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Need information on room temperature sensor.

Discussion in 'Embedded' started by Kelvin, Oct 18, 2004.

  1. Kelvin

    Kelvin Guest

    What I need is a minituare temperature sensor that can sense the room
    temperature between 10C to 40C, precision of up to 0.1C.

    Has anyone seen such information?

    Thanks.
     
    Kelvin, Oct 18, 2004
    #1
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  2. Kelvin

    s6sej73w9 Guest

    IC's can do that. googleit
     
    s6sej73w9, Oct 18, 2004
    #2
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  3. Dear Kelvin:

    Thermistors are ideal.

    David A. Smith
     
    N:dlzc D:aol T:com \(dlzc\), Oct 18, 2004
    #3
  4. Kelvin

    hamilton Guest

    Do you want a temperature "sensor" or a temperature "logger" ?

    A temperature is about the size of a peanut with wires coming out of it.

    A logger will measure the voltage across the sensor, that voltage is
    proportional too the temperature on it.

    Loggers come in lots of sizes and some are battery operated.
    Storage will store past samples in the hundreds or thousands of samples.

    The big question that a group like this would like to know is:

    Do you want to _buy_ or _build_ a temp logger ?
     
    hamilton, Oct 18, 2004
    #4
  5. Dallas do a little 8-pin thing, with I2C interface.

    There's also a 3-pin LM?35? give a voltage out proportional to temperature.
    (One variant has an offset to allow -ve temperatures)



    Aside: when the Americans say e.g. "thirty degrees below zero", as they
    use the Fahrenheit scale, where freezing point is 32 degrees, what do
    they mean by this: do they mean "30 degrees below freezing", or literally
    "-30 degrees F" (which is 62 deg below freezing) ?

    Richard [in PE12]
     
    Endymion Ponsonby-Withermoor III, Oct 18, 2004
    #5
  6. Kelvin

    Henry Kiefer Guest

    If price is not important, use the SMT160 - available in 3-pin transistor
    like package and in SO-8 SMD IC. Other forms also available.
    Precision is very good, better than 0,1 centigrade. Output is PWM. You can
    convert it to analog with a simple RC-filter.

    regards -
    Henry

    --

    <Schau auch mal auf meine Homepage www.ehydra.dyndns.info>
    <u.a. Versand von Wasserflohzuchtansatz, Wasserpflanzen/-schnecken,
    brasilianischer Sauerklee, Natron zum Backen/Baden, u.a.>
    <Alternativ über http://people.freenet.de/algenkocher>
     
    Henry Kiefer, Oct 18, 2004
    #6
  7. Kelvin

    Norm Dresner Guest

    "Endymion Ponsonby-Withermoor III"
    LM335 at National Semiconductor
    http://www.national.com/search/search.cgi/main?keywords=LM335

    Norm
     
    Norm Dresner, Oct 18, 2004
    #7
  8. Kelvin

    Norm Dresner Guest

    "Endymion Ponsonby-Withermoor III"
    This American means -30F when he says "thirty degrees below zero" in social
    conversations since that's the conventional temperature scale. I think that
    most Americans mean the same thing. So " ... " is, indeed, 62F below
    freezing.

    What I mean in engineering and scientific conversations depends on context.
     
    Norm Dresner, Oct 18, 2004
    #8
  9. Kelvin

    tadchem Guest

    Here in the U.S. the phrase "thirty degrees below zero" means exactly
    that, *below zero* - i.e. negative Fahrenheit temperatures (-30°F).
    Temperatures in the range 0°F to 32°F are simply referred to as
    "freezing" temperatures. A temperature of (plus) 30°F is "freezing"
    (or sometimes "below freezing") but not "below zero."

    Americans *are* rather slow to adapt. It could be worse, though.
    Engineers still use Roman Numerals in their reckoning.


    Tom Davidson
    Richmond, VA
     
    tadchem, Oct 18, 2004
    #9
  10. Kelvin

    CBFalconer Guest

    In this case the OP did specify "10C to 40C".

    Most general purpose band-gap voltage standard generators (which I
    believe includes the LM??? mentioned above) also deliver a signal
    proportional to temperature over some range. All the OP is likely
    to need is some form of A/D conversion for this essentially DC
    signal. The sensor will already supply both the signal and the
    reference voltage.
     
    CBFalconer, Oct 18, 2004
    #10
  11. Analog Devices: AD590
     
    richard miller, Oct 18, 2004
    #11
  12. If you want guaranteed 0.1°C interchangability and accuracy without
    calibration, even at a single point, let alone over that range, your
    choices are quite limited. A high precision thermistor will just do
    it, though with risk of drift.A high precision platinum RTD is the
    best solution if you really need that accuracy.


    Best regards,
    Spehro Pefhany
     
    Spehro Pefhany, Oct 18, 2004
    #12
  13. Either a thermocouple (probably K type) or a Pt100 sensor. Personnaly I
    feel more confident about the Pt100.

    --
    ********************************************************************
    Paul E. Bennett ....................<email://peb@a...>
    Forth based HIDECS Consultancy .....<http://www.amleth.demon.co.uk/>
    Mob: +44 (0)7811-639972 .........NOW AVAILABLE:- HIDECS COURSE......
    Tel: +44 (0)1235-811095 .... see http://www.feabhas.com for details.
    Going Forth Safely ..... EBA. www.electric-boat-association.org.uk..
    ********************************************************************
     
    Paul E. Bennett, Oct 18, 2004
    #13
  14. Further to my earlier posting you should contact this company. Where I am
    working at present bought a number of Pt100 sensors that are incredibly
    small, only cost about £13.00 and follow a very dependable
    temperature/resistance curve which is a BS/EN standard. You may find it
    easier to ask Morten himself about these devices as I do not think they are
    represented on his company's web-site. They operate on the basis of "tell
    us what sensors you need we will source them at a competitive price. He has
    helped us out with a number of unusual sensor requirements over the past
    couple of years.

    http://www.sensor-technik.co.uk/

    --
    ********************************************************************
    Paul E. Bennett ....................<email://peb@a...>
    Forth based HIDECS Consultancy .....<http://www.amleth.demon.co.uk/>
    Mob: +44 (0)7811-639972 .........NOW AVAILABLE:- HIDECS COURSE......
    Tel: +44 (0)1235-811095 .... see http://www.feabhas.com for details.
    Going Forth Safely ..... EBA. www.electric-boat-association.org.uk..
    ********************************************************************
     
    Paul E. Bennett, Oct 18, 2004
    #14
  15. Kelvin

    Martin Pot Guest

    The LM75 is a I2C thermostat and thermometer, -128 to 128 °C.
    Accuracy is a problem though, +/- 0.5 °C

    ---
    Martin Pot ()
    http://www.xs4all.nl/~pot

    Plutonium lasts twenty-five millennia, but arsenic is forever.
    - Terry Pratchett -
     
    Martin Pot, Oct 19, 2004
    #15
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