At 09:35 PM 5/20/2008, you wrote:
>I need a low cost (in qty) way to sense room temperature.  I tagged this
>as [PIC] as I'm looking for a solution which is low-cost when
>considering interfacing to the PIC processor.
>
>Right now I'm bit banging a DS18S20 (had a library) on a PIC18F part for
>development purposes, but this is a bit pricey and sometimes hard to find.
>
>My goals are as follows:
>
>1) 3.3V (this is a biggy-it seems some of the more popular sensors need 5V+)
>
>2) Cheap and easily obtainable.  Mouser stocking it is a plus.
>
>3) No calibration required to obtain accuracy within a few degrees
>(solder and be done).
>
>4) Ok to use about any resource on the PIC.  I have ADC ins and spare
>I/O pins available.  The SPI interface is somewhat tied up with a couple
>of other devices which are fairly high-bandwidth, but I could do a SPI
>sensor if need be.  I2C not so much, although I guess I could bit-bang
>i2c as well.
>
>5) Through hole packaging.  No SMD-only parts.
>
>6) -40*F to well over 120*F.  The idea is to monitor likely temperature
>ranges for outdoor enclosures.
>
>Ideas?
>
>-forrest

Thermistor. Just like just about every consumer thermometer in the world,
probably billions by now.

Best regards,

Spehro Pefhany --"it's the network..."            "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com



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