USEFUL INFORMATION ON ULTARSONIC RANGEFINDING:

http://users.picbasic.org/index.php?page=searchprojects

http://users.picbasic.org/projects/u...xperiments.pdf

http://www.picbasic.org/forum/showth...ght=ultrasonic

the picbasic langauge used may have features that dont exist, yet, in PBP, but the underlying techiniques are valid and applicable as are the circuits and design principles.