Being able to control power points (outlets/GPOs depending on where you hail from) remotely with a smartphone or other device is a very useful thing to have, however the project can often be hampered by not wanting to work with mains current. One popular method of getting around this is to use the inexpensive wireless power points that are controlled with inexpensive wireless data transmitters, and a great method of doing so has been documented by Stephen Arthur.
In his version, an Ethernet-enabled Arduino board is connected to an inexpensive wireless data transmitter that matches the frequency of the receiver in the wireless power points. Then they can be controlled over the LAN with URL commands - and to simplify this Stephen has written an Android app for his device to create a neat GUI, as shown in the following video:
Finally he explains how to use a simple logic analyser to determine the wireless protocols used by these inexpensive wireless modules to you can hack your own. Great stuff - so visit his website to learn more and for all the code. And for more, we're on twitter and Google+, so follow us for news and product updates as well.
If you need an Ethernet-enabled Arduino, save time, space and money by using the Freetronics EtherTen. Apart from being fully Arduino Uno-compatible, it has onboard Ethernet, microSD socket, full USB interface (so you don't need a costly FTDI cable just to upload a sketch!) and supports optional Power-over-Ethernet.