I recently purchased the breakout board featuring the SGX-4NO-250 electrochemical NO gas sensor. I have several questions about its usage and calibration:
Is the sensor module (SGX-4NO-250) factory calibrated, and does it come with a sensitivity coefficient or calibration certificate?
What is the expected output format from the breakout board (e.g., raw ADC counts, voltage, or pre-calculated ppm)?
Is there any documentation available regarding how to convert the digital output to actual NO gas concentration in ppm?
I’m planning to use this board for experimental NO detection in human breath and skin emissions, and having accurate calibration data would be critical for my measurements.
Originally submitted via email support on 9 April 2025. Migrated to the forum for community visibility.
Calibration certificates may be available on the SGX Sensortech website.
The expected output differs for each sensor. You can use the Arduino library to see how PPM values are calculated:
Useful examples are available at:
You will need to create the sensorType struct for the SGX-4NO sensor in-code, as the library currently has configurations for SGX-4NO2, SGX-4CO, and SGX-4SO2. The SGX-4NO configuration is being prepared and will be added to the library. Once the configuration data is correct, the measurements will be accurate in PPM. Since we don’t have a chamber and test gases to verify exact calibration by ppm, this is the closest we can get.
I’ve reviewed the datasheet and examples provided, and I understand that the SGX-4NO-250 sensor currently doesn’t have a predefined configuration in the Arduino library. I’ll wait for the configuration update.
In the meantime, I’m using the sensor in a research setup for relative NO measurements, and the current workflow is working well. Once the configuration is ready, I’d like to test the ppm-calibrated output as well.
The configuration for the nitric oxide sensor has been completed and is now available at:
You can update just this file and use it in the example. When testing in a controlled environment, you may need to adjust the ‘internal zero calibration’ setting so that it reads 0 when there is no concentration of the gas present. This is the only value that may require adjustment. Please test it and provide any feedback.