An acceleration sensor comprises a mass, which can be deflected in a first direction and a second direction opposite to the first direction, a driver effective to vibrate the mass, a detector for detecting times when the mass passes a predetermined position when an acceleration is applied, and an evaluator which detects the acceleration based on the detected times during acceleration and times when the mass passes the predetermined position when no acceleration is applied. Thereby, it is achieve...

Systems, methods and circuits for implementing a self test in a slowly varying sensor. In one particular case, a circuit is provided that includes two filters operating in parallel. One of the filters is tailored for filtering normal operational signals, and operates at a first oversampling rate. The other filter is tailored for filtering test signals, and operates at a second oversampling rate. The second oversampling rate is generally less than the first oversampling rate. In various cases, th...

The present invention is directed to an acoustic vector sensor, also called particle velocity sensor. <111> direction poled, shear mode, relaxor single crystals are used as the sensing elements. In addition, these crystal plates are cut at a special orientation such that they provide zero or minimum responses in the transverse directions, but have a maximum piezoelectric response in sensing direction. The piezoelectric sensor contains a proof mass, a base, and an aforementioned relaxor cry...

Quadrature suppression is provided by placing a resonator mass adjacent to a quadrature suppression electrode. The resonator mass is capable of moving substantially parallel to the quadrature suppression electrode and includes a notch formed adjacent to a portion of the quadrature suppression electrode such that a length of resonator mass that is directly adjacent to the quadrature suppression electrode varies as the resonator mass moves relative to the quadrature suppression electrode. The quad...

Methods and systems are disclosed for determining speed, power and/or impact (sporting characteristics) of persons involved in activity. Wireless signals may be generated indicative of the sporting characteristics for receipt and display on a watch worn by the user or on a remote display. Sensors may attach to the person or to a vehicle ridden by the person, to gauge activities such as jogging, hockey, biking, football and aerobics.

An acceleration sensor capable of standing a great acceleration is to be provided. It is configured of a mounting board and a sensor chip in which the sensor chip is formed of a weight, a beam and a frame. Then, the weight is surrounded by the frame. The weight is joined to the frame by a plurality of the beams, and the weight is separated from the board by being supported by the beams. Additionally, a thin, rectangular stopper is disposed on the mounting board right under the weight.

An angular velocity sensor device includes a switch (S1) for selecting a first or second driving signal mutually opposite in phase applied to driving electrodes (D1, D2) to oscillate a weight part (8) in a first direction. An adding circuit (29) adjusts the amplitude of the driving signal selected and adds it to a monitor signal reflecting the oscillating state of the weight part (8). A noise signal component appearing in the output signal of the adding circuit (29) is adjusted to a minimum and ...

This invention is an apparatus and method for determining the velocity of a projectile. A light curtain unit (20) creates two light curtains (46)(48) and two sensing planes (50)(52). The projectile causes light from the light curtain (46)(48) to be reflected into the detectors (22a) and (24a) of the sensing planes (50)(52). The time for a projectile to pass through one sensing plane to the other is measured and calculated for display by the Display Unit (10).

A measurement apparatus includes a speed sensor, a cadence sensor and a display portion. The apparatus further includes a transmit portion for wirelessly transmitting signals detected by the speed sensor and the cadence sensor to the display portion. The transmit portion is provided with a shaft portion extending in one direction, which rotatably supports the cadence sensor and the speed sensor. A measurement body portion including the speed sensor, the cadence sensor and the transmit portion is...

An acceleration sensor is formed on a top surface of a laminated silicon-on-insulator substrate. The acceleration sensor is composed of first and second capacitors each including a movable electrode that moves according to acceleration imposed thereon. The first and the second capacitors are so made that their capacitances change differently when the same acceleration is imposed and that the capacitance difference represents an amount of acceleration imposed thereon. A third capacitor having an ...