Needed: Very precise light based detector

[de_]

We would like a very narrow beam detection system to detect a ball within 1/4" across the 20" face of (3" inside) our robot. There appears to be lots of inexpensive light detectors but we are having trouble finding a legal narrow beam light source as FIRST prohibits anything with a "laser" description. Unfortunately a low power consumer "laser" pointer would be ideal.

Anyone with any suggestions how to get a (non-laser) led light source into a very narrow beam (for 20") ?

[Jared Russell]

http://www.bannerengineering.com/en-US/

Banner makes all sorts of sensors for this (that don't use lasers). We are using one to detect balls on our robot (QS18 series), and it works great.