Various embodiments provide systems and methods capable of facilitating interaction with handheld electronics devices based on sensing rotational rate around at least three axes and linear acceleration along at least three axes. In one aspect, a handheld electronic device includes a subsystem providing display capability, a set of motion sensors sensing rotational rate around at least three axes and linear acceleration along at least three axes, and a subsystem which, based on motion data derived from at least one of the motion sensors, is capable of facilitating interaction with the device.

Controlling and accessing content using motion processing on mobile devices

The monitoring of acceleration is essential for a variety of applications ranging from inertial navigation to consumer electronics. Typical accelerometer operation involves the sensitive displacement measurement of a flexibly mounted test mass, which can be realized using capacitive, piezo-electric, tunnel-current or optical methods. Although optical detection provides superior displacement resolution, resilience to electromagnetic interference and long-range readout, current optical accelerometers either do not allow for chip-scale integration or utilize relatively bulky test mass sensors of low bandwidth. Here, we demonstrate an optomechanical accelerometer that makes use of ultrasensitive displacement readout using a photonic-crystal nanocavity monolithically integrated with a nanotethered test mass of high mechanical Q-factor This device achieves an acceleration resolution of 10 µg Hz^(−1/2) with submilliwatt optical power, bandwidth greater than 20 kHz and a dynamic range of greater than 40 dB. Moreover, the nanogram test masses used here allow for strong optomechanical backaction, setting the stage for a new class of motional sensors.

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A high-resolution microchip optomechanical accelerometer

Colloidal lithography is a recently emerging field; the evolution of this simple technique is still in progress. Recent advances in this area have developed a variety of practical routes of colloidal lithography, which have great potential to replace, at least partially, complex and high-cost advanced lithographic techniques. This Review presents the state of the art of colloidal lithography and consists of three main parts, beginning with synthetic routes to monodisperse colloids and their self-assembly with low defect concentrations, which are used as lithographic masks. Then, we will introduce the modification of the colloidal masks using reactive ion etching (RIE), which produces a variety of nanoscopic features and multifaceted particles. Finally, a few prospective applications of colloidal lithography will be discussed.

Nanomachining by colloidal lithography

Focused ion beam (FIB) technology has become increasingly popular in the fabrication of nanoscale structures. In this paper, the recent developments of the FIB technology are examined with emphasis on its ability to fabricate a wide variety of nanostructures. FIB-based nanofabrication involves four major approaches: milling, implantation, ion-induced deposition, and ion-assisted etching of materials; all these approaches are reviewed separately. Following an introduction of the uniqueness and strength of the technology, the ion source and systems used for FIB are presented. The principle and specific techniques underlying each of the four approaches are subsequently studied with emphasis on their abilities of writing structures with nanoscale accuracy. The differences and uniqueness among these techniques are also discussed. Finally, concluding remarks are provided where the strength and weakness of the techniques studied are summarized and the scopes for technological improvement and future research are recommended.

Recent Developments in Nanofabrication Using Focused Ion Beams

A home entertainment system for video games and other applications includes a main unit and handheld controllers. The handheld controllers sense their own motion by detecting illumination emitted by emitters positioned at either side of a display. The controllers can be plugged into expansion units that customize the overall control interface for particular applications including but not limited to legacy video games.

Video game system with wireless modular handheld controller

Fundamentals of Micromachined Vibratory Gyroscopes.- Fundamentals of Micromachined Gyroscopes.- Fabrication Technologies.- Mechanical Design of MEMS Gyroscopes.- Electrical Design of MEMS Gyroscopes.- Structural Approaches to Improve Robustness.- Linear Multi DOF Architecture.- Torsional Multi DOF Architecture.- Distributed Mass Architecture.- Conclusions and Future Trends.

MEMS Vibratory Gyroscopes: Structural Approaches to Improve Robustness

This paper reports the experimental analysis of commercially available variable-capacitance MEMS accelerometers, characterized under standardized tests. Capacitive MEMS sensors of the same low-level input acceleration range with various mechanical sensing element designs, materials, fabrication technologies and price ranges were selected for evaluation. The selected sensors were characterized using ANSI and NIST certified testing equipment and under the same testing conditions; and their sensitivity, resolution, linearity, frequency response, transverse sensitivity, temperature response, noise level and long-term stability were tested and compared. The experimental results are then interpreted to provide an insight to advantages and disadvantages for using a particular mechanical design, fabrication technology, sensor material and the techniques for electronics integration and packaging of each specific sensor design.

