Is there anyone can provide me info. on how to make a thermometer using
P.S. By the way, can anybody suggest where to obtain spec. of I2C bus?
Ming Tak Eric Chan________________________
Happiness is like the bluebird of Maeterlinck:
try to catch it and it loses its colour. It's
just like holding water in your hands. The
more you squeeze it the more it runs away.
> Is there anyone can provide me info. on how to make a thermometer using
What are your constraints? Easy programming? Cost? Temperature range? High
precision? Here are just a few ideas...
Easy programming - how about hanging an LM35 sensor and a cheap op-amp onto
the analog input of a 16C6xx
Low cost - use a thermistor and a 7555 or similar to make a temperature
dependent oscillator. Calibrate this in software.
Wide temperature range - use a type-K thermocouple and a AD595 cold junction
compensator/amplifier. Feed this into a 12 bit a-to-d with a serial interface.
High Precision - Use a platinum resistance thermometer and a commercial
linearisation module (or design your own if you feel brave) Feed this into a
16 bit a-to-d with a serial interface.
I hope these are some help,
Keith Dowsett "Variables won't; constants aren't."
Snail mail: MRC Clinical Sciences Centre, Cyclotron Unit.
Hammersmith Hospital. London W12 0NN.
Mark K Sullivan
The PIC14000 has an *internal* temperature sensor it can digitize to 16 bits.
- Mark Sullivan -
Dana Frank Raymond
>Is there anyone can provide me info. on how to make a thermometer using PIC?
Well, you need a temperature sensor and some method of output. A thermostat
may have outputs to control temperature to either a fixed or variable setpoint.
An example of a temperature sensor can be found in application note AN512.
Its available in the Embedded Control Handbook and on http://www.microchip.com
Regards, Dana Frank Raymond
I'm currently developing one using a thermistor I bought at Radio Shack. It
works great, and I've got it displaying on three 7-Segment LED Displays.
The only problem is with the calibration. I have a scheme for it that
works, but I'm having some problems with writing to the EEPROM (to save the
More as it happens,
Do you ever feel like an XT Clone caught in the Pentium Pro Zone?
if you can't solve the curve-fitting then use a ds1820
as soon as I finish my soft for it I can send it to you
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