Faulty Fields

I just want to hear from the other teams that were royaly screwed from the “crossing crystals”, I really thought a “Word Championship” would be more organized or at least have all fields or crystals tested before hand. My team was got by it twice.

Are you still in the game or were you knocked out?

Well it didn’t happen to us at the world championships because we were not there but it happened at our regionals and many teams lost due to frequency problems. Some teams were very upset because they were knocked out prematurely

shirt guy - Tell me more about “Crossing Crystals”. In terms that you would find in the Inventor’s Guide and other official documentation, what do you think was happening.

PS: If you look at the Potomac Vex League thread, you see my reports of problems I saw (in robots that I knew should have worked better (at all)) during today’s web cast.

If it is really that bad, then I think vex should have like dual crysals.

Even if somthing happens, hit a button and you’ve switched.

“Crossing crystals”

I think he meant like interference. How can I watch the webcast by the way? what time did it start/end?

We had problems in match 48. Our alliance worked in autonomous, but in tele-op period, neither robot would get a signal for more than a few seconds at a time. The field crew figured out that there was some interference, fixed the problem,
and scheduled us to replay the match tomorrow.

If you folks don’t start reading these useful messages I just might stop posting them and use my time to eat a bowl of ice cream or kiss my wife instead. :slight_smile:

Go here to see the URL https://vexforum.com/showpost.php?p=9215&postcount=49

PS: When you follow the link above, the place you want to eventually reach (for the webcasts) is here [ the opening ceremony is 9:00 and the DaVinci field reopens for FVC matches at 9:30.think](http://science.ksc.nasa.gov/robotics/. Note tht they won’t start up until around 9:00 or 9:30 tomorrow AM. I )

There may have been some other reasons for peculiar behavior on the FVC fields today, but I believe what was meant by “crossing crystals” is that there MAY have been multiple crystals of the same frequency in use at the same time on the playing fields. I say MAY… because only one field is supposed to be active at a time, while the other field should only be setup for the next match with all robots and transmitters turned off. If a team didn’t follow this procedure given by the field manager then there-in lies the potential for interference.

As far as I know, 3 matches from today will be re-run on tomorrow because of this potential problem. Please don’t ask me which matches because I don’t know.

I must stress to all teams that it is a good practice for them to keep their transmitters and robots TURNED OFF until directed by the field manager to turn them on. This is particularly important for teams queued up for matches that already have their competition crystals. If you must turn it on to reset a mechanism, DO NOT TURN IT ON WITH A CRYSTAL INSTALLED!

The field managers may provide all teams with an updated startup sequence tomorrow morning in an attempt to eliminate all potential sources of interference from queued up teams and the adjacent playing field. Competing teams must do their part however in ensuring that they are not inadvertantly creating the very problem they are complaining about. If you see another team using crystals in the pits or in the dome, remind them that they are to be tethered up. As a matter of fact, there is no need to bring any of your own crystals to the competition because you are not allowed to use them at any time.

Good luck to all teams and I’ll see you all under the dome tomorrow morning.

You would think that VEXLabs would make a couple more crystal kits with one in a higher frequency than 85 and one kit wiith lower frequencies than 65

I did read your post nut I couldn’t get it to work. They may not be able to make the channels any higher or lower because they are outside of the band. AM frequencies have 10 channels, and FM has about 100. There are many variables but what about something like a 2.4gHz system? there are virtually no flaws becuase it runs on 2 channels all the time with an unlimited number of channels to pick from.

Ok with the crossing crystals it is not the FVC organizers fault. Teams who were waiting for matches would turn on their remotes to do stuff to the robot thinking that by being tethered to it they were ok. Well they were still sending out the signals from their controller. Anyways on the second day they fixed the problem and re-ran the bad matches.

They didn’t redo matches at our regional when there was interference. Sometimes only 1 robot would run and they told them to deal.

Guys - This is not picking on anyone, so don’t take it personally.

Let’s please stop talking about “crossing crystals” I am not aware of any such term in electrical engineering, or any other scientific discipline. The crystals were not crossing. The transmitters were interfering with each other.

I want to help you sound like you know what you are talking about when you speak to folks about this, so I’m suggesting that you tell folks that transmitters in the queue (or elsewhere) were transmitting signals that interfered with the match paticipants’ transmitters’ signals.

If you tell an EE or an RF Engineer, or Physicist that crystals were getting crossed, they will probably look at you a bit funny. If you tell them transmitters in the queue were being turned on and were “stepping on” the match signals, they will understand.

It’s important to get this sort of thing correct…


Man… there was something wrong with the competition field…

  1. We lost at least 2 qualification matches based on the field. Our robot either failed to respond or restarted autonomous mode in the middle of the match. Oo
  2. We had a replay a match twice… because of crystal and field errors…

Your lucky they did a rematch, some people were screwed and just lost.

I wish we could have replayed the matches in farmville that were messed up by frequency problems I think the results would be much different.

Most regionals were strapped for time so that’s is most likely the reason why they didn’t re-do matches. At Worlds they planned in time for make up matches.

Teams must realize how difficult it is to run these competitions. As someone who helps run an FLL event it is a huge task, that depends on everyone following all of the proper procdures.
I know several of the people who were running the event and I am sure that they wanted a fair competition for everyone, but still fit in the time line. Remember that FIRST is renting the Georgia Dome and GWCC and their employees. Also the FIRST staff are volunteering their time. I know of one guy who is using three of his 15 vacation days to volunteer there, plus pay for his own transportation and airfare.

These are difficult lessons to learn, that sometimes things don’t go you way even though it is not your fault. An EXTREME is example is when I was hit by a speeding car while I was stopped at a red light. Was it my fault? No. Was my car totaled? Yes. Could we do it over? No

I am sure FIRST will be working on these issues to improve FVC. It is in their best interest. The easiest way to do this follow all of the procedures so that you do not impact others.

We were probably one of the most effected team in the competition: 3 of our 5 matches (1 of which was a practice match, so it is actually 3 of 4 matches) we were completely immobile. This cost us the match in every one of those matches, even keeping another team that should have at least been in the eliminations (3075) from winning a single award! It was 3148 and us (3495) that first brought the field problem to the judges’ awareness on Thursday. Unfortunately, these problems could not be helped, and we were forced to retire the championship because of the unknown problems (do we even know if it was interference?).

FIRST did a great job putting on this event. I know it is a lot of work, and even though there were unexplainable problems at times, the show went on and a superior alliance was chosen as the champions. I might feel better if we had not been chosen on an alliance because we played bad, but the fault was unknown and we didn’t even get to compete. Our team decided that because we could not possibly help an alliance, we would graciously decline any offer into the eliminations, and that is not fun. All of our team members paid upwards of $500 each just to come to this event, and to not get a chance is disheartening. We all hope the problems we encountered this year won’t be seen next year, and thank FIRST for their dedication and commitment to putting on such an immense program.