Abstract: A MEMS device includes: a substrate as a base including a support portion and a detection electrode as a fixed electrode; a movable body supported to the support portion with a major surface of the movable body facing the fixed electrode; and an abutment portion facing at least a portion of an outer edge of the movable body and restricting rotational displacement in an in-plane direction of the major surface. The abutment portion includes an abutment surface including an abutment position at which the movable body abuts against the abutment portion due to the rotational displacement of the movable body, and a hollow portion provided opposing the abutment surface.

Abstract: A MEMS device includes: a substrate as a base including a support portion and a detection electrode as a fixed electrode; a movable body supported to the support portion with a major surface of the movable body facing the fixed electrode; and an abutment portion facing at least a portion of an outer edge of the movable body and restricting rotational displacement in an in-plane direction of the major surface. The abutment portion includes an abutment surface including an abutment position at which the movable body abuts against the abutment portion due to the rotational displacement of the movable body, and a hollow portion provided opposing the abutment surface.

Abstract: A capacitive micromechanical accelerometer comprising a first proof mass, a second proof mass, a third proof mass and a fourth proof mass. Each proof mass is configured as a seesaw which undergoes rotation out of the xy-plane in response to z-axis acceleration. The four proof masses are suspended from the same central anchor point with torsionally flexible suspension arrangements. Errors introduced into the output signal by wafer bending can be automatically compensated in a differential capacitive measurement.

Abstract: A physical quantity sensor includes a substrate, a movable section displaceable in a first direction with respect to the substrate, first and second movable electrode sections provided in the movable section, a first fixed electrode section fixed to the substrate and disposed to be opposed to the first movable electrode section in the first direction, a second fixed electrode section fixed to the substrate and disposed to be opposed to the second movable electrode section in the first direction, a restricting section configured to restrict a movable range in the first direction of the movable section, a first wire provided on the substrate and electrically connected to the first fixed electrode section, and a second wire provided on the substrate and electrically connected to the second fixed electrode section. The first wire and the second wire are respectively cross the restricting section in a plan view of the substrate.

Abstract: A method to create a multi-zone microstructure spring includes releasing a buckling layer from a substrate, wherein the buckling layer displaces into a curved shape after the releasing. The buckling layer is displaced, relative to the substrate, through at least one of a first zone, a second zone, and a third zone, wherein the buckling layer provides positive stiffness in the first zone, zero stiffness in a second zone, and negative stiffness in a third zone, and the buckling layer must pass through the first zone to reach the second zone and the buckling layer must pass through the second zone to reach the third zone. A multi-zone microstructure spring includes a substrate and a buckling layer. The buckling layer has a surface area. The buckling layer has a positive stiffness in a first zone, zero stiffness in a second zone, and a negative stiffness in a third zone.

Abstract: The invention relates to a sensor-type or actuator-type MEMS or NEMS device provided with a stacked stop element comprising —a first flat layer having a first flat electrode intended to be at a first electric potential and a second flat electrode intended to be at a second electric potential different from the first potential, said first flat electrode being movable relative to the second flat electrode in a first direction parallel to the first flat layer, —a second flat layer placed on top of the first flat layer and electrically insulated from the first flat layer by at least one intermediate layer made of an insulating material, the second flat layer comprising a first flat element that is mechanically secured to the first flat electrode, and a second flat element that is mechanically secured to the second flat electrode, characterized in that it further comprises at least one stop element extending from the first flat element or the second flat element in the first direction and projecting from said flat

Abstract: A physical quantity sensor includes: a base; wiring disposed in the base; a support that includes a first bonded surface bonded to the base and a second bonded surface bonded to the wiring; a suspension beam connected to the support; and an electrode finger supported by the suspension beam. The support is located between the first bonded surface and the suspension beam and includes a first overhang separated from the base.

Abstract: In accordance with embodiments of the present disclosure, an apparatus for measuring acceleration may include a spring-mounted mass, a positional encoder configured to measure a position of the spring-mounted mass and output one or more signals indicative of a sine and a cosine of the position, a driver to set and maintain an oscillation of the spring-mounted mass, and a decoder configured to process the one or more signals to calculate an acceleration of the spring-mounted mass.

