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Unread 18-03-2014, 12:52
Racer26 Racer26 is offline
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Re: FRC Blog - It Wasn’t Against the Rules

Quote:
Originally Posted by Alan Anderson View Post
1) It only knows how many if someone tells it for each match.
2) Optical sensing of goal-traversing balls has been tried before (2006). It wasn't reliable. Even detecting balls that were guaranteed to come through a sensor block one at a time was problematic (2010).
My understanding is that the prematch ref screens require the refs to indicate how many alliance BALLs are on the field.

To your second point and the other poster above?

I used to do volunteer work in racecar timing applications. We used a single photo beam and were able to detect 2 cars crossing the beam together, so long as they did not do so side by side by measuring the length of the occlusion. If it was longer than the longest car in the field, you knew it was 2 cars.

In the case of the 2014 FRC goals, the low are easy to deal with, as only one ball can cross the plane of the alliance wall at a time there. In the high goal, if you orient an array of sensors perpendicular to the floor, spaced across the width of the goal such that a ball will always break exactly two of the sensors, it becomes simple to distinguish multiple balls crossing the opening.

Just because we have been unsuccessful in FRC applications before does not mean it isn't possible to do.
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