DIY temp sensor

so i searched through the forums, but i really couldnt find anything in a diy form.

so im wondering, what would i need to do a serial temperature sensor. id be happy with one temp sensor, but more would be nice.

any ideas? just looking for a cheep diy project. dont want to spend money on something that i could build myself cheeper.

thanks
-Sean

Take a look here this may be of use to you,

http://www.iguanalabs.com/tempture.htm
or
http://www.qkits.com/serv/qkits/diy/pages/QK145.asp

http://www.electronics-lab.com/projects/pc/010/

hey, thanks, that will at least give me a start. the middle one looks like a pretty good option, and its not bad for that price.

maybe ill just have to bite the bullet and pay money :(

thanks for the reply.

You could use a thermistor as a simple temperature sensor because its resistance changes with temperature, then build a circuit around it

Even the "second one" costs quite a bit of money ($25 just for the circuit board you plug the sensors into)...then you gotta buy a serial cable, 4 sensors (& wire em up too)...by the time you do that, you're talkin $50.

The item I looked at was the "Digital Doc 5+". It has 8 temperature sensors, allows for running 8 fans (no speed control, just on/off)...and runs on 12v. The newer model has usb support, but that's something I don't need as I wasn't plannin on usin it in the carputer anyway, more as a dashmounted digital temp display/fancontroller. And that's $59.

How about building one of these? http://www.discovercircuits.com/S/s-temperature.htm