Tagged "JavaOnRaspberryPi"

In this post you’ll learn how you can run a Java application on a Raspberry Pi Zero 1 to turn it in a controllable HDMI camera. I use such cameras in my setup with an ATEM Mini Pro HDMI video switcher. This allows me to have four different inputs for a very affordable price to create videos, tutorials, virtual conference talks, etc. As I wanted to be able to easily change the zoom level of these Raspberry Pi cameras, I created a small Java application with an API.

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!

Last week I was working on a blog post about Azul Zulu with JavaFX support for ARM systems, like the Raspberry Pi. As you can see in this video, I found out my little test application with a lot of “bouncing balls” started losing performance on the Raspberry Pi with more than 1000 of those balls.

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.

On July 15th of 2023, I published a post here about my initial experiments with CRaC on the Raspberry Pi. At that time, I found out that both the Linux kernel in Raspberry Pi OS and the Zulu Build of OpenJDK still needed some changes to work on the Raspberry Pi. I created a ticket in the Linux kernel project, which was solved by Phil Elwell. Last week, a new version of the Raspberry Pi OS, based on Debian Bookworm, was released. And in september, version 21 of OpenJDK was released and the Zulu Build of it, includes CRaC. So let’s see if we can use CRaC without issues, if we bring all this togheter.

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.

With the April release of the Zulu Build of OpenJDK, Azul announced the integration of CRaC in its version 17 of Java for Linux. Coordinated Restore at Checkpoint (CRaC) is a feature introduced in OpenJDK to improve Java’s application startup and warmup times to milliseconds from seconds or even minutes, by allowing a running application to pause, snapshot its state, and restart later, even on a different machine.

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.

The OpenJDK sources are now fully available and developed on GitHub as a result of Project Skara. Thanks to a lot of work done by the community, the full Java development flow has been migrated to GitHub while keeping the repository history. This process has been described on the GitHub blog.

Java Quick Start

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!

Introduction

When I first managed to blink a LED connected to a Raspberry Pi with Java, I was super excited!