Selecting Temperature sensor IC

Discussion in 'The Projects Forum' started by sam_kevin, Jan 21, 2013.

  1. sam_kevin

    Thread Starter New Member

    Jan 21, 2013
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    Hi, Could some one help me out in selecting a temperature sensor IC for my project.

    I need to sense the temperature of the refrigerator which will drop to minus 30 deg Celsius, say the sensing range should be -30 to +40 deg Celsius.

    The device that I am using has only one ADC pin, and the distance between my sensor and the device will be about 10meters long, Kindly suggest me sensor IC or guide me how to overcome the wire resistance as the wire length is 10Meters. the accuracy can be +- 2%.

    I am new to electronics I am wishing to do this project by my own, Kindly guide me with better solutions. Thank you

    Yours faithfully
    Sam.
     
  2. MrChips

    Moderator

    Oct 2, 2009
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  3. spinnaker

    AAC Fanatic!

    Oct 29, 2009
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    I like the Dallas One Wire devices Mr. Chips pointed out. Initially harder to use software wise but once you get the chips talking, very easy and flexible to use.
     
  4. wayneh

    Expert

    Sep 9, 2010
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    Depending on what you're doing, the LM35 offers the advantage of using any old cheap voltmeter as your display. No need to build your own display. You can be up and running within minutes of the LM35 arriving.
     
  5. sam_kevin

    Thread Starter New Member

    Jan 21, 2013
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    Thanks for your suggestions, but i can't use LM35, as my GSM device cant read minus voltage in minus degree and i can't use one wire device to coz i cant program my GSM module.
     
  6. wayneh

    Expert

    Sep 9, 2010
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    What's a GSM device?
    You might be able to offset the grounds by a known voltage, so that the LM35 virtual ground is above the ground of your "GSM".
     
  7. sam_kevin

    Thread Starter New Member

    Jan 21, 2013
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    WAyneh The problem with LM35 IC is that, accuracy below minus 11 deg cel. is to low, and it will not work for long distance wire.
     
  8. wayneh

    Expert

    Sep 9, 2010
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    You said you needed 2% accuracy down to -30°C, which the LM35 is guaranteed to exceed. And using a 10m cable is not at all unusual for these. Why do you think it wouldn't work?
     
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