Energy-Aware Gas Sensing Using Wireless Sensor Networks

Wireless Sensor Networks (WSN) have recently been applied in various monitoring applications including hazardous gases detection. However, being a major power consumer of a sensor node, off-the-shelf gas sensors significantly constrain its lifetime. In this paper we present a WSN for hazardous gases detection with a special focus on the power consumption of the sensor node. The sensor node is designed on the basis of a planar catalytic sensor with improved power consumption characteristics. The power supply of the node is divided into digital and analogue parts. This is done to guarantee digital remote control of the device even when the analogue power source has already been depleted by the sensing circuit. In addition, we propose a differential gas measurement approach along with specific heating pulses for the sensor to secure substantial energy saving. The resulting average power consumption is 1.45 and 2.64 mW for the gas sensor and the sensor node respectively. With our techniques, the sensor node lifetime improves from 187 days up to 641 days.