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Interfacing Gas sensor with 3.3V ucontrollers

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shubh1994

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I am trying to interface MQ7 (CO) with TI Stellaris launchpad (operating voltage is 3.3V) but according to datasheet MQ7 requires Vh= 5v
and Vl=1.4v.
So, how to interface MQ gas sensors with 3.3v microcontroller????
 

Is it not possible to use this MQ7 (gas sensor) with 3.3ucontroller directly without using level shifter??
Can't we heat the heating element will 3.3V??
 

It might work. See this circuit. **broken link removed**

It is for 5V. Just change the resistors connected to LEDs to 180E if you use 3.3V. Op Amp is used as a Comparator. Use Op Amp like OPA350 or any other op amp which works from 2.5V to 5V.


Here is a level sensor circuit but level sensor is of no use for your purpose.

https://www.incrediblediy.com/2013/02/simple-33v5v-level-shifter.html
 
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