Abstract: A composite sensor includes a first sensor outputting a first sensor signal, a second sensor outputting a second sensor signal, a circuit board electrically connected to the first and second sensors, and a mount member having one surface on which the first and second sensors and the circuit board are disposed. The first and second sensors have respective input terminals to which respective input signals are inputted, and have respective output terminals from which the first and second sensor signals are outputted. When a virtual straight line passing respective centers of the first and second sensors parallel to an arrangement direction of the sensors is defined, the respective input terminals of the first and second sensors are disposed in one of two regions divided by the virtual line, and the respective output terminals of the first and second sensors are disposed in a remaining one of the two regions.

Abstract: A physical quantity sensor has a first movable electrode section which has a portion facing a first fixed electrode section and a second movable electrode section which has a portion facing a second fixed electrode section, and is provided with a movable mass section which is formed in a shape which encloses a first fixed electrode side fixed section, a second fixed electrode side fixed section, a first movable electrode side fixed section, and a second movable electrode side fixed section in planar view.

Abstract: The present invention relates to A MEMS sensor with movable and fixed components for measuring linear acceleration. The MEMS sensor includes at least two mutually independent differential sensor elements disposed inside a common frame structure providing walls for hermetic sealing of the MEMS sensor. The mutually independent differential sensor elements are pairwise configured to perform double differential detection of linear acceleration. The MEMS sensor includes a common anchoring area to which the at least two differential sensor elements are anchored. The common anchoring area is located at the centroid of the pairwise configured differential sensor elements. A self-test capability of the MEMS sensor is also provided.

Abstract: A moving body tracking method and a moving body tracking device detect a position of a moving body in each of a plurality of frame images which configure a video, detect a trajectory of the moving body based on the image which is obtained by using the plurality of frame images, determine a final position of the moving body in each of the plurality of frame images based on the detected position and the position of the moving body which is obtained from the detected trajectory, and output the determined position.

Abstract: A MEMS trapped membrane. The MEMS trapped membrane includes a first layer and a second structure. The first layer has an outer section and an inner membrane. The outer section and inner membrane are detached from each other by a separation, and have inner membrane protrusions and outer section protrusions formed by the separation. The second structure is coupled to the outer section and has second protrusions that overlay corresponding inner membrane protrusions.

Abstract: A micro inertial measurement system includes a housing, a sensing module, and a damper. The sensing module includes a rigid sensing support, a measuring and controlling circuit board mounted on the rigid sensing support and an inertial sensor set on the measuring and controlling circuit board. The inertial sensor includes a gyroscope and an accelerometer. The sensing module is mounted in the housing. The damper is mounted in the housing and set in the gap between the sensing module and the inside wall of the housing. By use of the above-mentioned structure, the noise immunity of the inertial measuring system can be greatly improved, and the volume and weight of the inertial measuring system can be greatly reduced.

Abstract: Nanoelectromechanical logic devices can include a plurality of flexible bridges having control and logic electrodes. Voltages applied to control electrodes can be used to control flexing of the bridges. The logic electrodes can provide logical functions of the applied voltages.

Abstract: In various embodiments, a microelectromechanical system may include a chip, a substrate, a signal generator, and a fixing structure configured to fix the chip to the substrate. The chip may be fixed in such a way that, upon an acceleration of the microelectromechanical system, the chip is moved relative to the substrate. Furthermore, a signal may be generated by the movement of the chip by means of the signal generator.

Abstract: In an acceleration sensor having two redundantly disposed micromechanical sensor elements having redundant signal paths with a separate A/D converter, a monitor includes a substitute circuit, integrated in the evaluation unit, for a sensor element, and a redundant further A/D converter, which converts the fixed, acceleration-independent output signal of the substitute circuit as a function of the shared operating parameters of all A/D converters to plausibilize the output signals of the acceleration sensor by means of the monitor. This makes it possible to detect faulty triggering of an airbag due to faults in both A/D converters.

Abstract: A sensor includes a housing and a mass, suspended in the housing. The motion of the mass emulates dynamic behavior of a brain of the wearer along a plurality of axes. At least one sensing element is coupled to generate sensor data based on the motion of the mass, in response to an impact to a protective helmet.

