Sensor allowed?

If we are using a distance sensor manufactured by Sharp, would we be able to use it on the robot?

[Joe Ross]

See <R71>, most likely yes. Make sure you look at the latest version in team update 5.

[Mark Pettit]

<R71> Additional electronic components for use on the robot must be currently available from or equivalent to
those available from Newark InOne (http://www.newarkinone.com), Future Active (http://www.futureactive.
com), Radio Shack (http://www.radioshack.com) or Digi-Key Corporation
(http://www.digikey.com). The total catalogue value of additional electronic components must not exceed
$200.00 USD. This cost is counted as part of the $ 3,500 limit. No single electronic component shall
have a catalog value of over $100.00 USD.

RTFM.

[seanwitte]

The data sheets for those parts don't include the type of light they use to measure the distance. If they're using modulated IR at the same frequency as the beacons then you cannot use them. The Banner sensors use visible red, maybe these are the same.

[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?

[Mark McLeod]

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.

[Kevin Watson]

Originally Posted by SilverStar

If we are using a distance sensor manufactured by Sharp, would we be able to use it on the robot?

If the device is P/N GP2GD12, then it's probably okay. I know some testing has been done and that it did not interfere with the Vishay infrared sensors. I would confirm it with the FIRST engineering guys.

-Kevin