Steve Smith wrote: > Try an ADXL345 three axis accelerometer should give you the speed and > angle enabling determination of location Why 3 axis? It sounds like this tray is only rocking on one axis. Then again any supposed solution with the limited information given is premature at best. ******************************************************************** Embed Inc, Littleton Massachusetts, http://www.embedinc.com/products (978) 742-9014. Gold level PIC consultants since 2000. -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist