MQ-5 Gas Sensor Module

The MQ series of gas sensors use a small heater inside with an electro-chemical sensor. They are sensitive for a range of gasses and are used indoors at room temperature.

They can be calibrated more or less but a know concentration of the measured gas or gasses is needed for that.

Chip: LM393, ZYMQ-2 gas sensors
   with a signal output instruction.
   dual signal output (analog output, and TTL level output)
   TTL output
   0~5V analog output voltage, the higher the concentration the higher the voltage.
   the gas, natural gas, city gas, smoke better sensitivity.
   with a long service life and reliable stability
   rapid response and recovery characteristics

MQ-2

Sensitive for Methane, Butane, LPG, smoke.
This sensor is sensitive for flamable and combustible gasses.
The MQ-2 at seeed: http://www.seeedstudio.com/wiki/Grove_-_Gas_Sensor%28MQ2%29

MQ-3

Sensitive for Alcohol, Ethanol, smoke
The heater uses 5V
The Arduino blog about the "breathalyzer" using a MQ-3 :http://arduino.cc/blog/2010/09/23/arduino-breathalyzer-calibrating-the-mq-3-alcohol-sensor/

MQ-4

Sensitive for Methane, CNG Gas

MQ-5

Sensitive for Natural gas, LPG
The MQ-5 at seeed: http://www.seeedstudio.com/wiki/Electronic_brick_-_Gas_sensor%28MQ5%29 and http://www.seeedstudio.com/wiki/Gas_Sensor_-_MQ5

MQ-6

Sensitive for LPG, butane gas
The MQ-6 at seeed: http://www.seeedstudio.com/wiki/Electronic_brick_-_Gas_sensor%28MQ6%29

MQ-7

Sensitive for Carbon Monoxide
A library for the MQ-7 : http://thesis.jmsaavedra.com/prototypes/software/mq-7-breakout-arduino-library/

MQ-8

Sensitive for Hydrogen Gas

MQ-9

Sensitive for Carbon Monoxide, flammable gasses.

MQ135

For Air Quality
Sensitive for Benzene, Alcohol, smoke.
An example how to use it: http://wiring.org.co/learning/basics/airqualitymq135.html