(13-06-2021, 16:31)Werk_AG Wrote: There should be a reason why brands like Davis, Purple Air and others don't put the T/H sensor outside the box or even too exposed...
I will take this as humour.
My 60 year old brain is still thinking.
1/ You warned me that the AQM 3D box is not waterproof and should be installed under a porch for example.
2/ Unless I am mistaken, the ideal solution for the positioning of the T/HUM sensor is before the PM sensor in its air circuit.
3/ The PurpleAir suffers from a reliability problem because the PMS sucks in water drops (Look at the positioning of the PMS in relation to the lower horizontal plane of the box).
For information I slightly transformed mine with a grid that lowers the lower horizontal plane. I have repaired PurpleAir twice for acquaintances, the condition of the PMS was pitiful. By the way I'll have to open mine, the HUM sensor is probably dead.
4/ The Davis comes with a removable case, significantly lowering the horizontal plane.
If one has several PCBs, the solution considered to have good measurements and limit the risk of reliability (In Portugal humidity is problematic in some areas).
I take an IP55/56 enclosure to house the PCBs, power supply, etc...
I place the PMS/SPS/SDS sensors on the lower horizontal plane so that they suck in the outside air (with air guides: hole/funnel) I had posted an example, I think.
Just below my holes/air guides, I place the BMEs in a shield like the example above. And I put a Davis style cover to cover it all.
So, I have PCBs in the cover, AQI sensors sucking in outside air that has been measured by the BMEs 5 cm below in the same chamber where the AQI sensors are sucking.
My mini shelter protects the BMEs from external aggressions (rain, dust, insects, ...), and my additional cover ("Davis") prevents the BMEs from being under solar radiation.
It is the same solution as "Davis" but adapted to several PCBs and to the context of my environment.
This solution is most probably open to criticism, I am open to discussion.