ACCELEROMETER SYSTEM FOR TREMOR ANALYSIS

Abstract

Micro fabricated accelerometer sensors have been developed to measure acceleration in a variety ofapplications, including automobile airbag crash sensors and seismic activity monitors. In this paper a threedimensional accelerometer sensor is used for measuring involuntary human hand motion (tremor). This human hand motion sensor uses three single-axis accelerometers fabricated with a free scale semiconductor. The size and mass of the sensor are limited to avoid altering hand motion being measured. Acceleration of the sensor forces displacement of the proof mass, and the displacement is sensed using differential capacitors.
The accelerometer dies are packaged in leadless chip carriers (LCCs), and the LCCs are arranged in a threeaxis configuration. A microcontroller circuit is constructed to convert the differential capacitance signal intoan analog signal and then into a digital signal before being read into a CRO or a computer. The data acquisition program allows real-time analysis of the acceleration data, as well as storage of the data for more sophisticated subsequent analysis. Generally EMGs (Electro Myogram) can be used for the analysis of tremors and due to their high cost they can be replaced by storage oscilloscopes for research & monitoring purposes. This process can be further enhanced by interfacing the microcontroller to a computer with the help of the i2c bus interface and the waveforms can be easily stored and analyzed. The three dimensional accelerometer sensor has been demonstrated in the intended application of measuring involuntary human hand motions.