In this paper we present a wireless gas sensor network (WGSN)
for early gas leak detection and fast operator alarm. The network
consists of four units: a sensor node, a relay node, a network
coordinator, and a wireless actuator. The sensor node is equipped
with a microcontroller, a wireless modem, a battery power supply,
and a 2D semiconductor gas sensor. Since the sensor is the most
power ‘hungry’ component on board, we apply pulse width modulation
(PWM) for the heating of the sensor sensitive layer that
significantly reduces its energy consumption. In addition, to support
continuous monitoring of the environment, we have carefully
chosen low power consumption components and energy saving
modes during the sensor node development. The range of wireless
transmission is extended using the relay nodes, which support
communication between the sensor node and the network coordinator.
Whenever a hazardous gas is detected in the atmosphere, the
network coordinator alarms an operator by the GSM/GPRS or Ethernet
network and/or controls a gas emission source by the wireless
actuator.
The paper is organized as follows: Section 2 presents the system
overview, while Section 3 introduces the reader to the hardware
implementation of the system. Section 4 describes the algorithm of
network routine and emergency operation in an apartment house.
Experimental results are presented in Section 5. Finally, we conclude
in Section 6.