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Experimental evaluation and comparative analysis of commercial variable-capacitance MEMS accelerometers

This paper reports a novel four-degrees-of-freedom (DOF) nonresonant micromachined gyroscope design concept that addresses two major MEMS gyroscope design challenges: eliminating the mode-matching requirement and minimizing instability and drift due to mechanical coupling between the drive and sense modes. The proposed approach is based on utilizing dynamical amplification both in the 2-DOF drive-direction oscillator and the 2-DOF sense-direction oscillator, which are structurally decoupled, to achieve large oscillation amplitudes without resonance. The overall 4-DOF dynamical system is composed of three proof masses, where second and third masses form the 2-DOF sense-direction oscillator, and the first mass and the combination of the second and third masses form the 2-DOF drive-direction oscillator. The frequency responses of the drive and sense direction oscillators have two resonant peaks and a flat region between the peaks. The device is nominally operated in the flat regions of the response curves belonging to the drive and sense direction oscillators, where the gain is less sensitive to frequency fluctuations. This is achieved by designing the drive and sense anti-resonance frequencies to match. Consequently, by utilizing dynamical amplification in the decoupled 2-DOF oscillators, increased bandwidth and reduced sensitivity to structural and thermal parameter fluctuations and damping changes are achieved, leading to improved robustness and long-term stability over the operating time of the device.

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Nonresonant micromachined gyroscopes with structural mode-decoupling

The limitations of the photolithography-based micromachining technologies defines the upper-bound on the performance and robustness of micromachined gyroscopes. Conventional gyroscope designs based on matching (or near-matching) the drive and sense modes are extremely sensitive to variations in oscillatory system parameters that shift the natural frequencies and introduce quadrature errors. Nonconventional design concepts have been reported that increase bandwidth to improve robustness, but with the expense of response gain reduction. This paper presents a new approach that may yield robust vibratory MEMS gyroscopes with better gain characteristics while retaining the wide bandwidth. The approach is based on utilizing multiple drive-mode oscillators with incrementally spaced resonance frequencies to achieve wide-bandwidth response in the drive-mode, leading to improved robustness to structural and thermal parameter fluctuations. Enhanced mode-decoupling is achieved by distributing the linear drive-mode oscillators radially and symmetrically, to form a multidirectional linear drive-mode and a torsional sense-mode; minimizing quadrature error and zero-rate output. The approach has been implemented on bulk-micromachined prototypes fabricated in a silicon-on-insulator (SOI)-based process, and experimentally demonstrated.

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An approach for increasing drive-mode bandwidth of MEMS vibratory gyroscopes

This paper reports a novel gimbal-type torsional micromachined gyroscope with a non-resonant actuation scheme. The design concept is based on employing a 2 degrees-of-freedom (2-DOF) drive-mode oscillator comprising a sensing plate suspended inside two gimbals. By utilizing dynamic amplification of torsional oscillations in the drive mode instead of resonance, large oscillation amplitudes of the sensing element are achieved with small actuation amplitudes, providing improved linearity and stability despite parallel-plate actuation. The device operates at resonance in the sense direction for improved sensitivity, while the drive direction amplitude is inherently constant within the same frequency band. Thus, the necessity to match drive and sense resonance modes is eliminated, leading to improved robustness against structural and thermal parameter fluctuations. In the paper, the structure, operation principle and a MEMS implementation of the design concept are presented. Detailed analysis of the mechanics and dynamics of the torsional system is covered, and the preliminary experimental results verifying the basic operational principles of the design concept are reported.

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Cenk Acar

Papers

MEMS Vibratory Gyroscopes: Structural Approaches to Improve Robustness

Experimental evaluation and comparative analysis of commercial variable-capacitance MEMS accelerometers

Nonresonant micromachined gyroscopes with structural mode-decoupling

An approach for increasing drive-mode bandwidth of MEMS vibratory gyroscopes

Structural design and experimental characterization of torsional micromachined gyroscopes with non-resonant drive mode