The hazardous gas concentration can be measured using optical, catalytic and semiconducting gas sensors [16]. The major problem associated with the measurement of combustible gas concentration in autonomous devices is the high power consumption associated with the sensors. In this work, we have used a 2D semiconductor gas sensor produced on an aluminum membrane [13]. This type of sensor is characterized by high sensitivity, long lifetime and relatively
low energy consumption (see Table 1 ‘2D semiconductor sensor’).Besides, the sensor has an ExsIU/ExdIIB+H2U degree of implosion protection (see the protection requirements in [17]), which makes it safe to use in a hazardous environment. The system works by heating the sensitive layer of the sensor to a temperature of around 500 ◦C, and then measuring the conductivity of the semiconductor, which is affected by the gas concentration. Typical applications [11] use a continuous measurement mode in which the semiconductor is kept at a constant temperature. In our system, instead, to further decrease the energy consumption [18], the sensitive layer is only heated when measurements are required, which occurs at regular intervals, i.e., we replaced the continuous measurement mode with the pulse of a PWM signal implementing a duty-cycle mode [19].