element14 Community
element14 Community
    Register Log In
  • Site
  • Search
  • Log In Register
  • Community Hub
    Community Hub
    • What's New on element14
    • Feedback and Support
    • Benefits of Membership
    • Personal Blogs
    • Members Area
    • Achievement Levels
  • Learn
    Learn
    • Ask an Expert
    • eBooks
    • element14 presents
    • Learning Center
    • Tech Spotlight
    • STEM Academy
    • Webinars, Training and Events
    • Learning Groups
  • Technologies
    Technologies
    • 3D Printing
    • FPGA
    • Industrial Automation
    • Internet of Things
    • Power & Energy
    • Sensors
    • Technology Groups
  • Challenges & Projects
    Challenges & Projects
    • Design Challenges
    • element14 presents Projects
    • Project14
    • Arduino Projects
    • Raspberry Pi Projects
    • Project Groups
  • Products
    Products
    • Arduino
    • Avnet & Tria Boards Community
    • Dev Tools
    • Manufacturers
    • Multicomp Pro
    • Product Groups
    • Raspberry Pi
    • RoadTests & Reviews
  • About Us
  • Store
    Store
    • Visit Your Store
    • Choose another store...
      • Europe
      •  Austria (German)
      •  Belgium (Dutch, French)
      •  Bulgaria (Bulgarian)
      •  Czech Republic (Czech)
      •  Denmark (Danish)
      •  Estonia (Estonian)
      •  Finland (Finnish)
      •  France (French)
      •  Germany (German)
      •  Hungary (Hungarian)
      •  Ireland
      •  Israel
      •  Italy (Italian)
      •  Latvia (Latvian)
      •  
      •  Lithuania (Lithuanian)
      •  Netherlands (Dutch)
      •  Norway (Norwegian)
      •  Poland (Polish)
      •  Portugal (Portuguese)
      •  Romania (Romanian)
      •  Russia (Russian)
      •  Slovakia (Slovak)
      •  Slovenia (Slovenian)
      •  Spain (Spanish)
      •  Sweden (Swedish)
      •  Switzerland(German, French)
      •  Turkey (Turkish)
      •  United Kingdom
      • Asia Pacific
      •  Australia
      •  China
      •  Hong Kong
      •  India
      • Japan
      •  Korea (Korean)
      •  Malaysia
      •  New Zealand
      •  Philippines
      •  Singapore
      •  Taiwan
      •  Thailand (Thai)
      • Vietnam
      • Americas
      •  Brazil (Portuguese)
      •  Canada
      •  Mexico (Spanish)
      •  United States
      Can't find the country/region you're looking for? Visit our export site or find a local distributor.
  • Translate
  • Profile
  • Settings
Arduino
  • Products
  • More
Arduino
Arduino Forum weather sensor help!?!
  • Blog
  • Forum
  • Documents
  • Quiz
  • Events
  • Polls
  • Files
  • Members
  • Mentions
  • Sub-Groups
  • Tags
  • More
  • Cancel
  • New
Join Arduino to participate - click to join for free!
Actions
  • Share
  • More
  • Cancel
Forum Thread Details
  • State Suggested Answer
  • Replies 12 replies
  • Answers 1 answer
  • Subscribers 404 subscribers
  • Views 1106 views
  • Users 0 members are here
  • outdoor
  • humidity
  • weather
  • sensor
Related

weather sensor help!?!

funinalaska
funinalaska over 12 years ago

Does anyone know of a outdoor humidity sensor that works in extremely cold temps?

I need something that is moisture save and that will work at temperatures well below -40

I need it to have a minimum 2M watertight lead.

Right now for temperature I am using the DS18B20

It works for temperature but have now discovered I also need humidity readings as well.

  • Sign in to reply
  • Cancel
Parents
  • Former Member
    0 Former Member over 12 years ago

    Hope this helps finding a solution.

    .

