I'm Remy, a developer from The Netherlands with a focus on C++, C, C#, Linux and embedded systems.
I currently work for
To read more or get in touch, click here. This is my personal website, these articles do not reflect or are based on work, opinions or policies of any of my (previous) employers. Any resemblance to reality is pure coincidence.
YouLessQt, helps you align the YouLess to an analog electricity meter16-9-2023 09:00 | Remy van Elst
The YouLess is a device that can help you monitor energy usage. It works on so called smart meters using a P1 port, it can monitor solar panels but it also works with regular old analog meters. I have an old style analog meter but I like gadgets and monitoring / reducing my energy usage just as much as the next guy so I bought one. It has an optical sensor that you paste (with tape) on your meter and that detects a little black bar on the rotor disc and using a rpm factor on your meter it calculates the electricity used. I has some trouble with the device when I set it up, it turned out to be aligned wrongly. It sometimes missed the black bar, so the numbers were incorrect. I wrote a little application using Qt and QML to show the raw light sensor values in a line graph to help me align the YouLess correctly. This post tells you more about the application, which of course is open source.Read more...
A docker image for Qt 5.15 LTS for Android, including OpenSSL and the KDE patch collection13-9-2023 22:00 | Remy van Elst
Recently I got an email from Google regarding the API level of Leaf Node Monitoring, my open source monitoring app for Windows, Linux and Android. The Play Store version must be updated to target API level 33. For Windows and Linux I'm building the app automatically in a CI environment but the Android build was still a manual process. Until now, because after a bunch of messing around with Android NDK versions, OpenSSL library paths and Qt compile flags I can automatically build Leaf Node Monitoring in my CI.
I'm using Woodpecker CI and that requires every build step to be executed in a Docker image. There are a few Qt docker images floating around but they are all using the pre-built 5.15.2 version by extracting it from the Qt Online Installer. That version is quite old, 5.15.15 LTS was released a few days ago for Commercial License Holders on August 31, so after 1 year it will become available as open source.
My docker image builds Qt from source using the
5.15 KDE Qt Patch Collection branch for Android and it includes OpenSSL. This is as far as I know the most up to date docker image for Qt 5.15, currently at 5.15.10 LTS.
Drawing a Circle in Qt QML three different ways05-07-2023 23:59 | Remy van Elst
Qt has no
Circle built in to QML as a basic type, as for example the
Rectangle or the
Button control. This post shows you how to get a
Circle in QML, from the most basic method (a
Rectangle with a
radius of 180) to more advanced methods, using the
c++ control based on
QQuickPaintedItem. I wanted to experiment with the
Canvas QML control and the
QQuickPaintedItem C++ interface to get a better understanding of Qt and QML drawing interfaces, this post reflects that journey including showing your grouped QML properties exposed from C++.
Site update, self-hosted search via pagefind01-07-2023 21:32 | Remy van Elst
This is a static site, meaning that no server-side processing occurs. All HTML is generated out of a few folders full of markdown source and then uploaded to the cluster. Searching on this site was always provided by a text-box form that sent you to google with 'site:raymii.org' appended to it. Works fine, but it sends all data to Google. With my recent removal of all Google Ads on this site, as well as tracking via Google Analytics, sending searches via Google seems wrong.
I recently found the
pagefind program which I now use on here, it is a self hosted static site search engine of sorts.
The sad state of Alpha emulators (for OpenVMS)Published: 30-04-2018 | Last update: 30-06-2023 22:31 | Author: Remy van Elst
OpenVMS 7.3 was the last version for the VAX architecture. All later versions (like 8.4) are only available for the Alpha CPU architecture or Intel's Itanium platform. Since I don't want hardware running, which is suprisingly hard to get in The Netherlands, Alpha machines, I want to be able to run it in an emulator. simh is the best open source VAX emulator, but it does not support Alpha. My adventure with es40, the only open source Alpha emulator (development halted 10 years ago) ended prematurely since it crashes all the time. The only other available options are FreeAXP, Charon-AXP, vtAlpha and EmuVM AlphaVM. Only FreeAXP is available as a free (but not open source) download, Charon had a personal version but that is nowhere to be found nowdays, vtAlpha doesn't offer a trial or free version and EmuVM Alphaserver also stopped with their free version. In this article I'll go over my adventure with FreeAXP and EmuVM.Read more...
My 24 year old HP Jornada can do things your modern iPhone still can't do!15-06-2023 01:30 | Remy van Elst
I like to tinker with old hardware. The DEC PDP-8 is my favorite retro computer and Office 2003 is the best version ever released IMHO. One of my other favorite retro devices is the HP Jornada 720. A small
handheld PC (smaller than a netbook) running Windows CE or in my case, Linux. It has a decent keyboard, CFL backlit screen, 32 MB of RAM(!), a compact Flash card for storage and a stylus for the resistive touchscreen. Oh and I got a 10Mbit PCMCIA network card, but wireless cards are also still available. It might be old, released in 1999, but can do one thing your modern iPhone can't.
Bare Metal Vi, boot into Vi without an OS!22-04-2023 22:30 | Remy van Elst
This guide shows you how to run
Vi without an operating system, bare metal. This is a follow up on my article from 2014 where I made a custom linux distro that would Boot to Vim, VIM as PID 1. This time we go further, we boot into
Vi without an operating system. This is made possible by Cosmopolitan, a
libc that outputs a POSIX-approved polyglot format that runs natively on Linux + Mac + Windows + FreeBSD + OpenBSD + NetBSD + BIOS with the best possible performance and the tiniest footprint imaginable.
OpenVMS 9.2 for x86, Installing HAProxy and troubleshooting UNIX file paths19-04-2023 22:30 | Remy van Elst
This article shows you how to install HAProxy on OpenVMS 9.2 for x86. I've often used HAProxy in my career as a sysadmin and find it a very useful tool. HAProxy is an open source, fast, reliable load balancer for TCP and HTTP-based applications. This guide assumes you've set up your OpenVMS system via my guide and the second part of my guide, that will give you a fully licensed OpenVMS installation with networking and SSH access. Since I've used HAProxy so very often to set up high-available clusters and load balancers, I was surprised but happy to see it ported to OpenVMS. This guide shows the setup but also a few OpenVMS specific quirks, like file paths and troubleshooting error messages / logs.Read more...
OpenVMS 9.2 for x86, Getting Started part 3, the WebUI16-04-2023 22:30 | Remy van Elst
OpenVMS on x86 is now available for hobbyists! Almost a year after the official release. This is a part 3 of my getting started guide. Part 2 ended with a working network setup and SSH access. In part 3 we'll do something very exciting, installing the WebUI, a web based management interface for OpenVMS. I'll also share a few smaller tidbits, like how to use the interactive text editor via an
ssh session and how to use
Site update, cookie consent popup (for a static site)Published: 22-03-2023 | Last update: 16-04-2023 19:30 | Author: Remy van Elst
A small site update this time, just to let you know that I've added a cookie consent popup to this static site. If you reject all cookies, you should not see any advertisements and aren't tracked by Google Analytics. It's open source, cookieconsent by Orest Bida.Read more...
OpenVMS 9.2 for x86, Getting Started part 2, auto boot, licenses, PAKs, networking and SSH15-04-2023 22:30 | Remy van Elst
OpenVMS on x86 is now available for hobbyists! Almost a year after the official release. This is a part 2 of my getting started guide. Part 1 ended with an installed system, this part continues with automatic startup, activating the license files (PAKs) and setting up networking including SSH access.Read more...