Book Image

Building Wireless Sensor Networks Using Arduino

By : Matthijs Kooijman
Book Image

Building Wireless Sensor Networks Using Arduino

By: Matthijs Kooijman

Overview of this book

Arduino has been established as the de facto standard microcontroller programming platform, being used for one-off do-it-yourself projects as well as prototypes for actual products. By providing a myriad of libraries, the Arduino community has made it very easy to interact with pretty much any piece of hardware out there. XBee offers a great range of low-power wireless solutions that are easy to work with, by taking all of the complexity of wireless (mesh) networking out of your hands and letting you focus on what to send without worrying about the how. Building wireless sensor networks is cost-effective as well as efficient as it will be done with Arduino support. The book starts with a brief introduction to various wireless protocols, concepts, and the XBee hardware that enables their use. Then the book expands to explain the Arduino boards to you, letting them read and send sensor data, collect that data centrally, and then even control your home from the Internet. Moving further more advanced topics such as interacting through the standard Zigbee Home Automation protocol, or making your application power-efficient are covered. By the end of the book, you will have all the tools needed to build complete, real-world solutions.
Table of Contents (8 chapters)

XBee power-saving


Typically, a radio is responsible for a big part of a device's current draw. Even though the XBee radio modules are designed to be low in power, their maximum power usage is typically in the 40-80 mA range while receiving. The XBee modules have the same current usage while transmitting, with the long range XBee PRO modules needing up to 500 mA.

Fortunately, all these modules can be put to sleep just like your microcontroller, bringing their power usage in or below the μA range (less than 1 μA for the XBee ZB modules).

Of course, when an XBee module is sleeping, it will be unable to receive any messages that are addressed to it. This creates a number of problems that need to be solved by the networking stack. In a ZigBee network, this is done by introducing a new class of devices called end devices (in addition to the coordinator and routers that you saw before), which are allowed to sleep.

To allow these end devices to sleep, some things work differently for them than what...