Russell I havent read all the replies...but looke at doing a logigtech or like system that the user has a tranducer on the head and a reciever (ultrasonic) mounted above to determine position. Email me direct if you want more info. _________________________________________________________________ Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads