Recently a variety of remote-controlled light bulbs have entered the market at various price points. Soon they were followed by products that imitated most of the functions (such as power and changing colour) however with much more inexpensive technology. One example of these are bulbs controlled by RF data links. These are very useful to the hacking and maker community, as the RF signal can easily be determine and replicated by an Arduino.
This exact process has been demonstrated by Instructables user FabricateIO who uses a cheap bulb from Amazon, and determines the required signals to control the bulb using some open-source test equipment. They explain how to dump the contents of the bulb's EEPROM which contains the codes required to activate it - and with a little detective work you can then have an Arduino and RF transmitted reproduce the codes - and thus have much better control of the bulbs - as demonstrated in the following video:
Another example of how you can command inexpensive consumer devices with an Arduino. To get started, check out the project page. And for more, we're on facebook, Google+, and twitter - so follow us for news and product updates as well.
If you're looking to learn about Arduino development platform and how it interacts with external devices, you can't go past "Arduino Workshop - A Hands-On Introduction with 65 Projects” by John Boxall.
Arduino Workshop takes the reader from having zero knowledge about the Arduino platform, electronics and programming and leaves them with the know-how and instructions on everything from blinking an LED, to robotics, wireless data, cellular communications, motor control, sensors, Internet connected systems and more. For more information including a sample chapter and table of contents, visit the book page.