Abstract: A combination radar/laser detector with environmental sensors is programmed to provide a range of functions, including weather information, road conditions and the like, and in some cases to incorporate road-specific information in functionality. The road-specific information may be provided by roadside RF broadcast terminals. In a preferred embodiment the system monitors characteristics that indicate a driver's state of awareness, and audio alerts are provides when the system determines a driver is dozing or drifting toward a dozing state. In various embodiments a broad range of functionality is provided based on received and sensed parameters.

Abstract: A multi-function electronic compass incorporates multiple sensors in addition to magnetometers inputting sensed data to a microprocessor system which calculates a variety of results from the sensed data in addition to direction. Direction indicia and other results are output for a user on a display. Additional sensors include one or more of an inclinometer, an altimeter, an accelerometer, and a barometer. In one aspect the compass has a tilt-up lid with a sighting port and an adjacent mirror, and the microprocessor system displays directional indicia backwards so the reflected indicia in the mirror adjacent to the sighting port are directly readable by the user using the sighting port. In one model a laser beam is included as an aid in sighting.

Abstract: A magnetic field sensor element comprises an elongated core of high-magnetic permeability material having a coil of electrically-conductive wire wound around and along a central axis of the core. The sensor, due to inductance of the core which changes with application of a local magnetic field, exhibits a characteristic of delaying an electrical input as a function of the strength of a magnetic field in the direction of the axis of the core, and the delay is measured as a function of the strength of the magnetic field. Appropriate circuitry provides at least one step-function voltage input to the coil such that the resulting delay in current charge-up into the coil creates a voltage across the coil which decays to a known reference value. The time delay for the voltage decaying to the reference value varies as a monotonic function with the strength of the applied magnetic field to be measured.

Abstract: A new tilt sensor system is disclosed which provides substantial temperature independence and is very inexpensive to build and to operate. The apparatus is made up of a first source of a first alternating signal having an output impedance Rs1 and a second source of a second alternating signal which is equal in magnitude and 180 degrees out of phase with the first alternating signal, with the source of the second alternating signal having an output impedance Rs2. Also included is a tilt sensor having a first input terminal coupled to receive the first alternating signal, a second input terminal coupled to receive the second alternating signal, and an output terminal which provides an output signal in response to the first alternating signal and the second alternating signal. In the preferred mode, the tilt sensor has an impedance G1 between the first terminal and the output terminal and an impedance G2 between the second terminal and the output terminal.

Abstract: Measurement circuitry for a biaxial inclinometer having electrolytic fluid incorporates a Schmitt trigger for measuring the resistance of each leg of the inclinometer by measuring the frequency output of the Schmitt trigger circuit while each leg is placed across input and output terminals. Switching is accomplished by cycling analog multiplexers as solid-state switches under control of a microprocessor. To minimize net dc current across any leg, legs are periodically reversed in polarity as they are switched into the Schmitt trigger circuit for measurement. Additionally, in the wiring of the switching multiplexers to the inclinometer legs, an additional analog multiplexer is switched to place a low clamp resistance in parallel with each leg not being measured in a cycle, to compensate for leakage current.

Abstract: An electronic compass has a display including a reference pointer that indicates a reference heading stored in response to an input signal. The reference heading is the current heading at the time of the input signal, and the reference pointer in the display is updated as the orientation of the compass changes.

Abstract: A magnetometer technology is provided based on a simple axial sensor which operates using the non-linear nature of saturating magnetic core material. The sensor appears electrically as an inductor with a non-linear inductance that varies both with magnetic field applied externally and the field created by the coil current. By using this sensor as the inductor of an LR relaxation oscillator, a change in applied magnetic field will cause a change in inductance, which will in turn cause a change in the oscillator period. The period of the oscillator can be converted to a digital form by using simple counting techniques. By introducing an enhancement of this scheme whereby two different periods are measured with different oscillator characteristics, the magnetometer will have no output drift when no field is applied.