Interfacing CO2 gas sensor with AVR Microcontroller

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I just bought CO2 gas sensor with 4 pin (VCC,GND,Digitial Output,Analog Output). But I don't know exactly how to interface it with AVR microcontroller ?
Do i need to connect it to ADC ? or it come with ADC module ? I have attach the picture too.
Thanks for help

 

First amplify 30-50mV to 0-5V then ADC.

I'm not sure for TTL data.

Post datasheet or some better informations about this sensor module.


Best regards,
Peter
 

Thanks for respond,
I recently contact the seller for datasheet detail, and he gave me an ADC0809 datasheet from National Semiconductor. i thought it has an internal ADC. So how to use the TTL data?
 

They give you ADC IC 8-bit. This IC have poor resolution of 256 ADC steps. You need datasheet for this module, if there is no such data than you need to test this.

Try with CO2 for welding. You can find this on any corner, just search MAG tech or welding device with CO2 gas.



Best regards,
Peter
 

I have used that sensor module. It is very easy to use. It has 4 pins. Vcc (should be connected to +5V), GND (should be connected to ground), Dout (TTL out, can be interfaced to digital input pin of uC), Aout (can be interfaced to uC ADC pin). If there is a gas leak the Dout pin goes high. Aout pin o/p voltage can be set using the preset. The preset actually sets the threshold of sensing. If you need more details then mention the link from where you purchased the sensor module. It has nothing to do with ADC0804/8/9. If you use 8051 uC then you may need to use an external ADC but ADC0804/8/9 doesn't give good resoulution. Use any LTC 10 bit I2C or SPI ADC.

https://probots.co.in/index.php?main_page=index&cPath=9&zenid=d06d341df22047d874554fa6ef9bc0e3
 
Last edited:

So, i can directly use TTL ? so, where should i connect the TTL pin to the microcontroller ?
or where can I find the tutorial regarding interfacing TTL with microcontroller?

Did you mean test for calibration?

Thanks,

- - - Updated - - -

@jayanth.devarayanadurga
TTL just give us information high and low?
so you have this datasheet module ?
i bought it from ebay -> http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=110888030682&ssPageName=ADME:X:RTQ:US:1123
So if I want to know about gas concentration, I have to use the Analog output and amplify that?

Thanks,
 

Best place for searching information and datasheet is manufacturer.

Test for everything, first to see does this works at all, than calibration. I want to say you cant trust manufacturer which dont supply documentation for their product.

Try to find curve with data about concentrarion related to output analog voltage and try to find min and max values of CO2 measurement.

These modules should be always tested, specially if they are used for safety.


Best regards,
Peter
 

Yes. Aout gives voltage proportional to the concentration of gas. Dout can be interfaced to any digital input pin of uC. When there is gas detect the Dout pin and hence uC input pin interfaced with Dout goes high. You have to write code which tests if this pin is high or low. If high then do what you want when there is a gas detect and when low you can execute any other piece of code.

**broken link removed**



 

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hello
i bought 2 sensor model :mh3-h2s 3 pin and md 440d 5 pin from winsensor comapny .please introduce circuit for connect with micro .Either directly or indirectly
 

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