Abstract: In a sensor module capable of changing a detection axis to detect a physical quantity, when a pad is provided at a location other than a corner point of an LSI-side, for the purpose of solving problems such as an increase in a chip surface area and an increase in development costs, caused by guide wiring for connecting the pad, the inertial sensor module is provided with: a first sensor element (100) having a first pad group (120), a second pad group (130) electrically connected to the first pad group and disposed at a location rotated 90 degrees with respect to the first pad group, and a detection axis; and an LSI (202) which controls the first sensor element. In the inertial sensor module, the first sensor element is disposed along a first side of the LSI, a plurality of third pad groups (203) is disposed along a second side intersecting the first side of the LSI, and the third pad group is electrically connected to either the first pad group or the second pad group.

Abstract: An impact detection device for detecting impacts to a body part of a user and various supporting systems are discussed. In an example, an impact detect device can include a circuit board, a component having a first section and a second section, a battery, and a molding for housing the circuit boat, the battery and the component. The circuit board can include impact detection circuitry including at least two sensors and a communication circuit. A zone of reduced rigidity can connect the first and second sections of the component, with the circuit board secured to the first section. The battery can be secured to the second section of the component allowing for flex relative to the circuit board. The molding can be shaped and dimensioned for mounting to a body part of the user.

Abstract: Disclosed herein is an acceleration sensor, including: a mass body part including a first mass body and a second mass body; a frame supporting the first mass body and the second mass body; first flexible parts each connecting the first mass body and the second mass body to the frame; and second flexible parts each connecting the first mass body and the second mass body to the frame, wherein the first mass body and the second mass body are each connected to the frame so as to be eccentric by the second flexible part.

Abstract: Disclosed herein is an apparatus for driving an inertial sensor, the apparatus including: at least one inertial sensor including a driving mass; an analog circuit unit detecting an amplitude value and a phase value of a driving mass resonance from a driving displacement signal of the inertial sensor; a first signal converting unit converting the amplitude value and the phase value into a digital value; a digital automatic gain control unit generating a control gain for controlling an amplitude or phase of the driving mass resonance so that the digitalized amplitude value or the phase value converges on a preset target value; and a second signal converting unit converting the control gain into an analog value and transmitting the analog value to the analog circuit unit, wherein the analog circuit unit applies a driving signal having the control gain reflected thereto to the inertial sensor.

Abstract: A fixed electrode part, a movable member supported by a support part above the fixed electrode part to which a principal surface thereof is opposed, and a stopper part provided to be opposed to at least a part of an outer edge of the movable member and regulating in-plane rotation displacement of the principal surface of the movable member are provided.

Abstract: An IV converter includes a first operational amplifier connected to the capacitive component, a second operational amplifier connected to the first operational amplifier, and an impedance element connected to the second operational amplifier. The first operational amplifier includes a first input terminal connected to the capacitive component, a second input terminal connected to a reference potential, and first and second output terminals. The first output terminal is connected to the first input terminal to constitute a feedback loop. The second operational amplifier includes a third input terminal connected to the second output terminal, a fourth input terminal connected to a reference potential, and a third output terminal connected to the third input terminal via the impedance element to constitute a feedback loop. The phases of the currents output by the first and second output terminals of the first operational amplifier are substantially identical to each other.

Abstract: A motion detection device specifies a movement of at least one of a subject and a sporting gear as an indicator of a trigger signal, using an output from an inertial sensor. The movement of at least one of the subject and the sporting gear is specified in the output from the inertial sensor. The trigger signal is generated according to the specified movement. The subject causes the trigger signal to be generated at proper timing through his or her own movement.

Abstract: A method of manufacturing an integrated circuit including a MEMS device includes forming a structural layer above a substrate including at least one semiconductor device. The method includes forming an attachment to a first portion of the structural layer, the attachment having a thickness substantially greater than a thickness of the structural layer. In at least one embodiment of the method, the attachment is conjoined with the first portion of the structural layer and the first portion of the structural layer and the attachment are operative to mechanically move in unison. In at least one embodiment of the method, forming the attachment includes forming a patterned filler layer of a first material above the structural layer and forming a patterned conformal layer of a second material on the patterned filler layer. The filler layer has a thickness substantially greater than the thickness of the structural layer.

Abstract: Systems and methods for perturbation analysis of harmonic oscillations in the time domain according to several embodiments can include a time domain switching sensor and a resonator for imposing a first oscillation and a second oscillation on the sensor. The first and second oscillations can have the same amplitude A and period P, but can have a known phase shift. The sensor can use a time interval, which can be defined by the time between when the sensor passes a reference point due to motion caused by the first oscillation and when the sensor passes the same reference point, but due to motion caused by the second oscillation. With this configuration an improved accuracy of measurement for the system can be realized.

