Sacramento State Management & Venue Problems


If you need to connect more digital sensors like limit switches or even QEs there is a temporary workaround:

DM me if you have questions and want to discuss specific sensor allocation with that method.

It is great that you are trying to use Vision sensor! But I would be very cautious about its performance at Worlds, since it is the first year it was released and not all quirks had been discovered and fixed yet. You definitely need plan B for it…


Thanks for the post, OP!

In the weeks leading up to Sacramento, our team worked overtime and put in massive amounts of effort in developing a high scoring yet reliable programming skills routine. We eventually achieved a consistent 26 point routine using line sensors for sensing caps, and the vision sensor for shooting flags.

However, when we arrived at states, all our efforts were instantly thrown down the drain due to the presence of direct sunlight on the skills field. The sun saturated the readings of the vision sensor and completely disabled the line sensors causing not only our programming skills to fail but our match autonomous as well.

Our programming skills were reduced from 26 to a measly 2 points. We were devastated by the lack of understanding that the EP had for our situation, and felt that it was terribly unfair that our efforts had come to nothing just because of the venue.

Looking back on the situation, I do wish that we had had a plan B! But I guess we could thank the EP for teaching us a valuable lesson, and we’ll be sure to implement some sort of redundancy in the future.

Enjoy the video :))

5327S Skills 26 Point autonomous (killed by sunlight)


Don’t get me wrong here, but I actually like the venue with light coming in (I am biased, I work in a room with floor to ceiling southern facing windows).

Lighting situations will vary from venue to venue. This may be an extreme, or maybe not. The goal is for students to learn about the limitations of the components they are using and the range of environments in which they will operate. For example, cars operate from -40 F below to above 120 F…

No where in the Game Manual does it specify the lighting environments for competition. Anecdotally, we know from past competition seasons that sensors can be difficult to use in different venues. As others have mentioned, considering alternative solutions is worth it, so on competition day, you might have to implement a different plan quickly.

I know my MS team was considering light sensor for ball detection in intake as a possibility, but there was a lot of variability , but a limit switch appeared to them a better solution. I am sure if they failed with one, they would go back to the other because it was part of their list of what is possible.

Glad you are moving up to Worlds, I would not put too much salt on the EP. Worlds had issues with fields during Skyrise, but by the time they figured it out, they could not change the environment since too many teams had been impacted by it as a flaw.


Definitely an error by the EP for not working through this with you. However, I place most of the blame on VEX for not supplying modulated sensors for VRC and IQ. This whole calibrate and pray approach is a terrible way to introduce kids to sensor systems when there is a perfectly good, and pretty cheap, way to fix it. Saturation is one thing, the EP should fix that, but general changes in light conditions should be handled by the sensor itself so students get robust values.


Imagine doing skills at states. :slight_smile:


I really don’t like how this thread turned from the fact that the EP/Whoever was working with them didn’t take light into account and didn’t have the ability to fix it.

I have talked to the DVHS (5776) teams for years, I highly doubt this was their first and only way to track the ball, but when this same system works at every other venue they attended and even on different fields where the light wasn’t a problem at the same event, I think that is too much to take into account.

Yes in the future they will have to deal with redundancies in workplaces but when they have used all of the legacy ports available, there really isn’t much there for them to do.

At Arizona States we ran HS matches on three fields, while going through matches we noticed that one of the fields was causing many more disconnects with V5 than the other fields (me being the head ref). So when a couple teams came up before eliminations asked to not use that field we conferred and decided to run only on the other two fields for elims. So yes, sometimes things happen, but as volunteers and EP’s, we should strive (and I know most EP’s in our region do) to not have outside factors affect competition or skills play.


Thanks Justin. We’ve definitely experimented with different sensors in the past and found that line sensors were the most effective and port-efficient method of tracking balls. And in our 5 months of using our robot, we’ve never had a single issue with them at regionals. It should be quite embarrassing for RECF as a whole that they can’t maintain Regional Tournament standards at a State Championship Event.


