Sonic distance-measuring device

摘要

A sonic distance-measuring device (10) for use in air includes three transducers (14, 16, and 18) in an array of transducers, which are driven in a predetermined phase relationship so as to achieve a beam width that is substantially less than that which can be achieved by any of the transducers individually. To enable the user to aim the device (10) effectively, a lamp (20) is provided to shine along the sonic beam and thus help the user direct the beam at a desired target. To conserve energy and increase the ability to distinguish the light beam from ambient light, the lamp (20) is pulsed rather than driven steadily.