PID Gas sensor interfacing with ADC
I am interfacing this gas sensor to the ADC of TI CC1352P. May I know can I directly connect the output of this gas sensor to ADC (I mean after the gas sensor output I will keep an RC circuit with some cut off frequency less than 100Hz) or do I need to place a unity gain buffer before the ADC.
My calculations about the gas sensor is given below.
I found some circuits in this application note from Alphasense.
The below imabe from the application note.This image is not clear to me.May I know the portion shown in the red box represents the gas sensor.
I beleve I can use the image shown below in the Yellow box.Kindly share your thoughts.
1 answer
The following users marked this post as Works for me:
| User | Comment | Date |
|---|---|---|
| newbie | (no comment) | Aug 18, 2025 at 07:48 |
Would the section shown in the red box represent the gas sensor?
No, all of that circuit represents the whole device and its internal working. What's in red is only a part of the internal circuits.
I believe I can use the image shown below in the Yellow box. Kindly share your thoughts.
That is the whole device as a black box equivalent.
The offset of the sensor varies from 40 mV to 100 mV. In this case, how do I set the threshold? The system should trigger if 20 ppm or more is detected.
You have to adjust it with a calibrated gas sample. This is how it's normally done. It can be quite complicated because you need to use a gas sample with the right dilution and, you need to flush that sample out to atmosphere to double check it returns to the original offset. It's basically for a professional if you want to sell or use an accurate unit. I don't know what facilities you have.
Answer above copied from my SE answer here.
May I know can I directly connect the output of this gas sensor to ADC (I mean after the gas sensor output I will keep an RC circuit with some cut off frequency less than 100Hz) or do I need to place a unity gain buffer before the ADC.
Yes, that should be no problem but, you can also use an op-amp as a buffer should the ADC require a lower signal source output impedance.
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