There are numerous areas where air quality or gas composition can enhance the quality of life and safety. These areas include health and safety (such as detection of methane during mining), medical (breath diagnosis), law enforcement (such as detection of illicit drugs), and vehicle safety (such as checking for alcohol and drugs for safe driving). Current technology meets some of the needs but is expensive, bulky and power hungry. This project proposes a miniature, ultra-low power, sensitive, microbridge thermal conductivity based gas sensor that uses less than 50 microwatts of power. In addition, the reproducibility and stability of the sensor are excellent achieving over 30 billion measurements before failure.
The key advantages of the proposed sensors are their ultra-low power consumption and the lack of need for recalibration in the field. This results in substantial cost savings since most chemical sensors require calibrations at given time intervals as well as frequent changes in the battery power. As the sensor is conductimetric, the instrumentation for measurement is very straight forward. The team has investigated methods for minimizing noise and improving stability of the data with pulsed operation. The team has also investigated transient measurements for which the response time is recorded as a function of the gas composition.
