Book Image

Mastering Internet of Things

By : Peter Waher
Book Image

Mastering Internet of Things

By: Peter Waher

Overview of this book

The Internet of Things (IoT) is the fastest growing technology market. Industries are embracing IoT technologies to improve operational expenses, product life, and people's well-being. Mastering Internet of Things starts by presenting IoT fundamentals and the smart city. You will learn the important technologies and protocols that are used for the Internet of Things, their features, corresponding security implications, and practical examples on how to use them. This book focuses on creating applications and services for the Internet of Things. Further, you will learn to create applications and services for the Internet of Things. You will be discover various interesting projects and understand how to publish sensor data, control devices, and react to asynchronous events using the XMPP protocol. The book also introduces chat, to interact with your devices. You will learn how to automate your tasks by using Internet of Things Service Platforms as the base for an application. You will understand the subject of privacy, requirements they should be familiar with, and how to avoid violating any of the important new regulations being introduced. At the end of the book, you will have mastered creating open, interoperable and secure networks of things, protecting the privacy and integrity of your users and their information.
Table of Contents (24 chapters)
Title Page
Copyright and Credits
Dedication
Packt Upsell
Contributors
Preface
Index

Plotting graphs


No sensor application is complete without plotting graphs. We can do this directly from the web interface hosted on the sensor itself. We have already defined a web page for it: /History.md. We first need to add the Waher.Script.Graphs NuGet package to the project. It adds graph plotting functions to our scripting engine. It uses the cross-platform SkiaSharp two-dimensional drawing package to do the actual drawing. We must just make sure to add the corresponding assemblies of Waher.Script and Waher.Script.Graphs to the types inventory when we initialize the application.

Note

For a list of script syntax supported, including some extension libraries, see http://waher.se/Script.md.

Reading historical values from the database

To plot historical values, we first need to read them from the database. We can use the Find<T>() method on the static Database class to find, filter, and sort objects in the database. It returns an enumerable set of objects of type T (IEnumerable<T...