DH22 Sensor puzzle



  • I had ordered up a DH22 sensor with the intention of mounting it under a node case outside with the pins sticking into the case and sealed through with only the body exposed. I am perplexed by what was delivered in that the AM2302 expected (and shown on the website) is mounted on a PCB.
    Can anyone explain the purpose of this PCB?
    With my original mounting plan now scuppered as driven snow will undoubtedly short the pins, I presume this will have to be mounted in a vented tube or baffled in some way to allow airflow?

    0_1499253696685_WP_20170705_14_00_57_Pro[1].jpg


  • Hardware Contributor

    @zboblamont - The DHT22 needs a pull-up to work properly so my guess is that resistor 512 is that. 4,7k is the normal but 5.1k is close enough? The capacitor is probably just a input capacitor to make power more stable. Not necessary but doesnt hurt. PCB overkill? Yes, I think so. Looks like the PCB is coated though... maybe extra weather protection? Yes - I mount mine inside a vented (both sides) tube and that works great. If the space is to small or unvented it might pick up heat from the node.



  • @sundberg84 Thanks for that, so effectively the rest of the board is wasted space, presumably a board recycled from some other project. Very odd that the square area appears soldered on both sides of the pcb, purpose unknown....
    I that instance I may simply desolder the board and hope enough leg length survives to go back to plan A, putting supporting components where originally intended inside the case.
    The sun only hits that area toward late evening, the case is hard against a fence so would have to be near horizontal rain or snow to hit it.



  • @zboblamont It may be a board that they use for a few different sensors. They make these as boards with the necessary pull-up resistors and things to minimize the need for extra components when breadboarding a circuit for testing or other purposes. You could potentially unsolder the DHT22/AM2302 from the board if it didn't fit your design. You would just then have to remember to include the pull-up in your design.


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