MEMS Tilt Sensor Research Articles

Hybrid Approach for Identification of Manhole and Staircase Using Image Processing

The main aim of this research paper is to provide multi security for the pedestrians/older using smart stick using IOT and GPS. This stick having IOT, voice module and attached with multiple sensors to provide high security to the blind peoples while walking. Now a day’s safety is main important cause to the peoples while walking or driving and many more places. This smart stick provides the high security and show way to walk, by using this system we can monitor the blind person position using web application/mobile application and also we can get emergency alert message along with exact location. This system has obstacle sensor, water sensor and MEMS sensors, so that it can detect obstacles sizes automatically and gives voice alert. By using water sensors, it can detect the floor condition is dry or wet and shows the way to walk. In case of any emergency person suddenly fall at floor/any place then this system immediately detects using MEMS tilt sensor and automatically send the message to respective numbers with location and also gives buzzer alarm continuously to alert the neighbours. So that this smart stick can be very useful to peoples to show correct path while walking on the floor or steps and many more places. In this paper, the system can be interconnected with the microcontroller and alert the respective persons when any emergency occurs. This tracking system is composed of a GPS receiver, Microcontroller. The Microcontroller processes this information and this processed information is sent to the respective numbers using web page.

A Novel Single-Axis MEMS Tilt Sensor with a High Sensitivity in the Measurement Range from 0∘ to 360∘.

In this paper, a novel single-axis MEMS tilt sensor is presented. It contains a hexagonal proof mass, six micro-lever force amplifiers and three double-ended-tuning fork (DETF) resonant strain gauges. The proof mass is placed in the center with the micro-levers and the DETFs radially arrayed around. The variation of gravity acceleration applied on the proof mass will result in frequency shifts of the DETFs. Angular tilt can be got by analyzing the frequency outputs. The structural design of the tilt sensor is optimized by finite element simulation and the device is microfabricated using a silicon-on-insulator process, followed by open-loop and closed-loop characterizations. Results show that the scale factor of such sensor is at least 11.53 Hz/degree. Minimum Allan deviation of the DETF oscillator is 220 ppb (parts per billion) of the resonant frequency for an 5 s integration time. Resolution of the tilt sensor is in the whole measurement range from to .

A MEMS tilt sensor with expanded operating range and improved sensitivity

In this paper, a simple and novel method of expanding the operating range of inclinations and of increasing the sensitivity of convection-based tilt sensors is shown. Even though the previously reported convective tilt sensors fabricated in our laboratory have their own merits in performing dual-axes inclination measurement with excellent linearity and symmetric sensitivity, they showed limited operating range from −90 to 90° because of their structural limitations. However, this proposed tilt sensor has overcome the structural limitations and it detects inclinations wider than the ±90° range on two axes with symmetric sensitivity. The improved performance could be achieved by removing the membrane at the bottom of the microheater and temperature sensors for unlimited gas movement in the cavity when it tilted over the ±90° range. The operating range of the newly proposed tilt sensor expands to ±180° compared with that of the previously reported convective tilt sensor. Moreover, various designs of cavities and cap substrates were adopted to improve the sensitivity of the proposed convective tilt sensor. The mass production of the proposed convection-based tilt sensor is still feasible because it can be fabricated at a low cost because of its simple fabrication step. Its sensitivity is high and it has a very wide-angle detection range.

A Self-Calibrating Mathematical Model for the Direct Piezoelectric Effect of a New MEMS Tilt Sensor

This paper presents a self-calibrating mathematical model and simulation results of the direct piezoelectric effect of a new tilt-sensor that measures inclination angles around two orthogonal axes. Using a fundamental description of the mechanical stress generated in suspended beams under static loading, we propose a model of the sensor's direct piezoelectric effect that is only a trigonometric function of its genetic behavior in two orthogonal planes. The significance of the proposed approach lies in the independence of the model from the structural dimensions of the piezo-system and the electro-mechanical properties of the piezoelectric layer. The effect of these structural properties and other external stimuli on the proposed model is implicitly contained, and inherently carried by the genetic data which is curve-fitted using a polynomial approximation. The feasibility of the proposed method and the accuracy of the model are verified by cross-comparison with simulation results. These simulations are performed on a CAD model of the piezoelectric tilt sensor for a case-study operation range of 0 - 90° . An overall considerable accuracy level was noted between the simulated and modeled data over the full operation range, with an average relative peak error of 1.9%.

MEMS Gyro Aided Calibration of Electronic Compass

In this paper, an MEMS gyro aided on line calibration algorithm for electronic compass is presented. This electronic compass module consists of a three-axis AMR sensor, a two-axis MEMS tilt sensor and a one-axis MEMS gyro. The automatic calibration method requires to rotate the electronic compass two full 360-degree revolution. In this rotation procedure, magnetic field data, attitude data and angular rate data are recorded. Based on recorded magnetic field data and attitude data, raw heading data is calculated. This raw heading data is verified by angular rate output of MEMS gyro. Results of experiment show that the accuracy of calibrated compass is better than 0.5 deg and MEMS gyro aided on line calibration algorithm is effective for electronic compass.

MEMS Tilt Sensor Fabricated Utilizing Anodic Bonding of Thin Silicon Film on Glass Substrate

This paper reports on a new type of a tilt sensor fabricated using silicon MEMS processing technologies. The sensor consists of a ring shaped movable electrode, an extremely thin (15 μm) spiral spring connected with the movable electrode and eight surrounding lower electrodes. When a gravitational acceleration 1 G (9.80 m/s2) is applied to the movable electrode, it moves and makes a short circuit between itself and a pair of the lower electrodes. The movable electrode comes in contact with different surrounding electrodes depending on the tilt angle of the chip. Therefore, it is possible to detect the tilt. The tilt sensor was fabricated utilizing the following MEMS processes including anodic bonding of an extremely thin 60 μm-thick silicon wafer on a glass substrate, photolithography on the silicon film and dry etching the silicon film using an inductively coupled plasma (ICP) dry etcher. Then, the underneath glass was selectively etched off using a hydrofluoric (HF) solution to release the movable parts. Since the device layers were fabricated on a single-crystal silicon, it enables to fabricate stress free silicon spring. The sensor successfully detected the tilt of the chip.

Wet Etched High Aspect Ratio Microstructures on Quartz for MEMS Applications

Z cut α-quartz wafers were etched in saturated ammonium bifluoride solution at 87 degrees C. The side wall profiles were observed using the scanning electron microscopy (SEM) and plotted dependent on the polar direction. This research focused on investigating high aspect ratio trench and through-hole, which were dependent on the polar direction to the crystal axis. Aspect ratio in dependence on polar direction was also plotted and microchannels with aspect ratio > 3 could be achieved at the polar angle between 30° to 60°. The possibility of application for microcapillary was discussed, and the trench at 45° was considered best. Double-sided etching technique was used for manufacturing through-hole structures. Through-hole at 0° was demonstrated effective for fabrication of capacitive MEMS tilt sensor. Through-holes at 15° and 105° were proposed for fabrication of 90°-arranged two axis capactive tilt sensor, taking advantage of the twofold symmetry property around X axis and threefold symmetry property around Z axis.