Raspberry Pi for Python Programmers Cookbook

Raspberry Pi for Python Programmers Cookbook - Second Edition

Overview of this book

Raspberry Pi cookbook for Python Programmers is a practical guide for getting the most out of this little computer. This book begins by guiding you through setting up the Raspberry Pi, performing tasks using Python 3 and introduces the first steps to interface with electronics. As you work through each chapter you will build up your skills and knowledge and apply them as you progress throughout the book, delving further and further into the unique abilities and features of the Raspberry Pi. Later, you will learn how to automate tasks by accessing files, build applications using the popular Tkinter library and create games by controlling graphics on screen. You will harness the power of the built-in graphics processor by using Pi3D to generate your own high quality 3D graphics and environments. Connect directly to the Raspberry Pi’s hardware pins to control electronics from switching on LEDs and responding to push buttons right through to driving motors and servos. Learn how to monitor sensors to gather real life data and to use it to control other devices, and view the results over the Internet. Apply what you have learnt by creating your own Pi-Rover or Pi-Hexipod robots. Finally, we will explore using many of the purpose built add-ons available for the Raspberry Pi, as well as interfacing with common household devices in new ways.

Raspberry Pi for Python Programmers Cookbook - Second Edition

Credits

About the Author

About the Reviewer

www.PacktPub.com

Preface

Free Chapter

Getting Started with a Raspberry Pi Computer

Introduction

Connecting the Raspberry Pi

Using NOOBS to set up your Raspberry Pi SD card

Networking and connecting your Raspberry Pi to the Internet via the LAN connector

Using built-in Wi-Fi and Bluetooth on the Raspberry Pi

Configuring your network manually

Networking directly to a laptop or computer

Networking and connecting your Raspberry Pi to the Internet via a USB Wi-Fi dongle

Connecting to the Internet through a proxy server

Connecting remotely to the Raspberry Pi over the network using VNC

Connecting remotely to the Raspberry Pi over the network using SSH (and X11 Forwarding)

Sharing the home folder of the Raspberry Pi with SMB

Keeping the Raspberry Pi up to date

Starting with Python Strings, Files, and Menus

Introduction

Working with text and strings

Using files and handling errors

Creating a boot-up menu

Creating a self-defining menu

Using Python for Automation and Productivity

Introduction

Using Tkinter to create graphical user interfaces

Creating a graphical application – Start menu

Displaying photo information in an application

Organizing your photos automatically

Creating Games and Graphics

Introduction

Using IDLE3 to debug your programs

Drawing lines using a mouse on Tkinter Canvas

Creating a bat and ball game

Creating an overhead scrolling game

Creating 3D Graphics

Introduction

Starting with 3D coordinates and vertices

Creating and importing 3D models

Creating a 3D world to roam in

Building 3D maps and mazes

Using Python to Drive Hardware

Introduction

Controlling an LED

Responding to a button

A controlled shutdown button

The GPIO keypad input

Multiplexed color LEDs

Writing messages using Persistence of Vision

Sense and Display Real-World Data

Introduction

Using devices with the IC bus

Reading analog data using an analog-to-digital converter

Logging and plotting data

Extending the Raspberry Pi GPIO with an I/O expander

Capturing data in an SQLite database

Viewing data from your own webserver

Sensing and sending data to online services

Creating Projects with the Raspberry Pi Camera Module

Introduction

Getting started with the Raspberry Pi camera module

Using the camera with Python

Generating a time-lapse video

Creating a stop frame animation

Making a QR code reader

Discover and experiment with OpenCV

Color detection with OpenCV

Performing motion tracking with OpenCV

Building Robots

Introduction

Building a Rover-Pi robot with forward driving motors

Using advanced motor control

Building a six-legged Pi-Bug robot

Controlling servos directly with Servoblaster

Using an Infra-Red Remote Control with your Raspberry Pi

Avoiding objects and obstacles

Getting a sense of direction

Interfacing with Technology

Introduction

Automating your home with remote sockets

Hardware and Software List

Index

Customer Reviews

5 star

4 star

3 star

2 star

1 star

Color detection with OpenCV

We shall begin experimenting with OpenCV by performing some basic operations on live image data. In this recipe, we shall perform some basic image processing to allow detection of different colored objects and track their location on screen.

Getting ready

In addition to the setup from the previous recipe, you will need a suitable colored object to track. For example, a small colored ball, a suitable colored mug, or a pencil with a square of colored paper taped to it is ideal. The example should allow you to detect the location (indicated by a color spot) of blue, green, red, magenta (pink) or yellow objects.

We can use OpenCV to detect colored objects in an image

How to do it…

Create the following opencv_display.py script:

#!/usr/bin/python3
#opencv_display.py
from picamera.array import PiRGBArray
from picamera import PiCamera
import time
import cv2

import opencv_color_detect as PROCESS  

def show_images(images,text,MODE):          
  # show the frame
  cv2.putText...

Raspberry Pi for Python Programmers Cookbook - Second Edition

Raspberry Pi for Python Programmers Cookbook - Second Edition

Overview of this book

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Current Title:

Raspberry Pi for Python Programmers Cookbook - Second Edition

Color detection with OpenCV

Getting ready

How to do it…