I was wondering if anyone had the circuitry to build a digital thermometer with an LED readout. Your help would be much appreciated!

 

Use Dallas DS1821, digital 1-wire thermostat temperature sensor along with PIC or any other microcontroller. DS1821 is a good sensor with +-0.5 degree celcius resolution.
Here you can find some source and schematic of DS1821
http://www.microchipc.com/sourcecode/#ds1821

Here is a schematic for DS1820 which is only temp. sensor (no thermostat). But you can implement your own thermostat in firmware.
http://www.anotherurl.com/therm/schematic.htm

Couple more schematics.....
http://chaokhun.kmitl.ac.th/~kswichi...avrthermo.html
http://users.senet.com.au/~wpeacock/avr/tempavr.html

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Thanks alot for that. We'll see how it goes.

Just one question,
Where do you obtain your circuit designs from or do you basically make them up as you go?

 

A bit of both, really. Often I take snippets of schematics, and put them together (like Java Beans, if you're into programming). There are also a lot of circuit encyclopaedias available at most libraries, and quite a few good circuit sites on the web.

As for the LED readout for your thermometer - have a look at the LM3914 - it seems to be popular lately It's an LED bargraph driver.