Re: Where to buy Balls?
 

But this is very, very bad. It says right in the email that the balls we use at the competition will be different than the balls we can buy.

This is *not* good. I think we need to pressure FIRST into finding someone else we can buy from in the meantime.

--Petey

Re: Where to buy Balls?
 

welcome to the world of real engineering!

I think most teams got one of the right 13" balls in the kit - so no matter what other 13" balls you purchase, or end up with, make sure your ball collecting mechanisms are not hyper-dependant on the characteristics of the balls

I would say inflate what you got to 13" diameter, and use the one they came in the KOP as your golden sample. If your machine can work with the KOP ball, and with whatever other 13" balls you ended up with then you will have no problem at the events.

in fact, you will probablly do better than a team that had to fine tune and tweak their machine to get it to work exactly right with one type of ball only.

The balls at the events are going to get scuffed up, partially deflated - they wont all be exactly the same size or have the same flexibility

Plan for it!

Design your bot to be 'gracefull' not finicky :c)

Re: Where to buy Balls?
 

But we accidentally popped the "golden" ball!
:ahh:

I'm not worried about our robot. You're right--if our robot is that finicky, we have a bigger problem than ball size.

The problem is human players. The definite discrepency in weight and probable discrepencies in bounce, trajectory, air resistance, etc., are ones that I'm not sure human players will be able to overcome.

And this doesn't answer the question that I originally came to this thread with:
Has anyone found a more durable ball than the "new" ball? Because we've already popped two even though we've smoothed down the tops of our mobile goal PVC pipes. These stiffer ones break very easily.

--Petey

Re: Where to buy Balls?
 

I just contacted Level One Sports and they said that Champro (the actual manufacturer of the balls) doesn't have any more!!

Good luck finding them any time soon. :rolleyes:

Re: Where to buy Balls?
 

did you measure the circumference when you inflated them? 41 inches?

we have not had any problem with them popping.

Re: Where to buy Balls?
 

They were inflated to the requisite 13".

Did you cap your goalposts with something? We haven't broken any since we capped our PVC goalposts.

--Petey

Re: Where to buy Balls?
 

It is unfortunate that teams have not been able to aquire quantities of the competition-like ball... but, there is a positive lesson here... (Aidan ducks)... in the real world of engineering, the material/object that a machine has to be built to interface with is often not available.... and when it is, specs on the object change mid/post design all the time.

The extreme example of this is evidenced in our friends Spirit and Opportunity. They had to be designed without actual Mars rocks, actual Mars gravity, actual Mars dust... etc.

So - amid your frustration - be sure and teach your team that this is not an insurmountable disaster - but a lesson in real-world engineering.

:)

Aidan (still ducking behind desk...)

Re: Where to buy Balls?
 

Like I said, the greatest problem isn't in engineering, it will be with the human players. Seems we've been forgotten about.

--Petey

Re: Where to buy Balls?
 

Petey -

If you practice basketball at school with a leather bastetball, and your team shows up at some school to play - and they use rubber basketballs - can you play them competitively? Can you play flag football with a leather ball and a nerf? If you always practice with green Wilson tennis balls... and you show up to play someone who brings orange Penn balls... can you still play?

As humans we can adapt very easily and quickly. I don't see this as being a huge problem for human players (yes, on planet Utopia, all human players would practice with the right ball... but they will deal... and still do well).

:)

Aidan

Re: Where to buy Balls?
 

Aidan,
Because of the greater emphasis on the human player...
FIRST should have included a regulation ball in the kit of parts!


Oh wait... THEY DID!!!

JVN

;)

Re: Where to buy Balls?
 

FIRST could have avoided this whole problem if they had just included a good human player in every kit... :D

Tom

Re: Where to buy Balls?
 

With all due respect, your analogy is completely off.

The tennis balls you mentioned will be have the same weight and other dynamics as their counterparts.

Sure, you can play basketball with a street ball and football with a nerf ball, even if you are used to leather balls for both.

But in both cases--especially in the latter rather than the former--you will have a very hard time of it. Have you ever *thrown* a Nerf ball as compared to a real ball? They are extremely dissimilar. In fact, you can't even play the same game with them.

You can play. The question is: how well can you play? I know that our team's human players will probably come out of the S&G subgroup on our team, and we are spending 6 days a week practicing with those balls. Come competition time, we may be able to shoot with 90% accuracy. That's a darn good rate.

Now, say with those other balls--allowing for differences in weight, rebound, aerodynamics, and interaction with the robot and the goal structure itself--you drop down to (I'll be very generous) 60% accuracy. That's a 30% drop. Are you trying to tell me that there is no substantial difference between making 6 out of 10 shots and 9 out of 10 shots? That's 15 points, assuming there is no ball-capping going on.

My team leader said that human beings can adapt as well. So? I don't know about you, but I can't throw off preconditioned muscle memory that easily. There is a half pound difference between the balls. That's like the difference between a baseball and a wiffle ball.

I mean, obviously we're going to deal with it. But it doesn't make me happy that we won't be as prepared as we can be, nor does it fill me with joy that FIRST didn't do enough planning to stockpile the balls beforehand.

Sure, FIRST included a regulation ball in every KOP.
<begin sarcasm>
And that'll be just fine for performing a simulated game or for trying to figure out how many balls you can realistically shoot in 1:45, and with what accuracy. And, of course, it is really great if your team's regulation ball pops.
<end sarcasm>

--Petey

Re: Where to buy Balls?
 

Have you ever played basketball with a men's ball all the time then once in a while change to a women's ball? Its about the same difference, and usually a good player (good human player) can adapt within 20-30 shots. You have all the practice rounds on thursday to establish yourself with this change in weight, and that should be more than enough for your human player.

Re: Where to buy Balls?
 

Good point. I hadn't thought about the practice sessions.

Will they let us use the balls? I wasn't doing FIRST before last year, so I don't know about any of the previous "ball" years. It would seem like FIRST would have some pretty strict rules so someone didn't get killed out there.

--Petey

Re: Where to buy Balls?
 

The thing that irks me the most about this is that noone at Palos sports said anything about it ahead of time. I ordered 18 balls the Tuesday after kickoff, they didn't get shipped until Friday, I called on the following Monday to check on my order, and they didn't get delivered until Thursday. We lost 2 weeks of practice time waiting for the right balls and didn't get them - I could have just gone to Wal-mart and bought generic kickballs.

Still considering whether or not to return them and demand a refund including shipping charges - anybody else thinking about that?