Design and fabrication of mirco-pendulum accelerometer

Abstract

In this project, a prototype of a micro-pendulum accelerometer was designed and fabricated. The prototype purpose is to simulate a micro-pendulum accelerometer to be fixed in a smart pen. The prototype, consisting of a pendulum structure, a hanging proof-mass and a capacitive plate, was design to be as similar as possible to the real accelerometer for a smart pen. By using photolithography techniques, the gold coated proof-mass and capacitive plates were fabricated from a silicon wafer, using transparency mask, designed using L-Edit.

As the performance of an accelerometer depends largely on its natural frequency, analysis on the natural frequency was done on the accelerometer. With the help of various tools and software, the natural frequency and behaviour of the accelerometer was observed. Although the result might not be accurate for a real smart pen accelerometer, the prototype provides a rough idea of what one can expect for an actual smart pen micro-pendulum accelerometer.

Optimizations of the micro-pendulum accelerometer were also carried out using the ANSYS software. By change the parameter in ANSYS, observations were obtained and analysis, without the trouble on fabrication another prototype. These save time and money in the production of a micro-pendulum accelerometer. After all the analyses, it was found out that the best micro-pendulum accelerometer should be one with a good stable pendulum structure, a larger surface area proof-mass, hanging from short thick wires of high stiffness material.