Abstract: Systems and methods are provided for calibrating electromagnetic position tracking systems commonly used in virtual reality systems by compensating for steady state magnetic field distortions that can occur within a tracking volume and distort magnetic sensor readings. The calibration system includes a calibration device that holds magnetic sensor(s) in a fixed position relative to a reference position sensor object provided on the calibration device. The calibration data collection process includes positioning the calibration device at multiple locations within a tracking volume and measuring magnetic position readings using a magnetic tracking system and a corresponding reference position using the reference position tracking system.

Abstract: Systems and methods are provided for calibrating electromagnetic position tracking systems commonly used in virtual reality systems by compensating for steady state magnetic field distortions that can occur within a tracking volume and distort magnetic sensor readings. The calibration system includes a calibration device that holds magnetic sensor(s) in a fixed position relative to a reference position sensor object provided on the calibration device. The calibration data collection process includes positioning the calibration device at multiple locations within a tracking volume and measuring magnetic position readings using a magnetic tracking system and a corresponding reference position using the reference position tracking system.

Abstract: A flexible transmitter light bar and a flexible receiver light bar may be used, in conjunction with a controller, to prevent or reverse closure of a door, such as an elevator door, when an object blocks the transmission of light from the transmitter light bar to the receiver light bar. By using flexible light bars, shipping costs, storage footprints and installation efforts are significantly reduced as compared to rigid light bars currently in use. The light bars may be applied with an adhesive and may further include one or more mounting holes. The light bars may be sealed to be water proof and permit easy cleaning thereof. The light bars may be useful in retrofit applications as well as in newly installed doors.

Abstract: An apparatus and method for detection of uplink frequencies from a mobile device, such as a cell phone, may be used as an alarm for people not to use their mobile device, or may signal security personnel when an unauthorized mobile device is being used. The apparatus and method may measure the uplink frequency band and use feedback with the downlink frequencies to gain a better reading of the distance the mobile device being used is from the detection device The apparatus and method has more precision of distance compared to conventional detectors, as the uplink RF power of a mobile device changes depending where it's located from the cell tower transmitting the downlink data to the mobile device monitored.

Abstract: High efficiency drive circuitry for a group of parallel-connected light emitting devices, in which each device is driven in series by a respective source of bias current. The maximum voltage drop among the group of biased light emitting devices is determined and in response, a control voltage to drive all the light emitting device at the lowest effective voltage for the LED group is produced.

Abstract: An apparatus and method for detection of uplink frequencies from a mobile device, such as a cell phone, may be used as an alarm for people not to use their mobile device, or may signal security personnel when an unauthorized mobile device is being used. The apparatus and method may measure the uplink frequency band and use feedback with the downlink frequencies to gain a better reading of the distance the mobile device being used is from the detection device The apparatus and method has more precision of distance compared to conventional detectors, as the uplink RF power of a mobile device changes depending where it's located from the cell tower transmitting the downlink data to the mobile device monitored.

Abstract: An apparatus and method for a portable device incorporating a battery and a battery charger. In the portable device, there are a plurality of system components configured to facilitate a plurality of functions that the portable device is designed to perform. The battery in the portable device is configured for providing an internal power supply to the plurality of system components in the absence of an external input power supply. The battery charger is configured for charging the battery when the external input power supply is available. The battery charger disclosed herein is capable of supplying system power to the system components when voltage of the battery that is being charged is below a limit, thereby allowing the portable device to operate when voltage of the battery drops below the limit.

Abstract: An apparatus and method for a portable device incorporating a battery and a battery charger. In the portable device, there are a plurality of system components configured to facilitate a plurality of functions that the portable device is designed to perform. The battery in the portable device is configured for providing an internal power supply to the plurality of system components in the absence of an external input power supply. The battery charger is configured for charging the battery when the external input power supply is available. The battery charger disclosed herein is capable of supplying system power to the system components when voltage of the battery that is being charged is below a limit, thereby allowing the portable device to operate when voltage of the battery drops below the limit.