    Just keep in mind that RH stand for relative humidity. If the water in the air (humidity) freeze the RH = 0% in any case. Thus the sensor must just survive the extreme cold condition while RH will be 0%.

      There is also a method of reading RH with a wet and dry temperature sensor if you find it difficult finding a RH sensor to survive the extreme cold condition. Formula for this calculation should be available on the net.

    • Cancel
    • Vote Up 0 Vote Down
    • Sign in to reply
    • Verify Answer
    • Cancel
  • Former Member
    0 Former Member over 12 years ago in reply to Former Member

    O

    The last method mentioned (wet dry). I found more reliable and durable. The capacitive sensors tend to hold up better but need to be re-calibrated from time to time. I have done incubation controllers in the past and experience extreme pain on RH sensors. Land me eventually on the wet dry method.

      But in incubation: By controlling the temperature (dry reading) is held stable there for the RH control were not too difficult and controlled the RH with a fixed offset from “temperature reading (dry reading)” by using the wet reading.

    • Cancel
    • Vote Up 0 Vote Down
    • Sign in to reply
    • Verify Answer
    • Cancel
  • kas.lewis
    0 kas.lewis over 12 years ago in reply to Former Member

    bensmith can you provide a link to this method as it does sound interesting.

     

    Thanks

    • Cancel
    • Vote Up 0 Vote Down
    • Sign in to reply
    • Verify Answer
    • Cancel
Reply
  • kas.lewis
    0 kas.lewis over 12 years ago in reply to Former Member

    bensmith can you provide a link to this method as it does sound interesting.

     

    Thanks

    • Cancel
    • Vote Up 0 Vote Down
    • Sign in to reply
    • Verify Answer
    • Cancel
Children
  • Former Member
    0 Former Member over 12 years ago in reply to kas.lewis

    It has been some time ago that I have done Incubation using RH measurements (1995).

     

    Some links to explain what I were explaining.

    From Wikipedia Relative humidity - Wikipedia, the free encyclopedia.

    and Hygrometer - Wikipedia, the free encyclopedia . On this page the Wet Dry is explained. The "Hair tension hygrometers" on this page is most probable the one used at your airport.

    A technical doc http://www.vaisala.com/Vaisala%20Documents/Application%20notes/Humidity_Conversion_Formulas_B210973EN-F.pdf

    Above a bit too intensive for this discussion but any case it is there to read.

     

    To keep it simple. For a weather station use a simple curve fit formula to follow the chart at where the WS is situated to obtain the RH value from Wet/Dry. Psychrometrics - Wikipedia, the free encyclopedia

    Or just table the values in 5% or 10% increments and linear calculate the RH between 2 points will have an accuracy 2-3%RH (well suited for a WS +-5%RH)

    Keep in mind if you are in a 1%RH accuracy I deem it extremely accurate. For to find an instrument in less than 1%RH is very expensive and need to be calibrated with buffers before use every time.

     

    Else

    Look at SiLabs IC's Si7013/20/21 Humidity Sensors | Silicon Labs

    -40C to +125C operating.

    main page is Humidity and Temperature Sensor ICs | Silicon Labs

    I always had a good reliability experience from SiLabs components.

    • Cancel
    • Vote Up 0 Vote Down
    • Sign in to reply
    • Verify Answer
    • Cancel
element14 Community

element14 is the first online community specifically for engineers. Connect with your peers and get expert answers to your questions.

  • Members
  • Learn
  • Technologies
  • Challenges & Projects
  • Products
  • Store
  • About Us
  • Feedback & Support
  • FAQs
  • Terms of Use
  • Privacy Policy
  • Legal and Copyright Notices
  • Sitemap
  • Cookies

An Avnet Company © 2025 Premier Farnell Limited. All Rights Reserved.

Premier Farnell Ltd, registered in England and Wales (no 00876412), registered office: Farnell House, Forge Lane, Leeds LS12 2NE.

ICP 备案号 10220084.

Follow element14

  • X
  • Facebook
  • linkedin
  • YouTube