Irregular measurements SDS011

Hi All,

I am new to this forum and new to the measurement cummunity.

I bought a Ai-Thinker ESP8266 NodeMCU V2 and Nova SDS011 to measure the PM concentration in my neighborhood. I managed to get everything connected and installed, but when i look at the device statistics, I notice that almost 1 in 4 measurements leads to an error. The temperature and humidity measurements go well, but the measurements of PM2,5 en PM10 go wrong for approximately 25% of the cases. In that case, there is no measurement ( ‘-’ as value for the measurement) and also my sensor does not appear on anymore. The measurements take place every 300 seconds and there is always a good wifi-connection with the device (i can always access it, even when the measurements go wrong).

Unfortunately, I have no rights yet to post images in the forum to clarify the problem.

Any idea what can cause the problem?



Hello and welcome!

About the failures, the first thing to consider is the power supply.

About the dissapearance from the sensor map, this happens (correct me if my wrong) because the update interval surpasses the 5 minute mark. Btw, the default interval is half less than your current.

Welcome Edwin!
Could you send me the IDs of the sensor: API ID (the one from the map) and board ID.
As @air-ais told, it is probably a power supply issue: use a USB charger with more than 1500 mA. The specs should be written on it.

Have you changed something in the firmware ? It should be 145 s.

Actually I don’t really understand where you see this:

In the web interface ? In

If the sending frequency is changed to 300 s. it is normal that the sensor regularly disappears from the map. The map is optimized for the 145 s. rhythm.

Another possibility would be bad cable connections. Sometimes the Dupont cables are not tight enough.Try to make them tighter or find some KONTAKT 60 fluid.

Thanks a lot for your responses. My excuses if my questions weren’t clear enough.

  1. My power supply is 1 A. It was provided by the webshop where I bought the set.

  2. The sensor-id is #82691

  3. My question about failing PM measurements (but good measurements from the temp/humidity sensor) is shown on this image :

  4. The number of errors is shown here (25 of the 96 measurements went wrong):

  5. However, we are now a full day later, and the number of errors has dropped significantely. It is now less than 10%. It looks likes the sensor needed some time 'to run properly???

  6. I changed the sending frequency to 300 seconds, because I read on a forum, that it increases the lifespan of the sensor. I changed it in the configuration part of the web interface under more settings (“Measuring interval (sec)”).

Kind regards,

Looks good:

1A is not enough. Tinytronics should have contacted us… It can basically be the reason.

As you wish… It does not really matter.

The hole in the curve will appear on the other graphics (with the board ID), no problem.

Thanks! I changed the power supply to 5V / 2.1A. The number of errors dropped significantly. The first 52 measurements led to 1 error. Problem solved I hope.

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I have told it… It is always the PSU.