A sand transport detector which detects the discrete impingements of sand particles on an elongated probe member inserted into the sand. A piezoelectric transducer element is cemented to the probe and produces an output signal when impingement occurs. With an electronic circuit coupled to the transducer,...http://www.google.com.au/patents/US4114063?utm_source=gb-gplus-sharePatent US4114063 - Piezoelectric sediment particle transport detector