Abstract: A switching circuit for converting an input voltage into an output voltage has an input terminal for receiving the input voltage. A power switching element is coupled to the input terminal and has duty cycle d controllable to adjust the output voltage with respect to a desired level using inductor current representing current in an inductor element connectable to the power switching element. An average and hold circuit is responsive to a voltage at an output of the power switching element to produce an average switch voltage over an ON phase of a switching cycle of the power switching element. A voltage-to-current converter is responsive to the average switch voltage for producing representation of an average inductor current over one or more switching cycles. A current modulator having a duty cycle equal to 1-d modulates the representation of the average inductor current to produce a signal proportional to an average output current of the switching circuit over one or more switching cycles.

Abstract: A switching circuit coupled to one or more input sources and having one or more switching elements controlled to produce an output for charging a battery. A first control circuit is responsive to current of the switching circuit for producing a first control signal to drive the switching element so as to control the current. A second control circuit is responsive to voltage at the battery for producing a second control signal to drive the switching element so as to control voltage developed across the battery. A selector circuit is responsive to the first and second control signals for selectively controlling the switching element.

Abstract: A switching circuit for converting an input voltage into an output voltage has an input terminal for receiving the input voltage. A power switching element is coupled to the input terminal and has duty cycle d controllable to adjust the output voltage with respect to a desired level using inductor current representing current in an inductor element connectable to the power switching element. An average and hold circuit is responsive to a voltage at an output of the power switching element to produce an average switch voltage over an ON phase of a switching cycle of the power switching element. A voltage-to-current converter is responsive to the average switch voltage for producing representation of an average inductor current over one or more switching cycles. A current modulator having a duty cycle equal to 1-d modulates the representation of the average inductor current to produce a signal proportional to an average output current of the switching circuit over one or more switching cycles.

Abstract: A pallet and an associated method are provided for supporting an item mounted upon casters. The pallet includes a pallet deck having a fixed portion and a movable portion. The movable portion moves between a first position in which the movable portion is displaced, such as by being rotated downwardly, from the fixed portion and a second position in which the movable and fixed portions cooperate to define a support surface. The movable portion is in the second position while the item is loaded, but is moved to the first position during shipment. The pallet also includes a support for supporting the item once the movable portion is in the first position. Prior thereto, however, the item is typically spaced from the support. Each support can include a stationary portion and a movable portion that moves between a retracted position to facilitate loading and an extended position during shipment.

Abstract: A pallet and an associated method are provided for supporting an item mounted upon casters. The pallet includes a pallet deck having a fixed portion and a movable portion. The movable portion moves between a first position in which the movable portion is displaced, such as by being rotated downwardly, from the fixed portion and a second position in which the movable and fixed portions cooperate to define a support surface. The movable portion is in the second position while the item is loaded, but is moved to the first position during shipment. The pallet also includes a support for supporting the item once the movable portion is in the first position. Prior thereto, however, the item is typically spaced from the support. Each support can include a stationary portion and a movable portion that moves between a retracted position to facilitate loading and an extended position during shipment.

Abstract: A pallet and an associated method are provided for supporting an item mounted upon casters. The pallet includes a pallet deck having a fixed portion and a movable portion. The movable portion moves between a first position in which the movable portion is displaced, such as by being rotated downwardly, from the fixed portion and a second position in which the movable and fixed portions cooperate to define a support surface. The movable portion is in the second position while the item is loaded, but is moved to the first position during shipment. The pallet also includes a support for supporting the item once the movable portion is in the first position. Prior thereto, however, the item is typically spaced from the support. Each support can include a stationary portion and a movable portion that moves between a retracted position to facilitate loading and an extended position during shipment.

Abstract: A radiation-sensitive composition especially adapted to prepare a lithographic printing plate that is sensitive to both ultraviolet and infrared radiation and capable of functioning in either a positive-working or negative-working manner is comprised of (1) a resole resin, (2) a novolac resin, (3) a haloalkyl-substituted s-triazine and (4) an infrared absorber. The solubility of the composition in aqueous alkaline developing solution is both reduced in exposed areas and increased in unexposed areas by the steps of imagewise exposure to activating radiation and heating.