Re: How will FIRST measure muzzle velocity?
 

http://forums.usfirst.org/showthread.php?t=122

Plain and simple even FIRST doesn't know.

Re: How will FIRST measure muzzle velocity?
 

well they know, they just don't want to release it until ship date comes (39 days) so people can't try to design around the method they plan on using. I'm also guessing they may have multiple methods too, that way its twice as hard to beat the system.

Re: How will FIRST measure muzzle velocity?
 

Hate to sidetrack, but that is the offical QA forum? How did you find it and why isnet it linked to from http://www.usfirst.org/robotics/2006/qa.htm?

Just curious if we can point everyone in this thread http://www.chiefdelphi.com/forums/sh...ad.php?t=41762
to that link.

Re: How will FIRST measure muzzle velocity?
 

It is indeed the official Q&A forum, and the link on the FIRST site is just out of date. It was the original link they gave during the first weekend, and that is when they got bombarded with Q's from people, and A's from non GDC people. That is why the new system which your team leader should have access too was set into place. And yes they people in that other thread probably already know whats going on, they just don't seem like it much.

Re: How will FIRST measure muzzle velocity?
 

My main question is this:
if your robots shooter has the ABILITY to go past 12 m/s are you still in trouble? i mean even if you program it to slow down the motors so that it doesn't exceed 12 m/s?

Re: How will FIRST measure muzzle velocity?
 

The judges could use a simple chronograph to measure muzzle velocity.

Re: How will FIRST measure muzzle velocity?
 

It seems to me that measuring muzzle velocity is almost a trivial exercise with two light sensors (in fact the ones in the kit will do it!). To build a portable, wireless clip-on widget about a 20 cm long that mounts to the exit point of the muzzle in line with the exit vector only need work in the millisecond framework - a long time by today's electronics standards. Surely the FIRST Fathers could build a couple of these using only 5% of their brainpower.

Now...not that anyone would...but what prevents anyone from testing at the 80% speed and running up to 100% during play...? (Please don't pelt me with poofs for even thinking this...)

Re: How will FIRST measure muzzle velocity?
 

I think this gets right to the heart of <S02>. As I said earlier in this thread, the muzzle velocity limit is a (game) safety rule, not a robot rule. Compliance cannot be policed by robot inspectors because inspectors cannot be sure that they are witnessing the robot's maximum possible muzzle velocity.

The head referee must make the call when an unsafe shot (as defined in <S02>) occurs on the field, impose the prescribed penalties, and require the team to correct the robot so that it doesn't repeat the unsafe shot.

Re: How will FIRST measure muzzle velocity?
 

1 mile=5280 ft

5280
* 12(inches per foot)
------------------------

= 63360(inches per mile)
* 20(velocity robot shoots(mph))
---------------------------------

=1267200(inches per hour)/3600(seconds in an hour)
--------------------------------------------

= 352 inches per second.

(1/352)*7(diameter of ball)=0.0198863636363

in laymens terms it takes about .02 seconds to pass through the sensor at 20 miles per hour.

using what I did to calculate, you can work backward from the time it takes to pass through the sensor to figure out your velocity.

http://photobucket.com/albums/f327/X...t=100_6574.jpg
http://photobucket.com/albums/f327/X...t=100_6575.jpg