “pre-existing” situation at Worlds (at least, in the past few years). So those programmed routines that are timed based are likely to fail compared to those who measure displacement.
So far, our practice fields with kids constantly getting zapped (fun to watch a middle schooler jump back when picking up their robot ) none of it has resulted in loss of communication nor port loss. Does that prove anything? Not so much, just another piece of anecdotal information presenting itself as engineering fact.
It would not be a reason to replay the match since all robots on the field were subjected to the same conditions.
Replays would be done in cases of field control failure.