User Manual

75
Lesson 30 MQ-2 Gas Sensor
Introduction
Gas Sensor MQ-2 is for flammable gas and smoke detection by measuring concentrations of
combustible gases in the air. They are often used for detecting smoke and flammable gasses
in households, industry or automobiles.
Components
- 1 * SunFounder Uno board
- 1 * USB data cable
- 1 * MQ-2 Gas sensor module
- Several jumper wires
Experimental Principle
MQ-2 gas sensor applies SnO2 (an oxygen-deficient n-type semiconductor) which has a
lower conductivity in the clear air as a gas-sensing material. In an atmosphere where there
may be inflammable gases, the conductivity of the gas sensor raises along with the
inflammable gas concentration increases. MQ-2 performs a good detection to different
inflammable gases such as natural gas, especially sensitive to liquefied gas, propane and
hydrogen. The higher the concentration is, the greater the conductivity will be, thus
changing the output signal.
In this experiment, release a small amount of smoke or flammable gas around the sensor and
watch the value at A0 increase. Once the concentration of the gas exceeds a limit, the LED
attached to pin 13 of Uno will light up.
Experimental Procedures
Step 1: Build the circuit
MQ-2 Gas Sensor Module SunFounder Uno
OUT ----------------------------------------- A0
VCC ----------------------------------------- 5V
GND --------------------------------------- GND
SunFounder