The Open Iron is a open source soldering iron. At its heart there is an Arduino as the primary controller. All of the peripheral electronics are made in a modular system that is easy to repair and modify. This soldering iron has a ton of features.
A light sensor so that it turns off the soldering iron when the lights are turned off.
Real-time clock and SD card so that I can data log all of the soldering history. With this data there are a lot of possibilities such as predicting the life expectancy of the soldering tip.
There is a Spark Core module. There's a lot of potential with this module such as creating an iPhone app so you can monitor your soldering station. This way you can check to make sure you turned it off even after you left the house.
built-in fume extractor fan with speed control.
RGB LED on the handle that indicates the temperature reading by changing color.
Works with 120v and 240v because it uses a laptop style switching power supply.