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SCK 2.1 sensor board failures

Hi Lately I have discovered some sensor board failures on our #viadukaduk sensor group.

All 3 boards concerned, lost the VOC / CO2 sensors, one of them also the temp, humidity sensor, one has microphone issues - showing above 100dBA most of the time, but not all of the time - mostly int he night.

It seems the VOC, CO2 sensor is the most sensitive, vulnerable, at least in our area, climate and dust condition.

All of these sensors have been saved by reinstalling firmware from scratch and selectively enabling working sensors. However part of the functionality is gone.

Now already two with microphone issues. I was reading that water droplets could cause this. However the sensors setup didn’t change. So it’s not like there is a new saurce of water droplets around it or so. If it is about water then the sensor became considerably more sensitive after 1.5year of exposure.

I tried blowing them dry with compressed air - no success here.

Ok; here is some advice from experience dealing with water ingress.
The success or otherwise of this technique depends on how much water was involved; and how long was it immersed with power applied.

Firstly remove power from the kit including battery.

Secondly disconnect the dust sensor and remove the urban board from the data board.

Then you can use ethanol (70% pure) to remove water. This would be “hand sanitizer” grade of ethanol with only water used to dilute it. (No methanol or glycerine etc).
Dip the board briefly into the ethanol then blow it dry with your tin of canned air.
When the ethanol dries; it also dries out water.

It is likely to leave a white residue, which can be removed using a board cleaning solution.

Allow the board to dry completely before reconnecting every thing. You have about a <50% chance the fault will be fixed. If not then the ethanol has done no further harm but has not helped.

Interesting. Thx Bryn!