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    Date: Sat, 27 Nov 1999  06:27:48
    From: "Nikolai Golovchenko" 
      To: "pic microcontroller discussion list" 
 Subject: Re:      Ambient Temperature sensing (cheaply)?
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>Hi All,
>
>I wish to include a temperature sensor on a small board that I am
designing.
>I am using a 16f877 so the input is easy. What i need to know is what
>temperature sensing device is needed for the range of 0 deg C. to 50 deg C.
>or there abouts. The simpler the better is possible. I have never attempted
>temp sensing B4.
>
>
>Thanks All
>
>Mathew Cohen.

You may also consider using Watchdog Timer as a temperature sensor. Its
frequency changes linearly over temperature, so it's possible to build a
termometer without external chip!  See AN720. They claim temperature
accuracy up to 1 degree Celsius. I wish to test it sometime.

Regards.
_

Nikolai Golovchenko, Electrical Engineering Student
National Mining University of Ukraine www.nmuu.dp.ua
Dnepropetrovsk, Ukraine
E-mail: golovchenko@mail.ru