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IR Sensor

The Vishay TSOP34840 IR sensor, or simply IR sensor, is used to detect infra-red signals. In FIRST Robotics, this sensor is primarily used during the autonomous mode. It was introduced in 2004, for the game FIRST Frenzy: Raising the Bar, and during kickoff Dean Kamen and Woodie Flowers strongly hinted at its continued importance. The most common setup works by connecting the sensors to interrupt pins, and detecting a certain frequency and pulse-width that the IR beacons were known to emit.

Use in 2004

The 2004 game FIRST Frenzy saw the first use of the IR sensor. During the autonomous mode, there was a ball that had to be knocked over. The robots could not simply stick an apendage out and follow the wall, because bars prevented this. Dead reckoning and line following were still alternatives, – but the new method available was IR tracking. On each side of the field above the ball, IR beacons emitted a specified signal, such that they could be differentiated. Not many teams decided to use the sensors, choosing instead more simple methods, and those that did were not always successful. See Autonomous techniques (2004) for more information in this regard.

Future use (speculation)

At kickoff for the 2004 season, it was strongly hinted that the IR sensors would be back next year, and that it might be necessary to use them. Keep in mind that the following is pure speculation, something the FIRST community seems to love, – even given their track record. However, possible ideas for why this might be the case include this. The robot will have to track a moving target, and since it is not static, dead reckoning simply won’t work. For more on this discussion, see these ChiefDelphi threads ([1], [2]).

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