Abstract: Apparatus, methods and systems for controlling a dust collecting system are presented. A system includes a plurality of sensors paired to a corresponding plurality of blast gates, and a controller coupled to receive a signal from each of the plurality of blast gates. The sensor non-invasively detects power flow through a tool's power cord. The controller is coupled between a collector and the blast gates. The blast gates may be configured in a star and/or daisy-chained configuration allowing for flexible installation. The controller instructs the collector to turn on and off based on a sensor signal received via a corresponding blast gate.

Abstract: A method and apparatus to detect non-cancelled magnetic field produced when current flows through an electric conductor are provided. The sensor includes multiple coils, which allow the sensor to be arbitrarily oriented and attach to the outside of an electrical power cable. Arbitrary orientation provides for easy of field installation.

Abstract: An implementation of an apparatus and method for sensing electrical wiring, for example, hidden behind a surface such as a wall is provided. The apparatus and method use multiple sensor signals, which may measure electric fields or changes in a dielectric. Pairs of signals are combined and compared to a sensed reference signal. Multiple sensors help in determining a direction or gradient to electrical wiring. Combining or averaging sensed signal before comparing the combined signal to a reference single helps to make the detection of electrical wiring less dependent on the relative orientation between the sensor and the electrical wiring.

Abstract: A method and apparatus to detect non-cancelled magnetic field produced when current flows through an electric conductor are provided. The sensor includes multiple coils, which allow the sensor to be arbitrarily oriented and attach to the outside of an electrical power cable. Arbitrary orientation provides for easy of field installation.

Abstract: An implementation of an apparatus and method for sensing electrical wiring, for example, hidden behind a surface such as a wall is provided. The apparatus and method use multiple sensor signals, which may measure electric fields or changes in a dielectric. Pairs of signals are combined and compared to a sensed reference signal. Multiple sensors help in determining a direction or gradient to electrical wiring. Combining or averaging sensed signal before comparing the combined signal to a reference single helps to make the detection of electrical wiring less dependent on the relative orientation between the sensor and the electrical wiring.

Abstract: An implementation of a direction finding and magnetic nulling metal detector is provided. Some embodiments of the present invention provide for a metal detector having multiple resonant circuits and associated coils for transmitting a primary transmit signal, transmitting a magnetic nulling signal, and receiving a receive signal. A controller includes logic to process the generate the transmit signals and to process the received signal in order to determine a gradient vector along one or two dimensions, a depth and whether or not a metal object is ferrous.

Abstract: A wireless (e.g., radio) system and method for automatic water level maintenance of, e.g., a swimming pool utilizing capacitive liquid level sensing. A reference electrode allows water level sensing independent of the water chemistry or temperature. Capacitive electrodes having areas larger than the reference electrode sense various liquid levels when the liquid covers an area of any sensing electrode equal to the area of the reference electrode. Averaging is incorporated to filter out effects of wind or other disturbances. Upon sensing a given condition, the transmitter transmits a sensed condition to a remote receiver for control of valves and pumps for changing the water level in the pool. The receiver includes safety timers for filling and emptying to protect against equipment failure or communications faults. User selectable identification allows identical such radio systems to operate within proximity to each other. Power saving features are used to extend battery life.

Abstract: A light emitting module and a modular light emitting system with leveling capability. The system relates to light-based (e.g. lower-based) layout tools of the type used in the construction industry. More specifically, the system relates to a modular light emitting system for projection visible patterns, such as dots, lines, cross-lines and other patterns, on one or more distant surfaces for purposes of alignment, construction, verification and the like.

Abstract: A sensor and method that detects a mis-calibration and automatically recalibrates itself without operator intervention. If the sensor determines that it was calibrated over an object such as a stud, the sensor may automatically update the calibration value with a new lower value without operator intervention. This process may repeat until the calibration value is set to a value that represents the wall covering alone without hidden objects behind it.

Abstract: A capacitive sensor including a pendulum for electronically determining an indication of angular offset and a capacitive leveling device having such a capacitive sensor for leveling an associated reference surface. The capacitive sensor detects a difference in capacitance of one or more capacitors on the pendulum and its housing, each capacitor having a first electrode movable apart from a second electrode as the housing tilts relative to the pendulum.

Abstract: A wireless (e.g., radio) system and method for automatic water level maintenance of, e.g., a swimming pool utilizing capacitive liquid level sensing. A reference electrode allows water level sensing independent of the water chemistry or temperature. Capacitive electrodes having areas larger than the reference electrode sense various liquid levels when the liquid covers an area of any sensing electrode equal to the area of the reference electrode. Averaging is incorporated to filter out effects of wind or other disturbances. Upon sensing a given condition, the transmitter transmits a sensed condition to a remote receiver for control of valves and pumps for changing the water level in the pool. The receiver includes safety timers for filling and emptying to protect against equipment failure or communications faults. User selectable identification allows identical such radio systems to operate within proximity to each other. Power saving features are used to extend battery life.

