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Thread: Humidity sensor/Humidistat

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    Humidity sensor/Humidistat

    Afternoon all,

    I've been toying with ideas on how to use my breakout box for a melee of applications; One of which is the possibility of using a preset humidity sensor. I've seen a few of these devices that run on 3v with an output signal (probably to a display/cpu). Is this possible?

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    Master Control Freak RussM's Avatar
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    If the sensor has a dry contact NO or NC output, then it should work.
    Please do not send me PMs with technical questions or requesting assistance - use the forums for Apex help. PM me ONLY if the matter is of a private or personal nature. Thanks.

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    Quote Originally Posted by RussM View Post
    If the sensor has a dry contact NO or NC output, then it should work.
    NO/NC output? (I have absolutely no idea). I've been looking at a few on ebay:

    http://www.ebay.co.uk/itm/Black-DHT1...IAAOSwXeJYKJba

    My thoughts are if these can be preprogrammed to become 'active' at a certain humidity then logic says that you should be able to use the 3v and gnd.

  4. #4
    Master Control Freak RussM's Avatar
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    That will not work. You cannot use a device which outputs a voltage to the BoB.

    You need one that has a switch inside which simply opens and closes.

    NC = normally closed. NO = normally open
    Please do not send me PMs with technical questions or requesting assistance - use the forums for Apex help. PM me ONLY if the matter is of a private or personal nature. Thanks.

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    Frequent Contributor zombie's Avatar
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    Sometimes these are also labeled as SPST humistats. Basically if you see the words dry contact, NO, NC, SPST, SPDT, or DPDT in the product description it should work fine.

    You might be an engineer if...You have no life and can prove it mathematically.

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    So how sensitive might they be? The slightest indication of moisture?


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    Frequent Contributor zombie's Avatar
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    Quote Originally Posted by SNP View Post
    So how sensitive might they be? The slightest indication of moisture?


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    I would get one with a dial or digital display so you can set it to a level that works for whatever your application is. They're usually in the 5% hysteresis range for analog and 2% for digital.

    You might be an engineer if...You have no life and can prove it mathematically.

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    Ah ha! I have found one!!!!


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    H8908B (Honeywell Humidistat)


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    Frequent Contributor zombie's Avatar
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    That will work. When you program remember that CLOSED is below target humidity and OPEN is above target humidity.

    You might be an engineer if...You have no life and can prove it mathematically.

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