Abstract: 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.

Abstract: A laser light receiver is provided with an integral laser distance measurement (LDM) device for measuring the distance from a laser plane of a desired elevation to a desired physical target point to be measured on a jobsite. The laser receiver can be combined with a gravity reference device, so that the laser receiver does not necessarily have to be held plumb to a desired target point, when determining the relative elevation of the laser receiver between a rotating beam of laser light and the target point; it can also acquire multiple samples of positions and automatically take a vertical measurement and store that result for later readout. The laser receiver can be further combined with a GPS receiver, to acquire latitude and longitude data, and then in combination act as a three-dimensional transducer that is more accurate in the vertical direction than a GPS receiver alone is capable of.

Abstract: A modulated laser light detector that converts laser light energy into electrical signals which exhibit a frequency that is substantially the same as the laser light modulation frequency, in which these signals allow the detector unit to determine a position where the laser light is impacting upon a photodiode array. A superheterodyne receiver circuit is used to provide high gain at an improved signal-to-noise ratio to improve the range at which the modulated laser light signal can be reliably detected. Various types of signal detection circuits are available. Various processing algorithms are disclosed, including a Discrete Fourier Transform with a simplified computational algorithm for use with a low-power processor device.

Abstract: A modulated laser light detector that converts laser light energy into electrical signals which exhibit a frequency that is substantially the same as the laser light modulation frequency, in which these signals allow the detector unit to determine a position where the laser light is impacting upon a photodiode array. A synchronous rectifier circuit is provided which, by use of a phase locked loop, converts a full-wave analog signal representative of the modulated laser energy into a half-wave analog signal, which is filtered and demodulated to generate a DC level that is indicative of the strength of the received laser light energy. At least two channels of these signals are used to determine the impacting position of the laser light energy.

Abstract: A hand-held laser detector clamp apparatus is provided for use in attachment against virtually all available sizes and shapes of members found on construction sites and in surveying applications. A reversible jaw adapter that contains both a “flat” face and a “ramped” face is attached to a travelling clamp jaw with a clamp lead screw. The reversible jaw adapter can be used with either its flat face out or its ramped face out. A detector bracket and detector screw are also provided as part of the clamp apparatus to hold a hand-held laser detector in place. If the flat face of the reversible jaw adapter is oriented so as to be “out,” then the clamp apparatus will generally be most useable in attaching to flat surfaces, such as rectangular rods or boards.

Abstract: An improved level indicating system is provided for use with excavating equipment based upon a family of laser light receivers. In a first embodiment, a laser receiver with a single “long” photocell is mounted directly on the dipperstick of an excavator in a position that is designed to intercept pulses of laser light being emitted by a rotating laser light transmitter, and an angle-sensing sensor is also mounted to the dipperstick. In a second embodiment, a laser receiver with two parallel “long” photocells is mounted directly on the dipperstick, in which the pair of photocells are of sufficient precision to determine the angle of the dipperstick. In a third embodiment, a laser receiver with two parallel photocells is mounted directly on the dipperstick on a “servo mast” that can be re-positioned along the length of the dipperstick. The movable photocells thus can be shorter in length than the “long” photocells used in the second embodiment.

Abstract: An improved photocell configuration is provided to create a more accurate laser receiver that not only is very accurate and flexible in its operational capabilities, but also can greatly reduce the effect of rotational offset due to shading of the photocell. In one embodiment, a very long photocell is provided in which multiple split-cells are used to present a geometry that will tend to negate some of the effects of shading. The shading effects are minimized by having a different active photocell area along each vertical edge of the photocell. In another embodiment, a "segmented" photocell is used, in which the split-cell design of a long photocell is also divided into vertical segments. These segments can be re-configured so that alternating segments comprise a mirror image about the longitudinal of the long photocell. Such an arrangement tends to reduce the effect of rotational offset due to shading to an extremely small percentage of error.

Abstract: A laser light detector is provided which can be used to detect pulsed laser light that is produced by a rotating laser light source on a construction job site. The laser light detector provides an easily-read display which is indicative of the present level or elevation of the laser light detector with respect to the plane of rotating laser light. The laser light detector has a very large dynamic range, while maintaining a very good signal-to-noise ratio, and can, therefore, be used at both short and long distances from the rotating laser light source. The laser light detector is not dependent upon the energy level received of laser light, or by the spot size of laser light as it reaches the light detectors. The laser light detector is available with several options, including dead band adjustment and audible indication of the elevation.

Abstract: A laser light detector is provided which can be used to detect pulsed laser light that is produced by a rotating laser light source on a construction job site. The laser light detector provides an easily-read display which is indicative of the present level or elevation of the laser light detector with respect to the plane of rotating laser light. The laser light detector has a very large dynamic range, while maintaining a very good signal-to-noise ratio, and can, therefore, be used at both short and long distances from the rotating laser light source. The laser light detector is not dependent upon the energy level received of laser light, or by the spot size of laser light as it reaches the light detectors. Multiple discrete steps of elevation indication are provided, which can easily be increased to a larger number of discrete steps, if so desired. The laser light detector is available with several options, including dead band adjustment, normal or offset on-grade displaying, and averaging.

Abstract: A laser light detector is provided which can be used to detect pulsed laser light that is produced by a rotating laser light source on a construction job site. The laser light detector provides an easily-read display which is indicative of the present level or elevation of the laser light detector with respect to the plane of rotating laser light. The laser light detector has a very large dynamic range, while maintaining a very good signal-to-noise ratio, and can, therefore, be used at both short and long distances from the rotating laser light source. The laser light detector is not dependent upon the energy level received of laser light, or by the spot size of laser light as it reaches the light detectors. Multiple discrete steps of elevation indication are provided, which can easily be increased to a larger number of discrete steps, if so desired. The laser light detector is available with several options, including dead band adjustment, normal or offset on-grade displaying, and averaging.