Relay. Project Lab. Difficulty Level = 5 [What's this?]
UPDATE: I have re-done this project using simple 434MHz RF transmitter/receiver devices. Check out the new project!. UPDATE: Also see this project for an easy way to display a temperature reading: Digit Shield Temperature Display. I decided to explore the more advanced features of XBee radios by building a remote temperature sensor. Arduino Xbee, Zigbee wireless sensor and actuator iterface.
Xbee Adapter - wireless Arduino programming. If you have an Arduino project where the dev board is stuck inside a machine, or attached to the rafters or is inaccessable in some other way, a wireless programming/debugging link will save you tons of time. This tutorial is an extension on Rob's version. In this tutorial, no extra firmware or hardware (other than a capacitor) is necessary.
Just use the default bootloader.