Preface

Just a few decades back, the average computer was the size of an entire city block and could barely store 5 MB of data. Today, this amount of data is consumed by an average image upload, and the dimensions of the modern computer have reached a stage where we can hold one on the palm of our hands. Alongside the reduction in size, computers have also undergone a tremendous reduction in cost. Raspberry Pi is the flag bearer of portable and affordable computing, barely costing $30 and being small enough to be held in your hand.

The introduction of Raspberry Pi has opened the doors for applications that would not have been feasible otherwise, and that is precisely what you will learn from this book.

In the chapters to follow, you will learn how Raspberry Pi can be utilized to its full potential and act as a sensor interface, a web server, and a database and host all the components of a fully functioning web application. You will also learn how to utilize cloud-based APIs and data storage and combine this with the existing components developed on Raspberry Pi to make an application that can accessed by anyone with an internet connection.

What this book covers

Chapter 1, Getting Started on the Raspberry Pi , takes a brief look at Raspberry Pi, its OS, and how to get started using it

Chapter 2, Getting Up-and-Running with Web Development on the Raspberry Pi, covers a high-level overview of the project that we will build and the different components of its technology stack.

Chapter 3, Running a Node Server on the Pi, helps you get started with Node.js, its installation on the Pi, and how to get up and running with Node.js by running a web server on the Pi.

Chapter 4, Extracting Information from the GPIO Pins, introduces you to the DHT22 sensor and demonstrates how to get information about the temperature and humidity recorded from the sensor.

Chapter 5, Retrieving Sensor Readings from the Server, goes through how to make the sensor readings available to the node server that was made earlier. By the end of this chapter, you will know how to make sensor readings available through a REST API.

Chapter 6, Creating a Web Page to Display Sensor Data, gets you started with your UI development journey by developing a webpage that will make use of the API created in the previous chapter to display the data received from the sensor in a user-friendly webpage.

Chapter 7, Enhancing Our UI - Using Interactive Charts, covers how to make an even richer user interface through the use of charts. This will be achieved through the use of open source chart libraries

Chapter 8, SQLite - The Fast and Portable Database, covers the basic concepts of the SQLite database and teaches you how to install and run it on your Pi.

Chapter 9, Integrating SQLite into Our Application, explains how to upgrade our existing application built in the previous chapters by persisting our data.

Chapter 10, Making Our Application Real Time with Web Sockets, discusses how all this time, the only way for our HTML5 frontend to get data from the server was through polling and making requests at regular intervals. Web sockets allow us to establish a connection only once, after which the server can actually push data to the browser.

Chapter 11, Deploying Our Application to Firebase, reiterates that our entire application is currently hosted on the Raspberry Pi. This works, but is not very scalable. This chapter will go through how to host our UI and database on Google's Firebase cloud architecture.

Chapter 12, Using Firebase APIs to Update Our Application, covers how to update the database by calling Firebase's cloud APIs from Raspberry Pi so that the cloud hosted application can get a continuous feed of the readings on the Pi.

What you need for this book

The reader should have some basic knowledge and programming experience (in any programming language). An awareness of the basic concepts regarding HTML and JavaScript would be a plus point, but is not required, and of will be covered in brief in this book. The reader is also expected to have a base level understanding of electronic hardware (how to connect pins and wires).

To execute all the examples given in this book, you will need the following:

• A Raspberry Pi board, which will be the device where all the code is executed
• Monitor, keyboard, and mouse to interact with the Raspbian OS
• Memory card for the Raspberry Pi
• Personal computer (optional), although this book is designed such that the entire application can be built and executed on the Pi, having a computer handy can help a lot.

Who this book is for

This book is aimed at hobbyist, enthusiasts, and developers eager to develop embedded device-powered web applications. Prior programming experience with JavaScript, HTML5, and Node.js will be beneficial.

Conventions

In this book, you will find a number of text styles that distinguish between different kinds of information. Here are some examples of these styles and an explanation of their meaning. Code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles are shown as follows: "Most of these files have no meaning to us except the INSTRUCTIONS-README.txt file."

A block of code is set as follows:

     app.get('/temperature', function(req, res) {
     res.send('24 °C');
     });

Any command-line input or output is written as follows:

firebase --version

New terms and important words are shown in bold. Words that you see on the screen, for example, in menus or dialog boxes, appear in the text like this: "In the Firebase console, go to the SERVICE ACCOUNTS section of your application settings."

Warnings or important notes appear like this.

Tips and tricks appear like this.

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