Bladder motility detection using the Hall effect.

A displacement transducer employing the Hall effect is discussed. The leakage flux density of a permanent magnet is sensed and converted to an output voltage by a Hall crystal providing a low force, undirectional, biological displacement transducer. This device was used to monitor topographical movement of the urinary bladder in dogs and cats during isovolumetric reflex activity, and the results are reported and discussed.