with an accelerometer, does it give you live feed back on how fast your robot is moving and where it is moving? or do you have to plug the robot in and download it off? i have never used one or have one but i would like to try one out. is there a way to get the information from that to my iTouch instantly? or can i have a netbook next to the field as i coach?
No, no, No, Maybe(not “instantly” though) , not that I know of but you could ask the Q&A for competition rulings.
Try reading the Inventors Guide on the Vex product web page.
The Vex accelerometer plugs into 1 or 2 (or 3?) analog input ports on a Vex CPU, and provides a ~10bit value for acceleration&gravity. A robot moving at constant velocity will read zero. A robot that is tipping, or turning will have a reading. It will take some programming to integrate the acceleration to get velocity, and integrate again to get position.
I’ve not seen any posts of people who were successful in getting position.
For College Competition (sensors unlimited), there are 9degree of Measurement packages with integrated CPU filtering from SparcFun or DIY drones.
If you want information on how to get position via the accelerometer, check out these two posts on the robotc forums:
http://robotc.net/forums/viewtopic.php?f=11&t=2962
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Me neither. I’ve tried to do it as well, but came to the conclusion that it is nearly impossible to do it with just the vex accelerometer.