Abstract: The present invention relates to a microelectromechanical structure, and more particularly, to systems, devices and methods of incorporating z-axis out-of-plane stoppers that are controlled to protect the structure from both mechanical shock and electrostatic disturbance. The z-axis out-of plane stoppers include shock stoppers and balance stoppers. The shock stoppers are arranged on a cap substrate that is used to package the structure. These shock stoppers are further aligned to a proof mass in the structure to reduce the impact of the mechanical shock. The balance stoppers are placed underneath the proof mass, and electrically coupled to a balance voltage, such that electrostatic force and torque imposed by the shock stoppers is balanced by that force and torque generated by the balance stoppers. This structure is less susceptible to mechanical shock, and shows a negligible offset that may be induced by electrostatic disturbance caused by the shock stoppers.

Abstract: A sensor system having a substrate and a mass which is movably suspended relative to the substrate is described, the sensor system including detection arrangement for detecting a deflection of the seismic mass relative to the substrate along a deflection direction, the detection arrangement including a first measuring electrode affixed to the substrate and a second measuring electrode affixed to the substrate, and a first overlap, which is perpendicular to the deflection direction, between the first measuring electrode and the seismic mass along the deflection direction is greater than a second overlap, which is perpendicular to the deflection direction, between the second measuring electrode and the seismic mass.

Abstract: A micro-electro mechanical apparatus with interdigitated spring including a substrate, at least one first mass, a movable electrode, a stationary electrode, an anchor and an interdigitated spring is provided. The movable electrode is disposed on the mass along an axial direction. The stationary electrode is disposed on the substrate along the axial direction, and the movable electrode and the stationary electrode have a critical gap there between. The interdigitated springs connects the mass and the anchor along the axial direction. The interdigitated spring includes first folded portions, first connecting portions, second folded portions, and second connecting portions. Each first folded portion includes two first spans and a first head portion. Each second folded portion includes two second spans and a second head portion. A width of the first span and a width of the second span are greater than the critical gap respectively.

Abstract: One embodiment of the invention includes an accelerometer sensor system. The system includes a sensor comprising a proofmass and electrodes and being configured to generate acceleration feedback signals based on control signals applied to the electrodes in response to an input acceleration. The system also includes an acceleration component configured to measure the input acceleration based on the acceleration feedback signals. The system further includes an acceleration controller configured to generate the control signals to define a first scale-factor range associated with the sensor and to define a second scale-factor range associated with the sensor. The control system includes a calibration component configured to calibrate the accelerometer sensor system with respect to range-dependent bias error based on a difference between the measured input acceleration at each of the first scale-factor range and the second scale-factor range.

Abstract: One embodiment of the invention includes an accelerometer sensor system. The system includes a sensor comprising a proofmass and electrodes and being configured to generate acceleration feedback signals based on control signals applied to the electrodes in response to an input acceleration. The system also includes an acceleration component configured to measure the input acceleration based on the acceleration feedback signals. The system further includes an acceleration controller configured to generate the control signals to define a first scale-factor range associated with the sensor and to define a second scale-factor range associated with the sensor. The control system includes a calibration component configured to calibrate the accelerometer sensor system with respect to range-dependent bias error based on a difference between the measured input acceleration at each of the first scale-factor range and the second scale-factor range.

Abstract: Disclosed herein is a MEMS apparatus comprising a substrate with an etched area, a proof mass disposed at the center of the etched area, and beams supporting the proof mass. The beams are disposed between peripheries of the substrate and the proof mass. The substrate comprises first and second electrodes that are parallel to an axis and extend respectively from opposite regions on the substrate. The proof mass comprises third and fourth electrodes that are parallel to the axis and extend respectively from opposite edges of the proof mass. The first and third electrodes are opposite to and interlaid with each other. The second and fourth electrodes are opposite to and interlaid with each other. With the proof mass constructed as an oxide layer optionally enclosing a connecting layer or as a silicon substrate optionally with a covering layer, the MEMS apparatus is not susceptible to the variation of temperature.

