about mq2 sensor

Other Hardware Sensors
1

hi
i am trying to detect different gases like Co2,Nh4,lpg,H2 and other using mq2. my doubt is in the datasheet given various curves for different gases, so
1)how can i differentiate gases as i can get same voltage for differnt gases.(in the graph if get Rs/Ro ==1, is that mean that i have 600ppm of lpg and propane;1000 ppm of h2;4000ppm of alcohol )
2)is the graph platted by taking one gas at a time or combining all gases?

thank u
Vitry.....

2

With that sensor, I don't believe you can distinguish between the different gases that it responds to. The graph will have been plotted taking one gas at a time.

3

It is like a variable resistor. If it detects "something" the resistance is lowered for a "certain" amount.
http://playground.arduino.cc/Main/MQGasSensors

4

thanks dc42

5

hi

i am doing a project with mq-2 to detect different gases but now it is not possible to do that. is there any way to detect different gases(my interest is co2,co,no2)without using dedicated sensors.any information will be grateful.

thanks
Vitry

6

No, sorry.

Some sensors are sensitive for CO or CO2, they can be used in a building because it assumed that there will be no other gasses.

The MQ2 is very sensitive for flamable gasses and it not ment to detect CO or CO2.