Commonly used domestic methane sensor and its advantages and disadvantages it is introduced. On this basis

design a methane sensor based on principle of non-dispersive infrared（ NDIR）. The sensor designs weak signal amplification circuit aiming at characteristics of infrared detector output. The output signal of infrared detector is amplified by AD8552; the signal of filtered and amplified is sampled conversion by AD7190

in order to reduce the influence of noise

a combination of hardware and software is used

in addition

through experimental measurements of standard methane gas at range of different concentration

fit and obtain relationship between gas concentration and ratio of voltage difference of detector output

according to the obtained curve and data analysis

se

lects concentration calculation method of piecewise interpolation. and then realize the methane real-time measurement. Finally

measurement results of methane at 0 %

5. 05 % are given.