By now, you have created a real wireless sensor network, consisting of multiple nodes each containing some sensors and/or actuators that are controlled by a central coordinator.

However, all of your nodes have to be connected to the mains power, which limits the projects that you can build. You might not have a power outlet easily available everywhere and moving the nodes is cumbersome.

In this chapter, you will explore the various options for making your nodes battery-powered, allowing for a greater flexibility in deploying your projects and mobile or outdoor deployments.

Of course, battery power is not really useful if the battery is depleted in just hours or days. By applying the power saving techniques presented in this chapter, you will be able to let your nodes run for months or even years on a single battery charge.

In the first example, you will make the window sensor from Chapter 5, Standalone XBee Operation battery-powered. In addition to the components...