Abstract: To provide an acceleration sensor and a sensor network system having a construction in which the consumption of power to be consumed can be reduced and the sensor itself can be miniaturized without using any piezoelectric sensor or piezoelectric bimorph. An acceleration sensor device provided with an acceleration sensor which is an electrostatic induction conversion device for conversion between electric energy and kinetic energy, which comprises a conductor and an electret moving relatively to the conductor, said acceleration sensor device having: an acceleration detection unit to detect a signal corresponding to acceleration, from an AC voltage output by the acceleration sensor; a rectification unit to rectify the AC voltage; and a power supply circuit having a battery to power circuits in the device to work, to charge the battery with the rectified voltage as electric energy.

Abstract: A new class of accelerometer uses a differential Eddy current sensor to sense the displacement of the proof mass. This accelerometer can provide improved performance in an open-loop configuration based on the thermal stability and improved linearity of the differential Eddy current sensor. The accelerometer may provide lower cost alternatives to commercial grade accelerometers and lower cost and higher reliability alternatives to strategic grade accelerometers.

Abstract: The present invention relates to an apparatus and a method for automatic gain control of a sensor, and a sensor apparatus. The apparatus for automatic gain control of a sensor including: a PID control unit for outputting a gain value applied compensated sensor signal by performing PID control while generating and changing a gain value to converge a peak value of a sensor signal to a target value; and a margin calculation unit for determining the degree of change of peaks of a previous gain value applied compensated sensor signal and a current gain value applied compensated sensor signal and performing calculation of a margin for stabilizing the compensated sensor signal according to the result of determination of the degree of change is provided. Further, a sensor apparatus and a method for automatic gain control of a sensor are provided.

Abstract: An acceleration detector includes a base portion, a plate-like movable portion connected to the base portion via a joint portion, an acceleration detecting element laid over the base portion and the movable portion, and a supporting portion having a part extending along the movable portion from the base portion, as viewed in a plan view. A mass portion partly overlapping the supporting portion, as viewed in a plan view, is arranged on at least one of two main surfaces of the movable portion. The movable portion is displaceable about the joint portion as a fulcrum in a direction intersecting the main surface according to an acceleration applied in the direction intersecting the main surface. A space is provided between the mass portion and the supporting portion in an area where the mass portion and the supporting portion overlap each other.

Abstract: Acceleration sensor comprises vibrating element including piezoelectric body, circuit board amplifying output charge of the piezoelectric body that is generated due to bending vibration of the vibrating element, and sensor housing composed of highly conductive material, the sensor housing loading the vibrating element and the circuit board. The circuit board includes one or two extending region(s) formed so as to protrude from one side of the circuit board, the extending region(s) connecting mechanically and electrically the circuit board to the vibrating element. The sensor housing includes supporting base supporting the vibrating element, and recess portion is formed on the supporting base. The supporting base is configured such that the extending region(s) of the circuit board cover(s) the recess portion, and the vibrating element is fixed and supported by insulating adhesive agent with which space that is formed from the recess portion and the extending region(s) is filled.

Abstract: An acceleration sensor has a substrate, a seismic mass and a detection unit. The seismic mass is configured to be deflected based on an external acceleration acting on the acceleration sensor, the deflection being in the form of a deflection motion with respect to the substrate along a deflection direction. The detection unit is configured to be deflected for the detection of a deflection of the seismic mass, the detection being in the form of a detection motion with respect to the substrate along a detection direction. The detection unit is connected to the seismic mass in such a way that the amplitude of the deflection motion along the deflection direction is greater than the amplitude of the detection motion along the detection direction.

Abstract: A method for producing microelectromechanical structures in a substrate includes: arranging at least one metal-plated layer on a main surface of the substrate in a structure pattern; leaving substrate webs open beneath a structure pattern region by introducing first trenches into the substrate perpendicular to a surface normal of the main surface in a region surrounding the structure pattern; coating the walls of the first trenches perpendicular to the surface normal of the main surface with a passivation layer; and introducing cavity structures into the substrate at the base of the first trenches in a region beneath the structure pattern region.

Abstract: This document discusses, among other things, an mode matching circuit for a inertial sensor including an oscillator circuit configured to selectively couple to a sense axis of an inertial sensor and to provide sense frequency information of the sense axis, a frequency comparator configured to receive the sense frequency information of the sense axis and drive frequency information of the inertial sensor, and to provide frequency difference information to a processor, and a programmable bias source configured to apply a bias voltage to the sense axis to set a sense frequency of the sense axis in response to a command from the processor, and to maintain a desired frequency difference between the sense frequency and a drive frequency of the inertial sensor.

