MQ-8 gas sensor is suitable for sensing is Hydrogen Gas which with lower conductivity in clean air.
When hydrogen gas exists, the sensor’s conductivity gets higher along with the gas concentration rising.
MQ-8 gas sensor has high sensitivity to hydrogen gas, also has anti interference to other gases.
The sensor’s output is an analog resistance.
This sensor can detect hydrogen, especially city gas.
It is a kind of low-cost sensor for kinds of applications.
It has good sensitivity to hydrogen gas in wide range.
Long lifespan, low cost and simple drive circuit
Small sensitivity to alcohol, LPG,cooking fumes
Stable and long life
Selective digital/analog output using toggle switch
High sensitivity and response time
Gas Sensor Pinout
The MQ-xx have six pins, most of the Gas sensors in these series will have six pins.
The center two pins are called as H pins (Heater pins),
Remaining pins both up & down side called as A and B pins.
Both pins are connected with separate electro-chemical sensor.
We can use both pins to bring output, only thing is No H pins are connected with micro controller or Arduino, because it draws much current.
Gas Sensor Arduino Hookup
As per the wiring diagram, the MQ-XX series sensor can be connected with Arduino board.
The resistor (10K) connected with B pin to Gnd to maintain sensitivity level of Gas sensor at particular point, if you need variable sensitivity from your sensor you can use variable resistor instead for 10K.
A and H pins are connected together with +5V power source pin of Arduino board, and Separate H pin is connected with GND, Both B pins are connected together and linked to Arduino’s Analog pin A0.