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low cost humidity? — Parallax Forums

low cost humidity?

SSzretterSSzretter Posts: 4
edited 2008-07-14 18:03 in BASIC Stamp
Does anyone know of a low cost way to read humidity?

I know about the SHT11, etc. sensors, but they are like $30+ each.

Comments

  • FranklinFranklin Posts: 4,747
    edited 2008-07-14 15:21
    Define "low cost" .

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    - Stephen
  • SSzretterSSzretter Posts: 4
    edited 2008-07-14 16:26
    Well, to start with, less than $30.
    Ideally $10 (or less) would be great...
  • FranklinFranklin Posts: 4,747
    edited 2008-07-14 17:01
    Best price I found for an HIH-4000-001 was $21 at DigiKey but then you would need other parts to connect it to the stamp. I'd go with the SHT11.

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    - Stephen
  • Tracy AllenTracy Allen Posts: 6,664
    edited 2008-07-14 18:03
    If you look at the Newark.com, there are humidity sensors ranging from less than $5 up to $100. Lower cost as a general rule also means lower accuracy and shorter useful life, and/or additional excitation and readout circuitry. The $5 sensor is basically a little capacitor that changes capacitance with humidity, and it would require a 555 oscillator circuit, and also a temperature measurement and math for compensation, and would have to be calibrated. It might be great for what you want to do, but you really do get a lot for the $30 price of the Sensirion.

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    Tracy Allen
    www.emesystems.com
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