What is this pin for?

[nevermore3d]

What is this pin for?

[0ndsk4]

Yes. Both are not needed tho, most would do a dual sensor stack using a single mounting hole. Saves on wiring.

[0ndsk4]

It’s a spacer for when stacking the VOC sensors. Makes it a bit more stable.

[SarcasmRules]

Thx, much appreciated.
One more question, there are 2 of each sensors on the BOM but only one of each is in the CAD, assuming both are intake. In the controller section by SanaaHamel there is an intake and exhaust sensor(s); where are the other two installed?

[0ndsk4]

There are two sensor pairs. A BME280 and a SGP40 are stacked on top of each other - one pair at the intake (flow chamber), one pair at the exhaust (center hub next to the pico).

[SarcasmRules]

That's what I was missing, thanks! :) I'm printing one up, have the flow and main chamber done, printing the basket now.
It looks nice but way bigger than I thought (TWSS!).

[mrzottel]

So just to be sure - those two holes left and right of the pico are used for mounting the exhaust sensors?