mq7 and mq2 gas sensor help

Other Hardware Sensors
1

can anyone help me on how to code this 2 sensors i already read some of post but i cant understand where this 2 came from
37143 x-3.178 on sir thermike code How can I convert AnalogRead to something useful? - Programming Questions - Arduino Forum .. can someone help me plss .. thank you.

this code...

/ get CO ppm
float get_CO (float ratio){
float ppm = 0.0;
ppm = 37143 * pow (ratio, -3.178);
return ppm;

2

plsss help me.. i cant understand how the correlation works in mq2 and mq7 sensor works.. plsss help http://www.parallax.com/Portals/0/Downloads/docs/prod/sens/MQ-7.pdf

3

check my post - http://forum.arduino.cc/index.php/topic,55780.0.html -

4

these numbers come typically from the datasheet from the sensor, optionally adjusted to operational voltages or so.

It is explained - How can I convert AnalogRead to something useful? - Programming Questions - Arduino Forum -

just as I said in your other thread.

5

@tungaw14, stop cross-posting.