To change gears here, what can be done for other teams to prevent these types of problems?
In the real world, redundant safeties are everywhere. Very little crucial components rely only on one thing. As others have said, having a plan B is a really good idea.
I would’ve used a potentiometer, encoder with PID, or even a limit switch if things went wrong. But that’s more effort than should be necessary.
So now I’m left to wonder if making an anti slip light shield would’ve helped. One thing I’m personally good at is improvisation and adaptation. While you shouldn’t need to use these skills outside of what you could’ve controlled (which I applaud you for trying to do), sometimes there’s no other choice.

If this thread has done nothing else, I hope it raises awareness to other EPs about lighting concerns for the few World qualifiers left, and furthermore for future events.


Thanks for the OP Sid.

First, congrats on your qualification to worlds! As a competitor at Google, I can testify that your programming skills routine was one of the best and cleanest I’ve seen all year, and a small field variance shouldn’t have caused it to malfunction. But massive overexposure to direct sunlight? That’ll do it.

There was a similar problem at SD states. The fields were set up backwards, so the flags faced the same direction as the red and blue bleachers and the event staff, who were all wearing red shirts. One team with a vision sensor asked event staff if he could purchase a big white sheet to put behind the skills field, which would help his vision sensor. The event staff gave him the ok, so his adult adviser went out and bought a huge paper sheet. Upon the adviser’s return a few hours later, the event staff changed their mind and said he could not put the sheet behind the field, and then denied that they had ever said he could.

So obviously we can point fingers and accuse individual people of being idiots and so on, but I think this reflects a bigger problem. There need to be guidelines in place for standard fields. Lighting, background, properties of game elements, quality of floor tiles, etc. In games like ITZ and SS, antistatic on the field floors significantly changed gameplay, this year the variable stiffness of flags has led to a lot of inconsistency, and of course bathing a field in direct sunlight when teams rely on color, line, and vision sensors is absurd. Vex needs to put guidelines in place and make their products correctly, and the adults that host events need to be responsive to the requests of students, who are ultimately a lot more invested in the program than most of them are.

I’ll be leaving this program in a month and a half, but a lot of people here will be in vex for another year, two, or five. Getting these things right would be awesome.


We should encourage teams to try using sensors and attempt more sophisticated programming. Younger teams that encounter a situation like the one that occurred in Sacramento are likely to react by rejecting the use of the line sensor, or sensors in general on their next robot. This would be especially true if other teams from the same school, that had simple manual robots, fared better in the same situation. That’s not what we want.


I think it would be smarter if they had made the netting solid, to block out any background color distractions…


Unfortunately, these variances are bound to occur and are pretty much out of any competitor’s control. As much as I hate these imperfections, including BO1, I think this is something that VEX competitors will have to deal with. One single instance for one team won’t change VEX’s mind about lighting issues or flag and field defects. I guess being a part of the VEX competition is to embrace the rules that we, competitors, can’t control, whether we hate them or not.



But do we embrace them, or do we lean on vex to fix them? Vex has made a lot of changes in the last few years that everyone seems to like, notably by introducing APs, 2 team alliances in elims, and v5, and they will continue to strive to be better, out of greed if nothing else. But they have also created a pretty abysmal game this year, introduced bo1, gotten rid of the world skills system, and so on. They’ve done a lot, but there’s a lot that they still need to do. And if we continue to give them honest feedback, maybe they’ll keep working.


Most of what you are listing was implemented by RECF - a non-profit corporation - not VEX. Non-profit companies do not act out of greed since there is no profit motive.


Non-profit organizations DO pay their employees. And any left over profit goes back into the organization instead of shareholders. They DO still have a financial incentive.


Yes, but it’s hard for me to ascribe the attribute “greed” to a non-profit corporation. Greed is a people trait and no one is getting rich working at or running a non-proft organization.


But I am sure you must have heard of or came across executives making use of the name of non-profit to benefit themselves. No?

Or maybe it only happened outside US…


Really? Hospitals are non-profit and plenty of people get rich working there.

RECF and VEX, to me, are very loosely separated. They benefit each other, have very tight ties, all that. I am OK with that and hope they make all the money they can, but let’s not kid ourselves that they are independent.


Roger Goodell comes to mind, but they finally gave that up


And this came to my mind…