Spritzwasser-Schutz für Air-Rohr / Spray Protection for Outdoor Sensors

The old construction proposal from Luftdaten.info is the air tube, two knee elements made of 70mm PVC, pushed into each other. Not particularly attractive, but UV-resistant.

When it was unfortunately necessary to replace the temperature/humidity sensor again, I gave the thing a splash guard.

Consists of two parts: a solid ring with fine, slanted slats and a grille on the inside to prevent components from squeezing between the slats.

Together 20 mm high and 69 mm in diameter, the whole thing can be easily inserted and removed again with fine pliers when the sensor needs to be replaced.

Sensors:

• BME280: very sensitive to condensing moisture. Really good for air pressure.

• DHT21: Measured values deviate greatly from other sensors, especially for humidity.

• HTU21D: looks pretty good for now, we'll see.

• SDS011: has been working for years without any dropouts

Printing: goes quickly, especially if you keep the value for perimeter high and print the ring without infill. I printed it with 0.28mm, I'm usually too impatient for finer layers.

Then glue the two parts together so that the 'empty' part of the ring is covered by the grid.

Update:

I have added a third part, thermBlock. This can be pushed into the pipe between the MCU and the temperature sensor and it should better separate the sensor from the waste heat of the ESP8266. Whether it is necessary/useful remains to be seen. The old saying applies: *He who measures, measures crap.

FreeCAD sources are included, so customization is easy.

I have an air quality sensor which is housed in 2 PVC pieces, doesn't look good but is UV-resistant and since the sensor is outside at a place with some sun shine this is important. The temp/humidity sensors seem to be very sensitive against condensing humidity and this is something to protect the electronics against spray . It fits easily into the 70mm PVC housing.

After prining both parts glue them together such that the 'empty section of the ring is covered by the mesh (preventing parts of the electronics to work their way in between the lamellae of the larger part).

Update:

Added a third part, thermBlock which goes in between MCU and temperature sensor and is supposed to separate the sensor better against influence of the MCU's waste heat.

Update:

Tried a completly different approach to minimize the temperature errors: Stevenson Screen (https://www.thingiverse.com/thing:4907550)

FreeCAD-sources are included.

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