Dear Sir,
Are there any sensor modules called "precalibrated sensors" for CO,CO2 at market ?
As I heard those sensors don't want to calibrate in known concentration of the gas we want to measure. It is difficult to create known concentration of gases at home.
So any method to get gas level in ppm range for following sensor? This sensor data sheet asked the resistance for known concentration of required gas to measure the gas in ppm level.
Please help me to my school project.
Thanks.
This is a sensor that is calibrated.
It costs 249 dollars.
This one costs more than 400 euros, http://www.theben.de/de/Produkte/KLIMA/Sensorik/CO2-sensoren/AMUN-716-R
The more professional or industrial quality you want, the more you have to pay.
For home use, I think devices that measure carbon dioxide are between 100 and 200 euros.
But they also measure other gasses, so you don't know for sure if it is measuring only the carbon dioxide.
You could 'calibrate' a sensor by yourselve. Just put it in a jar and fill that with 100% NOx, that's your zero-point. Then fill it with a known mix of your desired gas, and thats your upper value.
A known mix could be: fresh air or your own breath. Both should contain a certain percentage of CO2
Assume it's linear between those two points and you're done.
o_lampe:
You could 'calibrate' a sensor by yourselve. Just put it in a jar and fill that with 100% NOx, that's your zero-point. Then fill it with a known mix of your desired gas, and thats your upper value.
A known mix could be: fresh air or your own breath. Both should contain a certain percentage of CO2Assume it's linear between those two points and you're done.
Dear o_lampe,
Many thanks for your reply.
Can't I use following 2 methods?
When the sensor in clean air take the sensor value as zero point (reference point) and next put the sensor in known CO percent and take the value as upper value. Take it as liner in those two values.
The sensor data sheet(MQ7) says
Detecting range:20ppm-2000ppm carbon monoxide
I can get sensor out put voltage 0V to 5V in serial monitor of arduino. Then taking 0V as 20ppm and 5V as 2000ppm can I get the values consider it as liner.
(MQ7 CO sensor data sheet >> http://www.elechouse.com/elechouse/images/product/MQ-x/MQ-7.pdf )
I must be thankful to you if you will kindly reply soon.
Thanks
I dont know, how much CO is in fresh air.
Also CO is toxic ( other that CO2 ). Your breath shouldn't contain CO.
2000ppm is the same as 2%.
You would need a sample of gas, that contains 2% CO to set the 100% value. But over time the CO would be 'consumed' by the sensor, so you would actually need a constant flow of gas to let the sensor-output settle down to a steady value. ( Can take a few minutes )
Another Option is to use an already working CO-meter and put both in the same Environment to compare their values.
o_lampe:
2000ppm is the same as 2%.
Hello o_lampe,
Is this correct ? 2000ppm = 2% Or
2000ppm=0.2%...?
It means 10000ppm=1% is this correct or your one is correct ?
Waiting for your reply.
Thanks
Abkad:
o_lampe:
2000ppm is the same as 2%.Hello o_lampe,
Is this correct ? 2000ppm = 2% Or
2000ppm=0.2%...?
It means 10000ppm=1% is this correct or your one is correct ?
Waiting for your reply.
Thanks
You could be right, but what use would a sensor have with a max range of 0.2% ?
That was my thought, when I wrote it and decided, I must have made a miscalculation.