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Null values at constant intervals #5
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@fu-hsi yes I have the same issue. I am also getting NULL in passive mode. I will try increasing the timeout as you suggest and let you know. |
As noted by adafruit (https://cdn-learn.adafruit.com/downloads/pdf/pm25-air-quality-sensor.pdf , pg.13) there is a delay in the refresh rate abound 2.3 seconds max when there is no change in the particle counting, but it can speed up to 200-800ms refresh rate. |
It's referred to the Active mode (default). From official documentation:
But in our example (Passive mode) response time is less than 1s, but I recommend setting to 2s. |
Looks familiar?
In passive mode I receive NULL values from PMS 7003 sensor with constant intervals.
I have not received any complaints from others, these are my observations only.
Simple solution without modify library:
Increase default timeout value for readUntil().
E.g.
In next release I will use flush() after all commands to the sensor to be sure that the whole message has arrived.
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