Fabrication and design of an auto ventilation controller using micro gas sensor for the clean room/building environment

With the growing attention to environmental problems and the increase of standard of living, there are imperative needs for gas sensors with high sensitivity and excellent selectivity in air quality monitoring. Domestic environmental monitoring is an important aspect nowadays. We have tried to develop a sensor that can help to monitor the presence of harmful gases. An auto ventilation controller has been developed to expel out the toxic gases (CO, NO/sub 2/, CH/sub 4/, HCHO, C/sub 3/H/sub 8/, CO/sub 2/) from the residential rooms/buildings. It is developed to save energy and to clean the environment. For this, microelectronic semiconductor type gas sensor was made by MEMS (microelectromechanical system) technology and a control electronic circuit was designed. The potential of the controller was further systematically studied for its sensing characteristics against various toxic gases. It has been observed that sensor is effective in detecting few gases even up to very small concentration levels. The developed sensor is inexpensive, has small size, sufficient sensitivity and immunity to environmental conditions for applications. The functioning and use of the sensor is very simple and reliable.