Arduino is an open source microcontroller, which can be used to control electronics remotely. It consists of an arduino board, which is programmed using a language similar to C++, and receives data input from different sensors. These sensors include lights and motors, for example. The software that works with arduino is based on Processing, which is also open source. An example of how an arduino board can be used is using a light sensor to switch a lightbulb on an off. If it is dark, it could be programmed to switch the lightbulb on, and if it is light, the lightbulb could be switched off. The arduino board would be the part that actually senses the data (in this case, the amount of light), and the values can be inserted into code in Processing to control when the bulb is switched on and off.