What sort of depth resolution do you need?
You can get 'Pencil-beam' (15 degree beam width) ultrasonic transducers (like http://www.robotshop.com/devantech-srf235-pencil-beam-range-1.html), but they aren't cheap. The distance range is 10cm to 120cm.
What sort of depth resolution do you need?
You can get 'Pencil-beam' (15 degree beam width) ultrasonic transducers (like http://www.robotshop.com/devantech-srf235-pencil-beam-range-1.html), but they aren't cheap. The distance range is 10cm to 120cm.