SDS011 warm up time

As for now, we got 15 seconds of warm up time for SDS011.

According to Laser Dust Sensor Control Protocol V1.3 from NovaFitness, page 8:

Notes: The data is stable when the sensor works after 30 seconds;

So my question is: Why 15 seconds instead of manufacturer recommended 30?

I can’t remember how it really works but I think you can also add some other ms before it really starts to measure. Actually it should make a few measurements and calculate an average. Let’s analyse the firmware.

The 30 seconds are for the worst case scenario of a 1 meter pipe. But we normally use a pipe of 20 cm. So outside air will reach the sensor much faster.
We needed to minimize the runtime of the sensor to get a longer lifetime.

Do you have any information from NovaFitness to back up this statement? Or is it just your observation?

This is our observation. The first months our firmware couldn’t shut down the SDS011. So we had measurements to compare with.
The ‘communication’ with Nova Fitness isn’t really easy. We tried to get the protocol documentation for the sensor. After weeks and many emails we got this info …

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