Also is this device going to be safety critical?

If so be very careful, if you kill or injure yourself then fair enough but if someone else is relying on it then you might be sued (at the very least).

Either way, playing with poison gas without a gas mask is like playing with magnetrons and microwave transofmers - stupid.

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If you want to collect more data, email the manufacturer. . . In the mean time we are only guessing. We have no way of comparing the results to the concentration of CO in the air. Like I said before, much of this is guess work. The test results you got before would tend to indicate that the sensor is working, but you have no way of reliably calibrating it.

I would suggest that any further tesing is done at a distance (by using wires to extend the sensor?) and as I said twice before IN A WELL VENTILATED AREA!

I did not realise that the testing procedure had caused you such problems! That's my fault for not reading your thread fully.

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I soldered the sensor with a 2 m cable but did not put a mask....I was concentrating on the experiment and didnt take much precautions ...
Anyway I hope that it does not have a bad effect on my brain later on

TO Summarize what I m up to :

- sensor works fine in air ( comapring it to the datasheet's graph)
-when explosed to the CO it varies but yet we can't tell anything about the values because it needs to be calibrated and we don't know how
- we can't tell what must be the low heater voltage unless the company answers me (and it is not answering i need someone who is living in China to make them a call)

- Still confused if i must turn the heater ON or there is NO need

Am I right ???

 

Wikipedia says "A concentration of as little as 0.04% (400 parts per million) carbon monoxide in the air can be fatal." which isn't much so testing in a well ventilated area won't give adequate protection against poisoning.

You should wear a mask connected to a supply of fresh air, perhapps wearing a nose clip and breathing through a piece of tube with the other end in fresh air might do the job.

Edit:
Testing from a safe distance would be just as safe and more convenient to.

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I will do all of that in my second testings
But i need your opinion and to collect as much information as i can so i won't need a third test....

 

There's no way of calibrating it without a sample of carbon monoxide of a known concentration or a another calibrated instrument to compare it with.

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You are 100/100 right Hero
But pls can u tell me if what i understood is correct ? concerning the heater voltage ....Am i obliged to supplu the low then the high voltage even if i m not interested in measuring the methane???

 

the RL value is important too, you said you took it to be 13 K . I think it will be better to make it smaller

 

God Be With You in your second Testing ..........

 

I 'assumed' that testing in a well ventilated area (eg OUTSIDE) would be just like standing next to a car while its engine is running (since he is using an engine exhaust to provide the CO)

But I think we all agree that the best, and safest option is to keep as much distance as possible between the 'experimenter' and the source of the gas.

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After reading the datasheet, Do you think that if i need to measure the CO and not the methane, I just need to apply the low heater voltage and not both of them ????

Please i need your suggestions ...

 

The datasheet is for a different sensor than the one you have. So everyone is only guessing about yours.

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Uncle $crooge

 

I found ont MQ307A

Do you think that if i need to measure the CO and not the methane, I just need to apply the low heater voltage and not both of them ????

Please i need your suggestions ...

 

The datasheet for the newer MQ307A shows how to set its heater to measure CO and methane, but it doesn't say anything about your older sensor.

You should be using a modern sensor and have a datasheet and application notes for it. It would explain if you need to swich the heater voltage high and low and explain why. It would have cautions about exposure to the deadly gas. It would explain if its accuracy is affected by some of the many other elements in an engine's exhaust including its temperature. It would show how to calibrate it.

You are working in the Dark Ages.

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Uncle $crooge

 

I am working now on the MQ307A
Is it necessarily to apply high (30sec) and heater 120sec??? even if i m interested just in the CO testings ?