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)

Control systems


A thermostat, as well as the system you are about to implement is an example of a control system. Simply put, a control system is a system that, based on a number of inputs, continuously decides on a value for one or more outputs. Most control systems are closed loop control systems (also known as feedback control systems), meaning that their outputs also influence the inputs, providing the system with feedback about the decisions it makes.

In this case, the inputs are the current temperatures and the setpoint temperature, and the single output is whether the heating system should be on or off. The feedback happens when the temperature changes due to the heating being on or off.

A lot of different sorts of control systems have been designed and documented but, like most on/off thermostats, this example will use a simple hysteresis controller. Consider the following approach: If any rooms have a temperature below the setpoint, turn the heating on; if all rooms are above the...