Abstract: An acceleration sensor having a substrate, at least one web, and a seismic mass, the web and the seismic mass being situated over a plane of the substrate. The seismic mass is situated on at least two sides of the web and elastically suspended on the web. The web is anchored on the substrate with the aid of at least one anchor. At least one anchor is situated outside the center of gravity of the seismic mass.

Abstract: Disclosed herein are an inertial sensor and a method of manufacturing the same. The inertial sensor includes: a flexible part; a mass body movably supported by the flexible part and including a metal; a post supporting the flexible part; piezoelectric elements driving the mass body or sensing displacement of the mass body; and a package enclosing the flexible part, the mass body, and the post, wherein the metal has a melting point lower than the Curie temperature of the piezoelectric elements and higher than that of a solder forming connection parts for a surface mounting technology (SMT) provided on the package.

Abstract: An acceleration sensor is provided. The acceleration sensor contains a first electrically conductive element and a second electrically conductive element. An electrically insulative element is connected to the first electrically conductive element and the second electrically conductive element, where at least a portion of the first electrically conductive element and at least a portion of the second electrically conductive element make contact with the electrically insulative element. At least one electrically conductive spring is located within a cavity of the sensor, wherein the cavity is defined by at least one surface of the first electrically conductive element, at least one surface of the electrically insulative element, and at least one surface of the second electrically conductive element.

Abstract: Disclosed herein is a driving control module for an inertial force. The driving control module includes a timing control unit that applies a driving signal and a sensing signal; a driving unit that receives the driving signal from the timing control unit and applies the driving signal to a sensor; a sensing unit that receives the sensing signal from the timing control unit, applies the sensing signal to a sensor, and senses stabilization driving and inertial force of the sensor; and a driving control unit that locks application of the driving signal from the timing control unit to the driving unit.

Abstract: A servo system is provided for controlling movement of a flexible structure having multiple masses and elements. Each element couples a respective two of the masses and functions as a spring when the flexible structure is subject to a linear or rotational input at or above a frequency at which the respective element exhibits flexure. The servo system includes multiple sensors, where each sensor is disposed relative to a respective one of the masses to sense a respective acceleration. A motor having a torque input may operatively be configured to output one of a linear or rotational force on the first mass based on a torque signal present on the torque input. A servo controller that receives each sensed acceleration from each sensor may generate a compensation feedback signal based on a sum of sensed accelerations. The torque signal may be output to the motor based on the compensation feedback signal.

Abstract: In various embodiments, a microelectromechanical system may include a chip, a substrate, a signal generator, and a fixing structure configured to fix the chip to the substrate. The chip may be fixed in such a way that, upon an acceleration of the microelectromechanical system, the chip is moved relative to the substrate. Furthermore, a signal may be generated by the movement of the chip by means of the signal generator.

Abstract: An acceleration sensor includes a housing, a first seismic mass which is formed as a first asymmetrical rocker and is disposed in the housing via at least one first spring, a second seismic mass which is formed as a second asymmetrical rocker and is disposed in the housing via at least one second spring, and a sensor and evaluation unit which is designed to ascertain information regarding corresponding rotational movements of the first seismic mass and the second seismic mass in relation to the housing and to determine acceleration information with respect to an acceleration of the acceleration sensor, taking the ascertained information into account. In addition, a method for operating an acceleration sensor is disclosed. The rockers execute opposite rotational movements in response to the presence of an acceleration. A differential evaluation of the signals makes it possible to free the measuring signal of any existing interference signals.

Abstract: An inertial force sensor includes a detecting device which detects an inertial force, the detecting device having a first orthogonal arm and a supporting portion, the first orthogonal arm having a first arm and a second arm fixed in a substantially orthogonal direction, and the supporting portion supporting the first arm. The second arm has a folding portion. In this configuration, there is provided a small inertial force sensor which realizes detection of a plurality of different inertial forces and detection of inertial forces of a plurality of detection axes.

Abstract: An apparatus having an arrangement of two or more identical accelerometers with aligned sensitivity axes. Each of the accelerometers senses motion over at least one axis. The accelerometer readings include a component corresponding to gravitational force that is the same for each accelerometer in the arrangement. Logic circuitry in communication with the accelerometer arrangement couples accelerometer signals to a processor to compute motion variables.