I’m one of those people with boxes full of devices, waiting to be used in experiments… And from time to time, I dive into those boxes to fill in the gaps in between other tasks. So these are the results of my first Raspberry Pi Compute Module experiments!
These are all the links of my presentation at BeJUG in Waregem, Monday, July 24, 2024.
These are all the links of my presentation at the JChampions Conference, Monday January 29, 2024, 16:00 CET.
One of the most “fancy” electronic components is definitely a LED strip. It’s really cool to control a long strip of lights with only a few lines of code… But, there is a problem. The timing of the signals is crucial to reliably control these strips. Both Python and Java on a Raspberry Pi can struggle with these timings as they are running on Linux, a non-real-time operating system. So, for instance, pauses in the garbage collection of the Java virtual machine, or any glitch in the operating system can cause unexpected effects on the LED strips. That’s why in most projects, a microcontroller (Arduino, Raspberry Pi Pico, ESP32,…) is used to drive the LED strip. In my search for a good solution to use LED strips with Java, I stumbled on the Pixelblaze Output Expander. This small device is controlled through a serial interface, and handles the control of the LED strip. As it turns out, this is a perfect solution to offload the timing-critical operations from the Raspberry Pi and have reliable output on a LED strip.
These are all the links of my presentation at Devoxx Belgium, Wednesday 12:00-12:50, Room 7.
Yes, the Raspberry Pi Operating System is awesome! But the Pi4J project made it if even more awesome by adding “goodies” for Java developers! Pi4J OS is not yet another OS, but the official Raspberry Pi OS, with additional tools and preconfigurations to make it the ideal OS for any Java and JavaFX developer who wants to use a Raspberry Pi.
To make it as easy as possible to get started with Java on the Raspberry Pi to interact with electronic components, I started a new section on the Pi4J website with JBang examples.
Writing has always been my passion, and even in my previous jobs as a developer, I stood out as the one who enjoyed creating and maintaining documentation. But June 9th, 2023, marked my first birthday as a full-time technical writer at Azul. Yes, it’s already a year ago that I changed from being a developer-who-also-writes to a writer-who-also-develops. Let’s take a moment to reflect on my incredible journey over the past year.
After my talk at J-Fall I got the question what is required to get started with #JavaOnRaspberryPi. In my book I list the components that are used, but indeed a short overview was missing (it’s now added to the ebook…). So here we go:
Links used in my talks at Devoxx 2022 (Antwerp, Belgium) and J-Fall (Ede, The Netherlands).
As I’m becoming a senior developer in terms of age, I’ve transitioned from one language to another. One of my main interests has always been clean, easy-to-understand UIs (User Interface). That journey started for me with Director (to create multimedia CD-ROMs), Flash website animation, and Flex Rich Internet Applications (= “Flash on steroids”). When I started developing with Java over 10 years ago, we had some projects with the early versions of Vaadin and JavaFX. As I went on with serverside applications, I only continued with JavaFX for some personal and side projects, and loved the way you can create a UI both with XML (FXML actually) and code, exactly the same approach I loved with Flex. Since then, my love for Java and JavaFX only grew and it’s still my major programming environment.
As part of the Pi4J project, we created an example game with JavaFX and FXGL that uses an Arcade kit with a Joystick and big push buttons. The test setup for this project was kicking around my desk, so that was the perfect victim for my next 3D printing project…
A few years ago I did my first experiments with an MQTT server (Mosquitto) running on a Raspberry Pi to connect an Arduino and Raspberry Pi for the drumbooth of my son. The full process is described in my book “Getting Started with Java on the Raspberry Pi”.
Are you a serious Java-developer looking for a fun project? Or want to learn something completely new and use your Java-knowledge to control electronic components? Here we go with this small project to get you introduced to the world of electronics programming!
Today I could give my talk “Having fun with Java and JavaFX on the Raspberry Pi” at the JFXDays. Normally this event takes place in Zurich, but this year also went virtual because… well because of 2020…
Today I had my first Devoxx talk, after my Java virtual talk a few weeks ago at the “Oracle Groundbreakers APAC Virtual Tour 2020” conference (21/10)! The event in Ukraine also went virtual which gave me the opportunity to share my love for Java, JavaFX and the Raspberry Pi again.
Today I had the honor to speak at the “Oracle Groundbreakers APAC Virtual Tour 2020” conference. And of course the title of my talk was “Java and JavaFX on the Raspberry Pi”.
A topic which comes up from time to time in questions related to Java and the Raspberry Pi, is the support of the 4th version of this board in combination with Pi4J, “the friendly object-oriented I/O API and implementation library for Java programmers to access the full I/O capabilities of the Raspberry Pi “.
In my book “Getting Started with Java on Raspberry Pi” I dedicated a chapter on Pi4J, the leading framework to combine the power of Java with the hardware capabilities of the Raspberry Pi. This project which was started in 2012 by Robert Savage, evolved during the years to be able to support all the different Raspberry Pi-versions and many types of hardware components.
While looking for a cheap and nice component to demonstrate the use of SPI (Serial Peripheral Interface) I found out this 8x8 matrix LED display on a board with a MAX7219 chip is the perfect piece of hardware!
Pi4J contains helper methods to minimize the work needed to use certain hardware modules on the Pi with Java. As an example, we will be using “GpioLcdDisplay” to control an LCD with 2 rows of 16 characters. After requesting the weather forecast from a public website, we will visualize this on the LCD display.
Trisha Gee (Coder, blogger, speaker, Developer Advocate at JetBrains, @trisha_gee), which I interviewed for “Chapter 4: Choosing an IDE”, and Josh Long (Spring Developer Advocate at Pivotal, @starbuxman) worked together on a blog series in which they showed the power of reactive data produced by a Spring application. Instead of repeating a REST call each time you want to get data from the server, you do one call which returns a continuous stream in which new data is pushed based on an interval.
See https://www.pi4j.com/1.2/index.html
This project is intended to provide a friendly object-oriented I/O API and implementation libraries for Java Programmers to access the full I/O capabilities of the Raspberry Pi platform. This project abstracts the low-level native integration and interrupt monitoring to enable Java programmers to focus on implementing their application business logic.
As I was learning Spring Boot myself, I thought the easiest way to learn was trying to build an example and write about it. So here we go… :-)
While trying out what Pi4J can do, I found it could easily be extended with a JavaFX application to provide info about the headers on a Pi board. This could later be extended to a remote/local (touch) User Interface using the REST interface from this post.
As my daily work mainly is Java and back-end stuff on “real servers”, I set myself for 2019 as a personal goal to experiment with Java 11 on a Raspberry PI.
Based on the previous blog posts
So there is one “small” step remaining: build something which actually does something on the PI, talking to the GPIO’s and show what’s happening.
Spoiler alert: this is what’s is going to look like:
Is Java your first programming language and do you want to get up and running fast? Or maybe you are already an experienced programmer in another language and want to give Java a try?
For sale as ebook on Leanpub, with continuous free updates!
When I first managed to blink a LED connected to a Raspberry Pi with Java, I was super excited!