In order to resolve the issues related to wired systems, the
paradigm of WSN has been recently adopted. Hazardous gases may
be detected with small, inexpensive wireless sensor devices which
are located throughout the territory and operate autonomously on
a co-operative basis [3]. There are two main strategies for detecting
target gases by a sensor node. The first strategy is ‘power efficient’
and uses a light sensor in conjunction with a colorimetric chemical
sensing film [7] or a silicon bridgetype micro-gas sensing film [8].
These kinds of sensors, however, do not have sufficient sensitivity
and accuracy, resulting in long response times in the order of
300 s [7] which fail to meet the requirements of safety standards
[9]. The second ‘power hungry’ strategy is based mainly on a laser
spectroscopic sensor [10] or catalytic and semiconductor sensors
[11–13]. The laser spectroscopic sensor has high sensitivity but may
consume current up to 800 mA [10], which is a limiting factor for
deploying the nodes. Catalytic and semiconductor sensors exploit
chemical reactions on their surface to provide good sensitivity and
selectivity along with short response time. Besides, they have lower
power consumption (see Table 1) than the laser spectroscopic sensor.
Table 1 presents the power consumption of some off-the-shelf
sensors with typical functions applied in WSNs. In this work we use
the 2D semiconductor gas sensor [13] numbered 4th in Table 1, discussed
in more details in Section 3.1. This sensor ensures early gas leak detection, has low response time and supports a pulse heating
mode which results in even lower power consumption. So, our
second goal is to prolong the long-term operation of the wireless
nodes with the use of an on board semiconductor gas sensor.