get right rpm in mq sensor please help

Projects Programming
1

hi i am yogi, i am a beginner now i working on my project with some mq sesors like mq 135, mq 7 and mq 136, but in any reference that i see i couldn't find any programing that will make the data in right rpm, i try to read how to calibrate it but i still not understand, is there someone know the program for this or have an experience i this? please help me.

2

Please post a link to the datasheets for the sensors you are using.

Also post the program you have tried and tell us what it actually does and what you want it to do that is different.

...R

3

i haven't make the program yet, most of the web that i find they just using analogRead that put ppm in the end, that seems weird for me because some web they said that we need to calibrate than i don't know how to calibrate. this is some of the datasheet

MQ-7.pdf (52.2 KB)

MQ136.pdf (158 KB)

4

Those links are to sensors for carbon monoxide and sulphur dioxide.

How do you expect to detect RPM with them?

And in case of doubt RPM usually means "revolutions per minute"

...R

5

sorry, i mean that ppm, i have read some website how to calibrate it. finally i undesrstand but it need a real measurement like what the sensor read in the known ppm

6

Its not that hard ive done it in one of my projects. If you want ppm of co2 for example then from last statistics published week ago it was ~402ppm.

So if you will take your sensor which measures co2 whatever reading you will get (assuming 48hr non stop warmup period) will be your calibration value for co2.

7

yogiwindu22:
sorry, i mean that ppm,

If you edit your Original Post you can correct the title

...R

8

Robin2:
If you edit your Original Post you can correct the title

...R

thank you

9

Unfortunately those sensors detect several gases, not just the one of interest.

You can calibrate them by using known mixtures of gases, but the response will drift over time regardless. Be sure to "burn them in" for 48 or more hours before attempting any calibration.

This amazing blog article tells you more about the sensors, and explains how to make an "electronic nose" with several different MQ sensors.