I am trying to set up a photo cell thru beam to detect objects and sacks. I tried the light sensor 276-2158 and the Flashlight 276-2210 on each side if the robot, trying to detect a sack breaking the beam. It works with an incandescent (Wal-Mart flashlight), but not a LED light source like the VEX 276-2210 LED Flashlight. Is there a pre LED version of the VEX flashlight that uses incandescent?
I tried using (2) line trackers facing each other at 12” spacing hoping one would be a source and the other the receiver, but I couldn’t make it work.
Should I be wishing for a new VEX legal product, either a photocell that can see the VEX Flashlight or a light that the VEX Light Sensor can see?
Could the Ultrasonic Range Finder accomplish what you’re trying to do? It reports the distance to an object.
If you set it up so that it was pointing at a piece of metal 1 foot away, if it ever reported a distance less than 1 foot then the “beam” would be “broken.”
Hopefully that helps.
If you aren’t doing anything to shield the light sensor from ambient light, it probably won’t be able to detect the difference between ambient and the flashlight.
We used the flashlight and a light sensor to detect balls and barrels last year and it worked perfectly. We were able to detect when a game element was in front of the robot without touching it and we could pick them up without them rolling away.
To shield the sensort from ambient light, we took a square of VEX Adhesive Foam and made a hole in middle, roughly the diameter of the actual photo cell of the light sensor and stuck it to the face of the sensor so it lined up with the photo cell. This was enough to block any light that is was not coming directly at the sensor. Then position the flashlight across from the sensor so it shines directly in to the hole in the foam. You should now be able to get see a clear difference in the signal from the light sensor when the light beam is broken.