SEN55 always the same value from PMx

Sensors Environmental
1

Hello,

I am currently working with the SEN55 sensor and am experiencing an issue where the PM1, PM2.5, PM4, and PM10 values are always returning the same readings, which seems incorrect. These values are supposed to vary based on the air quality, and it is unusual that they remain static, especially considering they have different scales.

For example, today’s expected values should be:

  • PM2.5: 95
  • PM10: 47

However, the readings I am receiving are always like:

... 'pm10p0': 13.9, 'pm4p0': 13.9, 'pm1p0': 13.2, 'pm2p5': 13.9, ...

Could you please assist me in understanding why this is happening and if there is a solution to resolve it? Any guidance would be greatly appreciated.

Thank you for your support.

Best regards,
Daniele

2

I have worked on the SPS30, later the SEN55 and now working on the new SEN66. The output numbers can be very close after a longer time running. In my observations for the SEN55 the PM2.5, PM4,0 and PM10 numbers would often be the same. If you breath into the device, you should see a change.

I am not using the Sensirion library, but created my own starting with the SPS30. If you want to check the SEN55 library / results that I got see GitHub - paulvha/sen55: Arduino library Sen55 and/or want to see the SEN66 GitHub - paulvha/SEN6X: Sensirion SEN6x library for Arduino. The later is work-on-progress, but does contain compares against SPS30 and SEN55.

It seemed also that not all the PM numbers are really measured, but estimated based on other readings. See the SEN55.odt in the mentioned library.

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