US Patent 7414704 Laser light receiver apparatus with automatically adjustable zero-reference point

An improved laser light receiver is provided that senses a laser light beam and determines positional elevation of the laser receiver based on the position where the laser light beam impacts the light sensors of the laser receiver. The laser receiver automatically adjusts its zero-reference point when it senses a magnet that has been mounted on a clamping device that holds the housing of the laser light detector in at least two predetermined attitudes with respect to the clamping device. Thus the invention operates as a clamp-actuated “offset” on-grade mode for the laser receiver.