Quote:
Originally Posted by joshyboy9987
We don't have anything working so far, but we've been working on some code to use the accelerometers and gyro that come in the kit. They can give you both linear acceleration (in two directions) and rotational acceleration. By doing some Calculus, you can use them to get distance pretty simply.
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Prior to last year's competition I messed around with a Vex robot and the 2006 kit accelerometer and gyro. The gyro works fine for angles, and I have yet to have a bad experience using gyros for direction sensing in 3 years using them. However, I don't believe accelerometers (or at least the kit ones) are that great for linear distance measuring.
With the Vex robot, the accelerometer is absurdly sensitive to noise (with the kit accelerometer, touching the robot with my finger was enough to make it angry), and you get innaccurate for distances extremely fast. It may be better with FRC, and if you could get a more reliable accelerometer or a better ADC with more resolution it might be possible, but I would not recommend using the kit accelerometer for distances.
Now for the main thread:
Our team has used pots and limit switches forever, for limiting motion and setting exact positions on arms and whatnot (the most fun of these being an elevator in 2005, where we used a set of switches and a plate that would slide over them to sense 5 different heights). The gyro has started getting used recently on my team and in my opinion is the most beneficial sensor you can use; we use it for turning in autonomous and for driving straight in both autonomous and manual mode (your drivers will thank you!). We installed an accelerometer for tip prevention last year and had already tested and proven code, but never got to use it since we never got to calibrate for that specific sensor. Banner sensors are pretty effective for line detection and can be used as a sensor beam like a garage door with a reflector (I think these used to come in the kit pre-2004).
This year will be a gyro, pots, and limit switches as usual. I think this year's programmers want to try encoders for distance and then a line sensor for detecting the finish line (nice way to tell when you're right under the overpass). I've suggested uses for sonar but with a smaller programming team than normal I think they only want to try one new sensor and stick with encoders.