Bernhard Boser (Advisor)

Resonant MEMS sensors are commonly used for sensing pressure, mass, force, strain, and acceleration. Resonant readout is particularly attractive for piezoelectric sensors, since it is the only method that allows measurement of static or slowly-varying quantities. Fundamentally, resonant readout relies on a fixed dependence between the quantity to be measured and the resonant frequency of a mechanical structure. However, the resonant frequency is generally also a strong function of several unwanted variables, including temperature, fabrication variability, and packaging stress. One...

The simplicity and low cost of capacitive interfaces makes them very attractive for wireless charging stations. Major benefits include low electromagnetic radiation and the amenability of combined power and data transfer over the same interface. We present a capacitive power transfer circuit using series resonance that enables efficient high frequency, moderate voltage operation through soft-switching. An included analysis predicts fundamental limitations on the maximum achievable efficiency for a given amount of coupling capacitance and is used to find the optimum circuit component...

Optical 3D imagers for gesture recognition, such as Microsoft Kinect, suffer from large size and high power consumption. Their performance depends on ambient illumination and they generally cannot operate in sunlight. These factors have prevented widespread adoption of gesture interfaces in energy- and volume-limited environments such as tablets and smartphones. Gesture recognition using sound is an attractive candidate to overcome these difficulties because of the potential for chip-scale solution size, low power consumption, and ambient light insensitivity. Our research focuses on...

This project aims to develop a compact and self-contained universal test platform for DSP-based control of MEMS gyroscopes and resonant sensors. Many operating modes require features not available in off-the-shelf laboratory instruments, and it is difficult to perform sensor testing and validation with laboratory test equipment due to size and power constraints. We have implemented a multi- channel digital lock-in amplifier in FPGA hardware, providing PLLs, modulators, demodulators, filters, and the capability to add custom functionality. Software-based baseband DSP allows...