Quote:
|
Originally Posted by ReggieB
We also got distace sensors for our robot, and i have been trying to find out if they are allowed at competition. They are Sharp GP2D12 . I cannot find the opperating frequency--i know that the IR light is ~800 nm as opposed to FIRST's ~900nm (i think), but i dont think that this will be enough of a difference to avoid interference. Anyone have these/played with these/found them to be a problem/etc?
|
We have these and shelved them when the IR beacon/tracking was introduced at kick-off. Even the appearance of interference would be troublesome.
According to the spec sheet:
- The GP2D12 is at 850 +- 70, so the wavelength with +/- error (780 to 920nm) does overlap the peak 940nm+/- wavelength of the IR beacon LEDs.
- the IR signal generated is at a 20-38Hz rate about 1/3 the 100Hz rate of the beacon.
I'd be worried mostly about clutter obscuring the beacon waveform for other players. It won't cause another robot to home in on you or anything like that, but it can make the beacon signal harder to pick out of the IR clutter. Even though the beacon is BLASTing the IR sensor won't differentiate between stronger and weaker IR. It's just on or off.
You might want to substitute ultrasonic range finders instead.
--edit-- If you decide to use them I would suggest a little experimentation. The IR interference goes both ways. You'll want to test your range finder in the presence of the beacon. Bathing it in IR may trigger it to think there's always an object in front of it.