Abstract: A wireless (e.g., radio) system and method for automatic water level maintenance of, e.g., a swimming pool utilizing capacitive liquid level sensing. A reference electrode allows water level sensing independent of the water chemistry or temperature. Capacitive electrodes having areas larger than the reference electrode sense various liquid levels when the liquid covers an area of any sensing electrode equal to the area of the reference electrode. Averaging is incorporated to filter out effects of wind or other disturbances. Upon sensing a given condition, the transmitter transmits a sensed condition to a remote receiver for control of valves and pumps for changing the water level in the pool. The receiver includes safety timers for filling and emptying to protect against equipment failure or communications faults. User selectable identification allows identical such radio systems to operate within proximity to each other. Power saving features are used to extend battery life.

Abstract: A wireless (e.g., radio) system and method for automatic water level maintenance of, e.g., a swimming pool utilizing capacitive liquid level sensing. A reference electrode allows water level sensing independent of the water chemistry or temperature. Capacitive electrodes having areas larger than the reference electrode sense various liquid levels when the liquid covers an area of any sensing electrode equal to the area of the reference electrode. Averaging is incorporated to filter out effects of wind or other disturbances. Upon sensing a given condition, the transmitter transmits a sensed condition to a remote receiver for control of valves and pumps for changing the water level in the pool. The receiver includes safety timers for filling and emptying to protect against equipment failure or communications faults. User selectable identification allows identical such radio systems to operate within proximity to each other. Power saving features are used to extend battery life.

Abstract: A single-sensor measurement system for detection and location of an AC signal emanating from a concealed energized electric conductor. A calibration routine of a measurement process carried out by the instrument first determines the background signal level of the AC signal at an initial position of the instrument. A second AC signal level is measured at a second location. The second signal level is compared with the background signal level. A signal indicating the presence of the energized electric conductor is generated by the instrument when the comparison result is greater than or equal to a predetermined value. The instrument initially positioned directly over a concealed energized electric conductor is automatically re-calibrated when a decrease in the AC signal level of a predetermined amount is detected. The electric field sensor is directly printed on the inside bottom panel of the instrument case and over the raised portions formed on the inside bottom panel.

Abstract: A device for locating the edges of wall studs includes a comparison circuit connected to each of three capacitive elements. As the device is moved along a wall, the comparison circuit monitors the relative charge time associated with each capacitive element, the charge times providing an indication of the relative capacitances of the three capacitive elements. Changes in the relative capacitances of the three elements as the device is moved along a wall are due to a change in the dielectric constant of the wall, which normally results from the presence of a wall stud behind the surface over which the device is moved. The comparison circuit uses differences in the measured relative capacitances of the first, second, and third capacitive elements to locate the edges of the stud.

Abstract: An impulse radar system useful, for instance, for ground penetration provides three dimensional images of targets. The radar system includes an antenna array with an arrangement of elements that is irregular so that the spacing between elements is different, thereby minimizing redundancy of path geometry between the array elements and the target. This feature reduces unwanted array sidelobes. The radar system incorporates circuitry which permits the utilization of each array element as either a transmitter or receiver antenna element. This dual utilization increases the effective number of elements in the antenna array, providing increased gain and system resolution. The radar system receiver utilizes multiple antenna array receiver elements, each of which is connected sequentially, through a solid state switch, to a single analog to digital converter, thereby providing a digitized signal for processing and display.

Abstract: A dual sensitivity stud sensor senses studs through both thick and thin surfaces. Studs are sensed by detecting a change in the capacitive loading of plates as they are moved along a surface and into proximity with a stud. The sensor informs the operator when the sensor has (incorrectly) been calibrated over a stud. The sensor also informs the operator if the sensor is placed against a surface either too thick or too thin for stud detection. Through use of a digital register, the sensor remains calibrated indefinitely while the sensor is powered on.

Abstract: An electronic level includes both a numeric scale and a graphic scale having a "fan-like" configuration of a number of elongated wedge-shaped segments. The inclination of the device is shown numerically using a digital display and, at cardinal angles, graphically by illuminating various segments on either side of a central segment line. The numeric scale provides a numeric indication of the angle of the level from 0.degree. to 360.degree. with respect to a null position, thus satisfying the need to measure absolute angles or slopes. The graphic display provides high resolution at cardinal angles while the numeric display provides lower resolution over 360.degree..

Abstract: A device for locating the edges of wall studs includes a comparison circuit connected to each of three capacitive elements. As the device is moved along a wall, the comparison circuit monitors the relative charge time associated with each capacitive element, the charge times providing an indication of the relative capacitances of the three capacitive elements. Changes in the relative capacitances of the three elements as the device is moved along a wall are due to a change in the dielectric constant of the wall, which normally results from the presence of a wall stud behind the surface over which the device is moved. The comparison circuit uses differences in the measured relative capacitances of the first, second, and third capacitive elements to locate the edges of the stud.

Abstract: A cost-effective wideband radar system capable of locating objects, such as reinforcing steel rods, pipes, and air bubbles, objects located behind or within a volume of, e.g., concrete, soil, wood, or air. A sequence of wideband radar pulses are emitted without a carrier from each of two transmit antennas. The system includes a receiver that detects reflected pulse energy (echoes) that result when transmitted pulses encounter a change in material (e.g., an air to metal change or concrete to metal change). These amplitudes of the echoes are visually displayed along with the length of the transmit/echo path for each transmitter. The lengths of the displayed transmit/echo paths are compared to determine whether the system is centered over an object located within or behind a volume, the system being centered over the object when the transmit/echo paths for each transmitter/receiver combination are of equal length.