Check out the newest tutorial from Erin St Blaine: Get WLED running on your MatrixPortal board and control an LED matrix with no coding. This is a really cool project — we’ve been wanting to see WLED’s amazing 2d animation effects on a high resolution matrix display for ages. As an extra bonus, we’ve gotten it working with the MoonModules fork of WLED which also includes a whole array of new 2d animations from Animartrix. The kaleidoscope animations are blowing our minds!

This project was inspired by Living Stained Glass as seen at the Autumn Lights Festival in Oakland, CA.

From the guide:

Make a glowing stained glass window with over 2000 LEDs that animate and glow in hundreds of different patterns and colors, all without writing a line of code. The magic lies with WLED, a free, open-source LED animation program that runs over WiFi. Control your LED matrix with your smart phone or web browser, and watch your creation dance.

This guide uses the MoonModules v 14.5.0 beta (“Small Step”) fork of WLED, which works on the MatrixPortal S3. As a bonus, it also contains the Animartrix library of effects — a large pool of brand-new 2d animations that turn your LED matrix into a whirling kaleidoscope of color.

Use a laser cutter or a Cricut vinyl cutter to create a “resist” layer out of opaque material, and a black LED acrylic layer for diffusion, to make a beautiful stained glass window style art piece that shifts and moves with colored lights.

Full tutorial here: https://learn.adafruit.com/matrix-portal-stained-glass-with-wled/

Check out the latest tutorial from Erin St Blaine: build a sound reactive music visualizer light for your wall or living room that pulses and animates with your favorite color palettes when your music is playing. Place it on top of your home stereo speaker for a fantastic living room light show that you made yourself.

This guide will show you how to choose your favorite shape and set it up in LightBurn for laser cutting, with size and rotation variations so that the cutout appears to “move” when animated lights move across the edge of the acrylic layers. Connect your lights to the Mini Sparkle Motion controller and your shape will appear to grow and pulse to the beat.

This is one of the best looking sound-reactive projects we’ve seen to date, and it uses the free, open-source WLED software which is easy to install and use with no coding required. Tweak the audio settings to pulse beautifully in time with your favorite style of music.

From the guide:

Turn your living room into a mini light show with this audio reactive laser-cut Star Illusion. This layered acrylic sculpture comes alive with WLED and the Adafruit Mini Sparkle Motion board, easily creating sound-reactive animations that pulse, spin, and shimmer to your favorite music. The stacked layers, each slightly rotated and resized, create a hypnotic illusion of motion as NeoPixel LED light races along the edges. The result is a psychedelic, audio-responsive art piece that feels like it’s pulsing along with the beat.

This is a fairly easy project that requires a little bit of soldering but no coding at all. WLED can be installed with a few clicks, and animations and color palettes are controlled with your smart phone or web browser. It’s also easy to sync up multiple instances of WLED: Make a few with different shapes or put one on top of each of your speakers for a delightful music visualization experience.

Full tutorial: https://learn.adafruit.com/star-illusion-laser-cut-audio-reactive-light-with-wled/overview

If you read the above title, you might wonder how the switch to wayland (yes, the graphical stack replacing the venerable X11) can possibly relate to SSH agents. The answer is easy.

For as long as I can remember, as a long time user of gpg-agent as SSH agent (because my SSH key is a GPG sub-key) I relied on /etc/X11/Xsession.d/90gpg-agent that would configure the SSH_AUTH_SOCK environment variable (pointing to gpg-agent’s socket) provided that I added enable-ssh-support in ~/.gnupg/gpg-agent.conf.

Now when I switched to Wayland, that shell script used in the startup sequence of Xorg was no longer used. During a while I cheated a bit by setting SSH_AUTH_SOCK directly in my ~/.bashrc. But that only works for terminals, and not for other applications that are started by the session manager (which is basically systemd --user).

So how is that supposed to work out of the box nowadays? The SSH agents (as packaged in Debian) have all adopted the same trick, their .socket unit have an ExecStartPost setting which runs systemctl --user set-environment SSH_AUTH_SOCK=some-value. This command dynamically modifies the environment of the running systemd daemon and thus influences the environment for the future units started. Putting this in a socket unit ensures an early run, before most of the applications are started so it’s a good choice. They tend to also explicitly ensure this with a directive like Before=graphical-session-pre.target.

However, in a typical installation you end up with multiple SSH agents (right now I have ssh-agent, gpg-agent, and gcr-ssh-agent), which one is the one that the user ends up using? Well, that is not clearly defined, the one that wins is the one that runs last… because each of them overwrites the value in the systemd environment.

Some of them fight to have that place (cf #1079246 for gcr-ssh-agent) by setting explicit After directives. In the above bug I argue that we should let gpg-agent.socket have the priority since that’s the only one that is not enabled by default and that requires the user to opt-in. However, ultimately there will always be cases where you will want to be explicit about the SSH agent that should win.

You could rely on systemd overrides to add/remove ordering directives but that’s pretty fragile. Instead the right way to deal with this is to “mask” the socket units of the SSH agents that you don’t want. Note that disabling (i.e. systemctl --user disable) either will not work[1] or will not be sufficient[2]. In my case, I wanted to keep gpg-agent.socket so I masked gcr-ssh-agent.socket and ssh-agent.socket:

$ systemctl --user mask ssh-agent.socket gcr-ssh-agent.socket
Created symlink '/home/rhertzog/.config/systemd/user/ssh-agent.socket' → '/dev/null'.
Created symlink '/home/rhertzog/.config/systemd/user/gcr-ssh-agent.socket' → '/dev/null'.

Note that if you want that behaviour to apply to all users of your computer, you can use sudo systemctl --global mask ssh-agent.socket gcr-ssh-agent.socket. Now on next login, you will only get a single ssh agent socket unit that runs and the SSH_AUTH_SOCK value will thus be predictable again!

Hopefully you will find that useful as it’s already the second time that I stumble upon this either for me or for a relative. Next time, I will know where to look it up.

[1]: If you try to run systemctl --user disable gcr-ssh-agent.socket, you will get a message saying that it will not work because the unit is enabled for all users at the “global” level. You can do it with --global instead of --user but it doesn’t help, cf below.

[2]: Disabling an unit basically means stopping to explicitely schedule its startup as part of a desired target. However, the unit can still be started as a dependency of other units and that’s the case here because a socket unit will typically be pulled in by its corresponding service unit.