* connect a DS18B20 temperature sensor to an arduino
* read from the sensor using the 1-wire interface
* send that data to xively.com directly from the arduino
* view the resulting graph on the internet
http://xively.com is an Internet of Things host that generates graphs based on data you provide. In this example I am going to use it to monitor the temperature in my room. It's not a hackerspace, my wife keeps it far too tidy for that.
Step 1: Parts list
I have an arduino Uno clone and a wiznet 5100 shield.
* Power supply (it can be powered via the USB port)
I was fortunate that my router has USB ports that provide the 5v output meaning the arduino is powered whenever the router is and saves a plug, electricity, the environment and the future of the world.
* DS18B20 temperature sensor
* RJ45 network cable connected between the arduino and your router