Book Image

Raspberry Pi 3 Projects for Java Programmers

By : Rajdeep Chandra, John Sirach, Pradeeka Seneviratne
Book Image

Raspberry Pi 3 Projects for Java Programmers

By: Rajdeep Chandra, John Sirach, Pradeeka Seneviratne

Overview of this book

Raspberry Pi is a small, low cost and yet very powerful development platform. It is used to interact with attached electronics by the use of it's GPIO pins for multiple use cases, mainly Home Automation and Robotics. Our book is a project-based guide that will show you how to utilize the Raspberry Pi's GPIO with Java and how you can leverage this utilization with your knowledge of Java. You will start with installing and setting up the necessary hardware to create a seamless development platform. You will then straightaway start by building a project that will utilize light for presence detection. Next, you will program the application, capable of handling real time data using MQTT and utilize RPC to publish data to Further, you will build a wireless robot on top of the zuma chassis with the Raspberry Pi as the main controller. Lastly, you will end the book with advanced projects that will help you to create a multi-purpose IoT controller along with building a security camera that will perform image capture and recognize faces with the help of notifications. By the end of the book, you will be able to build your own real world usable projects not limited to Home Automation, IoT and/or Robotics utilizing logic, user and web interfaces.
Table of Contents (8 chapters)
Integrating a Real-Time IoT Dashboard

Automatic switch based on environment lighting

In this section, we will be combining the built hardware components to automate the switching of the relay based on the environment lighting, including printing states to the LCD. Let's close all the code tabs in the editor and leave only the Main class open. If not already done, comment the relayExample(); method and uncomment the lightDependentSwitching() method. This last method will instantiate the LdrHandler class and pass on a RelaySwitch object. If you already have been playing with the darkThreshold member value in the LdrHandler class, you can press the Run application button and the application should start switching automatically and update the LCD statuses. When we play a little bit with the environment lighting by putting our hand over the LDR, the relay should close, and when light is reaching the LDR again, the relay should open.

We now have this...