Thus, most of the efforts must be focused on finding the best
power-optimization strategy to permit the device to operate as
long as possible.
Many research groups are working on the development
of air monitoring systems based on WSNs; each solution
differs in the type of sensors used or in the achieved energyoptimization.
Wang et al. in [6] present a sensor network for
outdoor installations with a solar panel mounted on top of
the sensor node box to provide constant supply. In [7] the
authors have addressed the problem of energy by developing
a low-power SAW sensor and its frequency readout circuitry.
In [8] a miniaturized system has been realized in the form of a
bracelet to achieve a large scale monitoring network by letting
the people wear it. There are also some reports where the
efforts are focused on the reliability of the measuring system,
here, complex processing based on neural networks and fuzzy
algorithms are implemented in sensing nodes to reveal if a
dangerous situation occurs, hence the data are transmitted only
when it is necessary thus reducing the radio consumptions [9],
[10]. Other researchers focused their attention on the strategy
used to sense the environment. In [11]–[14] the solution
adopted to reduce the power consumption, relies on dutycycle
and results in extending the life of a node, still using
the sensor as indicated by the manufacturer. Other kind of
optimization were introduced in the hardware of nodes [11],
[15], achieving significant reduction of wasted power when
the device is in idle or sleeping state. Recently Somov et
al. [16] have presented a monitoring device that necessitates
very little energy, those have developed a new catalytic sensor
and the adequate sampling and processing algorithm. This
choice, although interesting, is not cost effective.
In this work we investigate new ways to reduce the energy
consumed by WGSN nodes, with respect to the current state of
the art, and considering commercially off-the-shelf available
sensors. We focus on the characterization of the sensors’ behavior
and firmware optimization. We have considered Carbon
Monoxide (CO), Volatile Organic Compounds (V OCs) and
Methane (CH4) as dangerous aerosol of indoor environments,
and we optimized the usage of these sensors using the same
environmental wireless network. An increasing interest is
growing towards the first two chemicals while natural gas
constitutes a serious hazard in indoor environment, thus it
is reasonable developing a distributed system which detect
multiple gases in the same ambient. The main contribution