Abstract
An array consisting of four commercial gas sensors with target
specifications for hydrocarbons, ammonia, alcohol, explosive gases has
been constructed and tested. The sensors in the array operate in the
dynamic mode upon the temperature modulation from 350°C to 500°C. Changes
in the sensor operating temperature lead to distinct resistance responses
affected by the gas type, its concentration and the humidity level. The
measurements are performed upon various hydrogen (17-3000 ppm), methane
(167-3000 ppm) and propane (167-3000 ppm) concentrations at relative
humidity levels of 0-75%RH. The measured dynamic response signals are
further processed with the Discrete Fourier Transform. Absolute values of
the dc component and the first five harmonics of each sensor are analysed
by a feed-forward back-propagation neural network. The ultimate aim of
this research is to achieve a reliable hydrogen detection despite an
interference of the humidity and residual gases.
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