Sympton: When using the radio to move the robot around we experience intermittant motor activity; cuts off and on but not in a consistent pattern. Very erratic and causes the robot move in a very herky-jerky motion and is nearly useless.
These symptons do NOT appear under autonomous mode or when tethered; motor runs very strong.
So, I have two questions. First, anyone else ever experience this? Second, any ideas what may cause this?
Thanks!
One question, did this happen at a compitition while on the playing field?
EDIT: points to below post dez beat me 2 it
replace the cables that connect your radio from the RC and also radio to the oi, sometimes they can get damaged from constant use and also see if there might be any visible damage to the oi, rc or radios.
My team experienced this at competition. If this is not your first year as a team, then make sure that the radio transmitter and receiver you are using are from THIS YEAR. We accidentally had last year’s transmitter hooked up, which cost us a lot. This year’s radios should have blue text on them.
Yep, it was during the Houston Regionals. I’ll have to check which radio was on the robot; we did experience the problem with two different radios. But, that still doesn’t mean the wrong one was on the bot.
Talk about a frustrating day!
Sean
Innovation FIRST representatives monitor radio signals. They are also very helpful in fixing problems like these. You may want to have one of the reps stop by your pits at nationals if you are unable to determine the problem. MY experiences with them have been very positive.
if this happened somewhere besides an event I would say that someone else is using your frequency - one thing to keep an eye on is the radio link LED on the OI
if it keeps turning red, you are losing your link - either someone else is on the same channel, or something is wrong with your transmitters (could be at the OI or on the bot, either one)
This happened to our team during the first qualification match at the Canadian regional. It’s too bad too 'cause we would have won the round easily: it was two vs one, and both of our robots were disabled from the getgo. Our alliances had an untested autonomous which gave them a code error (probably an infinite loop) so they were immobile for the round. And we had that radio problem. To the best of my recollection, the “receiving” light would blink for a few seconds, then cut out for a few seconds. It was very aggravating; couldn’t really do anything.
We tested everything before the match, and the radio worked fine in the practice area setup in the pits. But when both of our robots got on the field, BOTH of us seemed to have the same radio error lights come up. I don’t know if our alliance partner would have had the same error while driving around though 'cause of that code error. We took the robot back to the practice area after the loss, had the same problem, and the Innovation FIRST guy couldn’t figure it out. I think we just tightened our connections and then it was working fine.
What cheeses me off the most though is that when both of our robots were having the same error lights when we were setting up on the field, the FIRST employees tried to fix things… they had us setup our tether (for some reason beyond me) and we both still had the same radio error lights coming up and they decided to start the match anyways when it seemed as though it was a FIRST error. I understand there’s a schedule to keep to, but it hardly seems fair to me that teams should suffer because of a silly problem like the radio transmissions. If I remember, Simbotics had a radio error too and they were going to start the match anyways, but then their field mentor ran out and was adament about delaying the match until they fixed it (which they did) Good for you!
Of course… we all know it’s hard try and make the competition fair… just easier to remember the bad luck you get than the good luck 
if they fixed the problem by tightning the connections ON YOUR BOT then it wasnt a FIRST problem, it was loose connections inside your bot
you cannot hold up a match if something is wrong with YOUR BOT - there are no timeouts in the qualification rounds.
This happened to our team as well. We ran a simple autonomous that was programmed about 10 minutes before our match, and we only tested that the autonomous worked. However, in the switch from autonomous to controlled, a loop or something kept us from driver control so the robot just sat there. It was an agonizing two minutes because I knew that I was the acuse of the problem with the faulty code, and my drivers just sat there trying everything to get it to work. To add insult to injury, the match was replayed because of a problem with the field, so I had to watch this happen twice.
If your robot will boot and run at all, then you can escape code error problems very easily. Simply hit the reset button on your OI after autonomous has ended, and your robot will start back up without the auto mode bit set and you’ll be able to run as normal. I know Chief Delphi had that problem in their last elimination round at SVR and didn’t get reset until about 20 seconds left, and it was painful to see such a good robot go down because of a very fixable problem.
We had a few radio problems on Friday of the Canadian Regional. During our first match of the day, on three separate occasions we lost communication with the robot. Luckily, we only lost the connection for a few seconds and were still able to cap and hang.
After setting up the controls for our second match we noticed that the No Data/Radio red LED was flickering on and off. So as Blair was doing his introductions, I ran over to the Innovation First rep to report the problem. He supplied us with a temporary radio, and the problem was solved.
My advice to any teams who notice these types of radio problems is to go straight to Innovation First. Their staff is extremely knowledgable and helpful. They will go to great lengths to solve your problem. Also, make sure you check all of your connections. Many teams at the Canadian Regional reported radio problems, which ended up to be caused by loose connections. (Our team included)
The Innovation First rep. was incredibly useful not only with our robot on the field, but with troubleshooting our (now-defunct) IR guidance system. Back in Pittsburgh he was checking the beacons every time our team was up, and was gving us info on telemetry he was getting to help us out after many of the matches. As usual, he was very helpful at the Canadian Regional as well. And yeah, we got our radio cable knocked out because someone forgot to use the thumbscrews. Good thing we won that match anyway.
That would have been good to know, thank’s for the information.
We had this problem last year and a bit again this year. Then we wisened up. Theres three things:
A) Keep the radio away from any motors. They create interferiance (yes, I know I can’t spell).
B) If you have a shell or a cage of some sort made out of metal, put the reciever outside that (the metal in the frame will create a ferridite cage thereby weakening or blocking most electormagnetic waves).
C) Make sure the two antennae (the transmitter and the reciever) are parallel. If they are perpendicualr, it harms the quality of reception.
-Kesich
P.S. And it did hurt when chief del phi didnt reset. We (1097, 114, and 47) could have won that match and probably made it to the finals. But you know what, it was still fun and it was just a simple mistake. No hard feelings.
I am the lead sponsor for the team which started this thread.
The discussion about the reset button on the RC brings up possibly a related issue we had at the competition in addition to the erratic performance on the field. When the round ended or even in the pits on tether, after shutting down power to the robot the team color LEDs would continue to blink. They would shut off after one hit the reset on the RC. Are these problems related??? The back-up battery and LEDs being new this year leave me with little experience in their operation.
Thanks,
APS 
when you turn off the main battery the backup battery continues to power the RC (and team color LEDS)
think about it - thats what the backup battery is for, to keep the RC running when the main power dips
so how does the RC know you actully wanted to turn the main battery off?
ans: you hit the reset button.
We found our that reset turns off the RC by accident. Before, we would pull out the back-up battery to cut off power, which led to a loose connection in the back-up battery.
As someone said before, the problem might be in someone else on your frequency. That sounded exactly like what happen once when we were running two robots in one room without realizing it.
The frequency problem affected us last year. About 10 seconds into the match the robot stopped suddenly. No matter what we did, it would not move. An IFI representative said that the OI was sending data, but the RC was not getting it. Turns out that either someone was running a robot on the practice field or in the pits with a radio, or some other radio signal (RC cars were running around everywhere)