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Thermistor interface? — Parallax Forums

Thermistor interface?

ArchiverArchiver Posts: 46,084
edited 2004-01-30 00:38 in General Discussion
Does anyone know of a thermistor interface to a Stamp? I'd like to
measure temperature over a wider range than the thermocouple provides.
I want to track "degree-days".

Russ

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2004-01-29 23:43
    Hi Russ,

    A thermistor is just a resitor which varies with temperature. You can
    use the RCTIME command to find the resistance the of the thermistor
    and from there you can calculate temperature.

    Most thermistors (NTC) are have a non-linear characteristic. If you
    draw the values of resistance versus temperature you get a curve, not
    a straight line.

    Some thermistors come with a kind of datasheet where resitance and
    temperature are listed. From there you can contruct a lookup table to
    calculate temperature.

    It takes some time and thinking but it works.

    Regards,

    Klaus

    --- In basicstamps@yahoogroups.com, "russranshaw" <home.rr@c...>
    wrote:
    > Does anyone know of a thermistor interface to a Stamp? I'd like to
    > measure temperature over a wider range than the thermocouple
    provides.
    > I want to track "degree-days".
    >
    > Russ
  • ArchiverArchiver Posts: 46,084
    edited 2004-01-30 00:01
    THERE IS AN IbUTTON THERMISTER THAT HAS A BUILT IN
    DATALOGGER. yOU CAN SET IT TO GO OFF AS OFTEN AS YOU WANT. i
    THINK IT WILL STORE 2048 SAMPLES

    Sorry, had the caps on.

    ---- Original message ----
    >Date: Thu, 29 Jan 2004 21:31:32 -0000
    >From: "russranshaw" <home.rr@c...>
    >Subject: [noparse][[/noparse]basicstamps] Thermistor interface?
    >To: basicstamps@yahoogroups.com
    >
    >Does anyone know of a thermistor interface to a Stamp? I'd
    like to
    >measure temperature over a wider range than the
    thermocouple provides.
    > I want to track "degree-days".
    >
    >Russ
    >
    >
    >
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    --
    Regards

    Dave Evartt
    American Hovercraft
  • ArchiverArchiver Posts: 46,084
    edited 2004-01-30 00:38
    Look at the BS1 app notes. One of them describes
    such a beast.

    regards, Jack

    > Does anyone know of a thermistor interface to a Stamp? I'd like to
    > measure temperature over a wider range than the thermocouple provides.
    > I want to track "degree-days".
    >
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