Field controllers disconnecting at skills competition

We have had some issues at the last two competitions with field controllers disconnecting.
At one skills our team robot kept disconnecting the used brain as field controller, other teams also seemed to have the same problems. It was impossible to do proper skills and autonomous skills. They were using a fild controll on a v5 brain. There were no error messages displaying on the screen, Following week at another competition, our team had the same issue, they tried to run autonomous 3 times and each one disconnected also during skills it was keep disconnecting. This time there was a red screen on the controller that said, “robot link lost”. After competition with no change to robot our team had used brain as field control and can’t reproduce disconnect issue, that makes us think it’s not our robot. Who can we trouble shoot this and prevent it from happening again. It is very discouraging spending many hours/days programming skills autonomous just to get to competition and get disconnected.

We have been using V5 Brains using the Skills app for last two seasons. Teams find it very effective. One thing that can be problematic is sometimes the cables get worn and misbehave.

If this was at our events in Framingham, let me know - alert me (the EP) and we will make sure you get opportunity to show your robots capabilities.

Yes it was at Framingham that was when brain was used as controller. Then we competed at Killingly they did not use brain as controller, and it was also disconnecting. We tried it back at our place with brain controller and it worked every time. Kind of lost since we trying to replicate the behavior and we can’t, and we want to prevent this in the future.

You can have your coach email me team number, I can do more refined research.

Did your head to head matches go ok?

What info is logged in your Brains event log? It should give some clue as to whether it was a field disconnect or radio drop … two scenarios.

Do you use manual competition switch to test at your workshop?

killingly did they used Vexnet field control?

I will see if the Skills brain here have info in their event log

We use the quad manual switch controller and a timer (Since we make fields do skills across long breaks / lunch / etc) Never a problem in over a decade.

Work with @lacsap he will figure it out.

There is one good feature of having teams use a stand alone V5 Field control for skills - the team controls when they start their runs and when they stop, thereby giving an accurate stop time - vs verbal communication to skills referee and losing a second or two due to human reaction time.

As I oft say, we are not perfect and as EP or Head Referee I will work with teams to sort stuff out. It is a learning process for all.

We also had some V5 disconnect issues on skills fields at our competition 2 weeks ago (Purdue SIGBots). I was running around coordinating things so I didn’t get the change to officially watch any skills or see this happen but at the 54 team event, I was told it happened about 10 times. We had 1 skills field going all day, and then opened 3 comp fields (on traditional controllers) during lunch. None of the comp fields had DC issues. Not much to add besides just bringing up that it isn’t an isolated issue.

Normal DC issues tend to be helped by mounting radios towards the outside of the bot, making sure it is sturdy with no weird wire pathing to the brain, replacing or checking battery cables, and wiping the brain. We told teams to do this at our comp, but the field managers weren’t aware of many teams having repeated incidents.

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Ok - so question I have - the standalone Skills App that was released before V5 Field Control App - does the Skills App use competition channels or general channels by every robot in the pit area? (friend asking :slight_smile: )

I don’t remember, I would have to fire up that code and check.

The field control app when used by EPs will allow the controller to select the competition channel, this matches what happened with the legacy field control. When we use FC at worlds we pre-assign a channel per division and TM only moves robots to that channel when a field is active, we have to do this as potentially 12 robots are powered up on a three field division and we don’t have enough competition channels to assign two to each one (technically we do, but we also like to keep an unused channel between each competition channel).


Thanks this is helpful and challenges my assumptions about what is possible to run an event… Possible “gotchas” - two divisions with 2 fields each side by side … Skills run in PIT area … 3 competition fields with 2 skills in same area…

I had thought competition density was higher - say six competition fields (skills and head to head ) in one gym size space … no guidance is given to EPs about topology for fields, skills and practice/PIT area.

With state / regionals a month away in the US - what do topologies look like? The design constraints for competition / skills / practice /pits are not well understood for local EPs.

@Foster might be right - run skills on manual match switch with a stopwatch.

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for a typical event there are plenty of competition channels. The controller chooses the channel, when doing that it considers which other channels it can see and what their signal strength is. Ideally the 4 robots in a match will be physically close enough that they will all end up on the same channel (one channel can handle 8 robots).

worlds is a completely different problem, we had a total of 49 division/skills/dome fields and it’s better for us to be able to control radio channel use.


Less is always more. I also print score sheets for the teams, they bring the signed sheets to the TM table. It’s less work for everyone.