ATtiny Hacks: Simple USB temperature probe
 

Based off a similar temperature monitoring example called EasyLogger, his temperature probe uses an LM34 temperature sensor, which is wired to an ATtiny45. The ATtiny communicates with his computer using the Ruby-USB library in conjunction with a bit of Ruby code he put together. Once the data is obtained, all of the temperature measurements are logged and graphed using RubyRRDTool.

http://hackaday.com/2011/09/17/attin...8Hack+a+Day%29