[Al Skierkiewicz]

Please remember that an accelerometer measures acceleration. (i.e. changes in speed) It does not give an output when the speed has remained constant. These devices use two machined bars with peizo elements mounted to them. When there is acceleration in one axis, the bar deflects in an opposite direction and the peizo outputs a proportional voltage. With a two axis device, you can sense the direction of the acceleration or deccelleration. (negative acceleration) These devices do need some filtering to damp out vibration and other interference. You may want to consider using multiple devices in a bridge configuration to null errors and give the feedback you need for your application. There are some accelerometers available in Digikey and I would recommend reading the manufacturers literature for a more indepth explanation.