Using semiconductor gas sensor MQ—2

design an instrument for flammable gas volume fraction detection and alarm

which is composed of combustible gas sensor

analog/digital conversion circuit

microcontroller

display circuit

acousto-optic alarm circuit.MQ—2 sensor converts gas volume fraction to voltage signal

transmit to A/D conversion circuit

signal after conversion is transmitted to STC89C52 MCU for processing

then gas volume fraction is displayed by control display unit

at the same time control and driving alarm circuit to achieve sound and light alarm.Experiments show that gas detection precision of the detection and alarm instrument on isobutane

methane

natural gas and other combustible gas reaches 0.01 %

it has characteristics of stable detection performance

good linearity

simple circuit

low cost

miniaturization

and convenient debugging.