Soccer Ball Sold Out

[Greg McKaskle]

For teams intending to use vision to locate the soccer ball, there are a number of things that may be useful to consider.

1. The soccer ball chosen doesn't have a saturated color that is easy to mask. Robo Cup traditionally uses orange elements to make things easy, but they are starting to move away from that to up the challenge.

2. 3D shapes illuminated with directional lighting produce a huge variation in the shade of the color. Almost half of the ball will be in its own shadow.

3. Bright lights cause specular reflections -- glare. Matte objects have larger blurrier reflections which are a blend of the surface and light color, and shiny objects have smaller, sharper and brighter reflections which tend more towards the light color. In other words, no matter what the color, the field lighting and shop lighting will cause many holes in the image of the ball.

On the positive side, you might consider the background behind the soccer ball. Think of the soccer ball, shadows, etc. punching a hole in the carpet. Especially for autonomous, this seems like it might be a viable approach for locating the ball using the camera.

Greg McKaskle

[MrForbes]

Also the balls are very glossy, very reflective. I expect you'll have a lot of trouble with reflections from the lights in the arena.

[dtengineering]

I'm glad to read that more HS300 balls are on their way. We just had a couple of HS500 balls delivered yesterday and they are, as Jim says, very glossy and their surface finish definitely has a lower coefficient of friction on carpet than the old, beat up ball we were originally testing with.

That said, I'm not sure how long the pristine surface finish will last... probably quite a while, so long as we don't subject the balls to the vicious high speed ball grinder that our first prototype "backspin roller" turned out to be. Who knew AM wheels could melt soccer balls?

A lower speed, higher friction approach appears to work better, and we've had good success using the intake roller off last year's robot with both the new and older balls (about 2" diameter Al tube with McMaster round belting on it, driven by FP motors on a 64:1 reduction, as I recall)

But several soccer players have commented on how glossy the balls are... I'm glad we now have a standard to base our designs on... we'll inflate one ball to 27" circumference and another to 29" so we can test kicking and control at both inflation extremes.

Jason

[Greg Needel]

Originally Posted by dtengineering

I'm glad to read that more HS300 balls are on their way. We just had a couple of HS500 balls delivered yesterday and they are, as Jim says, very glossy and their surface finish definitely has a lower coefficient of friction on carpet than the old, beat up ball we were originally testing with.

That said, I'm not sure how long the pristine surface finish will last... probably quite a while, so long as we don't subject the balls to the vicious high speed ball grinder that our first prototype "backspin roller" turned out to be. Who knew AM wheels could melt soccer balls?

A lower speed, higher friction approach appears to work better, and we've had good success using the intake roller off last year's robot with both the new and older balls (about 2" diameter Al tube with McMaster round belting on it, driven by FP motors on a 64:1 reduction, as I recall)

But several soccer players have commented on how glossy the balls are... I'm glad we now have a standard to base our designs on... we'll inflate one ball to 27" circumference and another to 29" so we can test kicking and control at both inflation extremes.

Jason

Would it be possible for anyone to compare these balls to the wilson hex soccer ball available at walmart? I have already seen this ball as the most common one in people's prototyping pictures and videos.

[MrForbes]

I'd like to compare them, but the Wilson ball is in the fab shop, and the spec ball is in the meeting room! I'll see if I can manage to get them together for a comparison. I also need to remember to get a pressure gage....

[Chris is me]

Personally, I'd rather vision track the goals than the ball. You place the ball where you want to and drive until an IR or ultrasonic sensor on your robot indicates it is properly possessed, then you aim at the goal. Though since there's no particular reason your aim should be different every round, the camera isn't too important.

[MrForbes]

I visited Walmart today and looked at the soccer balls, the white Mitre Cup Final ball seems to have a finish similar to the spec ball. Much closer than the less expensive Wilson ball I bought there.

I did not do any measuring....sorry.....

[TD912]

FYI, it appears they are back in stock:
http://dtisoccer.com/store/index.php...d&productId=17

No more Out Of Stock/Sold Out message!

[MrWibbles]

w00t, more soccer balls!

Is the "White" color the same as "Pearl White" ?

[gyaniv]

GOD...
I almost started crying from laughing while reading it...
Feels good to have Nike as a sponsor that gives you 50balls for free... And not the cheap kind...
So awesome to be us right now...

[PAR_WIG1350]

Originally Posted by dtengineering

I'd happily trade the KoP wheels... especially the rather useless slick ones... for one regulation soccer ball.

Jason

The slick wheels are very useful, especially for smoothing-out 'jumpy' drive trains.

[PAR_WIG1350]

Originally Posted by 1075guy

2010: DTI Soccer Balls are unobtainium, not going back into production till the competitions have started
2009: Orbit balls became unobtainium, Blip Toys wasnt going to manufacture more till after competitions started
2008: Trackballs were DIFFICULT to obtain, but were not so bad because there were so few in the game, and were expensive.
2007: The tubes were not easy to get until after the games were done.
2006: The poof ball manufacturer was blindsided, they got really hard to get
2005: Used game pieces teams could make themselves.
2004: The 5 pt balls became hard to get the exact model, luckily, lots of similar 14" rubber balls exist in high school gymnasiums
2003: The sterilite bins used were unobtainium for months after the competitions.

Thats as far back as i've been involved... FIRST game pieces becoming unobtainium by the second week of January happens regularly. FIRST needs to warn the manufacturers adequately.

Maybe, the manufacturers, even if warned, don't understand the magnitude of the situation because of
-FIRST not making a big deal about it, to keep it a secret and
-the fact no one at the company has ever heard of FIRST or, if some one does, they don't know much about it.
this results, possibly, in the company falsely believing that the increase in sales will be smaller than what it truly is. maybe if FIRST, or the teams, made the game pieces, it would work out better. But then again, in 2005 the issue was that the game pieces were more dangerous than the GDC had anticipated due to their weight.

[m3ch4num470r]

After the DC Regional, team 449 found an issue with not having access to an official ball.

We use a vacuum attachment for grabbing balls. It was working incredibly well with our Size 5 ball back in our school, so we figured it would work well at competition. We adjusted it at competition using our ball, then went out to compete. The vacuum didn't pick up a single ball. Finally, on day two, we went out to the practice field and put a ball against our vacuum opening. Lo and behold, the official soccer ball is larger than ours!

If your robot needs something in precise contact with the ball, please learn from our mistake and remember that the official balls could be a different size than yours, even if you were using a size 5 ball. Take the time to go out to the practice field and adjust your mechanism properly for the official ball on the official field. If your mechanism isn't adjustable, take some time to think about how you might make it adjustable quickly at competition. We were lucky enough to have an 80/20 mount, but I know that a lot of teams are more refined and use welded aluminum.

We also noticed that the ball was bouncier than ours, so we were kicking a little further (no complaints there). Obviously, your mileage will vary based on which ball you used.