Earlier I presented a project on how to measure temperature with a LM35 and an Atmega8 microcontroller and display it on LCD. In the current project an Arduino board is used and the temperature reading is sent to a PC. A software is written for PC to display the data received on USB from the Arduino. It shows temperature value both in Celsius and Fahrenheit, numerical and as a bar-graph and a histogram with 100 data points.
The sensor is connected to one of the analog inputs of the Arduino. The code for microcontroller is very simple since all it does is convert the analog output of the sensor to digital and send it to PC and it does that every second.
The PC software is written in Processing, all code is available in the link.
Arduino Thermometer: [Link]