Raspberry Pi Sensors

Rushi Gajjar

• Publisher: Packt Publishing
• Year: 2015
• ISBN:
  9781784393618
• Topic: Computer Science
• Subtopic: Computer Engineering
• Index: Computer Science

Raspberry Pi Sensors

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Table of Contents

Raspberry Pi Sensors

Credits

About the Author

Acknowledgements

About the Reviewers

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Free access for Packt account holders

Preface

What this book covers

What you need for this book

Who this book is for

Conventions

Reader feedback

Customer support

Errata

Piracy

Questions

1. Meeting Your Buddy – the Raspberry Pi

A glance at the Raspberry Pi board

Setting up for the first time

Installing the operating system

Purchasing your SD card

Downloading the required software

Windows

Mac OS X

Linux

Expanding the root filesystem

Logging in to the RasPi

Opening the desktop

Connecting the Raspberry Pi to the Internet

Internet connection through Wi-Fi dongle

Internet connection through Ethernet from a PC

Editing the command-line file of the RasPi

Turning on the RasPi

Changing cmdline.txt again to add the PC's Ethernet port IP address

Sharing the Internet connection between your PC and an Ethernet connection

Installing and opening the free SSH client on your PC

A crash course on Linux

The terminal and shell

Useful and frequently used Linux commands

Installing useful libraries

git-core

wiringPi

python-gpio

Be ready with Python and C

Writing and executing the Python program

Writing and executing the C program

Practice makes you perfect

Summary

2. Meeting the World of Electronics

Basic terminologies of electronics

Voltage

Current

Resistor

Capacitor

Open circuit and short circuit

Series and parallel connections

Pull-up and pull-down resistors

Communication protocols

UART

Serial Peripheral Interface

Inter-Integrated Circuit

Useful tips and precautions

Understanding the GPIO port

It's time to glow LEDs!

Shell script and GPIO

LED blink and Python

Let's blink the LED with C code

Summary

3. Measuring Distance Using Ultrasonic Sensors

The mysterious ultrasonic sensor

Distance calculation

Building the project!

Hardware setup

Software setup

Initial configuration

Setting the GPIO pins on the default mode

Sending and receiving the pulses

Calculation of distance

Fixing common problems

Is it showing the distance incorrectly?

Is the module not responding?

Are you measuring the distance less than 2 cm?

A wearable device for the visually impaired

Building the hardware

Software setup

Summary

4. Monitoring the Atmosphere Using Sensors

Sensor selection process

Criticality of an application

Selecting a sensor package

Sensor properties

Purchasing the sensor

Available sensors

InsideDHT – temperature and humidity sensors

Introducing the photoresistor (photocell)

Building the project

Hardware setup

Breadboard setup

Preparing the code

Code the DHT sensor and measure relative humidity and temperature

Code the LDR sensor and measure light variations

Putting all the parts together

Troubleshooting common problems

Received DHT data is not valid

The LDR sensor gives a zero value

Is the voltage correct?

Summary

5. Using an ADC to Interface any Analog Sensor with the Raspberry Pi

Analog-to-digital convertors

Data reception and signal conditioning

Amplification

Sampling and quantization

Types of ADC

Resolution of the ADC

The math behind ADC

Data output

MCP3008 for analog-to-digital conversion

Channels

Ground

SPI

Reference voltage

Supply voltage

Making your own sensor station

Generic software preparation

Using your sensor station – make a temperature logger

Know the LM36 temperature sensor

Write the application

Summary

6. Uploading Data Online – Spreadsheets, Mobile, and E-mails

Internet of Things

Sensor nodes

Communication

The cloud

Data analytics

Security concerns

Hardware setup

Synchronizing the clock with the Internet

Uploading data on Google spreadsheets

Live feed on mobile phones

Getting notified by e-mails

Integrating everything

Common problems faced

Summary

7. Creating an Image Sensor Using a Camera and OpenCV

Image processing

OpenCV

Camera interfacing with the RasPi

The RasPi camera modules

USB webcam

Live streaming using a network camera

Porting OpenCV

Testing

Create a motion detector

Preparing shell to compile OpenCV and wiringPi

Amazing projects for you

Summary

A. Shopping List

Basic requirements

Sensors

Integrated chips

Components

Others

Index

Raspberry Pi Sensors

Copyright © 2015 Packt Publishing

All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, without the prior written permission of the publisher, except in the case of brief quotations embedded in critical articles or reviews.

Every effort has been made in the preparation of this book to ensure the accuracy of the information presented. However, the information contained in this book is sold without warranty, either express or implied. Neither the author, nor Packt Publishing, and its dealers and distributors will be held liable for any damages caused or alleged to be caused directly or indirectly by this book.

Packt Publishing has endeavored to provide trademark information about all of the companies and products mentioned in this book by the appropriate use of capitals. However, Packt Publishing cannot guarantee the accuracy of this information.

First published: April 2015

Production reference: 1240415

Published by Packt Publishing Ltd.

Livery Place

35 Livery Street

Birmingham B3 2PB, UK.

ISBN 978-1-78439-361-8

www.packtpub.com

Cover image by Rushi Gajjar

Credits

Author

Rushi Gajjar

Reviewers

David Alcoba

Siddharth Bhave

Cédric Verstraeten

Commissioning Editor

Amarabha Banerjee

Acquisition Editor

Owen Roberts

Content Development Editor

Natasha Dsouza

Technical Editors

Tanmayee Patil

Shiny Poojary

Sebastian Rodrigues

Copy Editors

Karuna Narayanan

Vikrant Phadke

Project Coordinator

Rashi Khivansara

Proofreaders

Simran Bhogal

Safis Editing

Clyde Jenkins

Indexer

Rekha Nair

Graphics

Sheetal Aute

Disha Haria

Production Coordinator

Shantanu N. Zagade

Cover Work

Shantanu N. Zagade

About the Author

Rushi Gajjar is an embedded systems hardware developer and a lifetime electronics enthusiast. He works in the field of research and development of high-speed single-board embedded computers and wireless sensor nodes for the Internet of Things. Apart from that, he studied MTech in embedded systems by being involved in research at VIT University, Vellore.

Prior to this, his extensive work as a freelancer in the domain of electronics hardware design introduced him to rapid prototyping development boards such as the Raspberry Pi. In his spare time, he loves to develop projects on Raspberry Pi that include vision, data logging, web servers, and machine learning automation systems. He loves to teach Raspberry Pi projects to school students.

His vision encompasses connecting every entity in the world to the Internet to enhance the human living experience. His hobbies include playing the tabla, photography, and travelling.

Acknowledgements

First of all, I must say thanks to my acquisition edito...