QRDN

tailscale VPN: Access home services by DNS name

dragon — Mon, 30 Mar 2026 00:00:00 +0200

Same problem as https://aottr.dev/posts/2024/08/homelab-using-the-same-local-domain-to-access-my-services-via-tailscale-vpn/: I have setup a tailscale mesh VPN, and want to access services in my home network even without their hosts being part of the VPN (think IoT devices without resources or support for the tailscale daemon).

Subnet Routes

The tailscale …

weechat accent color

dragon — Mon, 30 Mar 2026 00:00:00 +0200

Weechat config using an "accent" color for important UI elements which can quickly be changed (e.g. to switch between light and dark terminal color scheme):

/color alias 22 accent
/set buflist.format.buffer_current "${color:,accent}${format_buffer}"
/set weechat.bar.status.color_bg accent
/set weechat.bar.title.color_bg accent
/set …

Thunderbird Lightning: mark all-day events in month/multi-week calendar view

dragon — Sat, 28 Mar 2026 00:00:00 +0100

Thunderbird Lightning calendar in month or multi-week view should mark the empty space of days which have an all day event differently.

Write into your ~/.thunderbird/<profilename>/chrome/userChrome.css (maybe need to create the chrome/ directory too):

.calendar-month-day-box-list:has(calendar-month-day-box-item[status=CONFIRMED][allday=true]) {
  background: repeating-linear-gradient(
    -45deg,
    rgba …

Wolf Wärmepumpe auslesen

dragon — Mon, 29 Sep 2025 00:00:00 +0200

Wie erfasse ich den Stromverbrauch (und weitere Metriken) meiner Wolf Wärmepumpe?

Eingebaut ist eine "CHA-07/400V" Monoblock-Wärmepumpe, und im Steuergerät ein "WolfLink Pro" zur Digitalisierung.

Wolflink verbinden mit Netzwerk

Gemäß Anleitung ohne Smartset App möglich:

Das Gerät spannt einen WLAN Acccess Point auf, mit dem verbinden und dann auf http …

Heizkurve optimieren

dragon — Thu, 20 Mar 2025 00:00:00 +0100

Zielsetzung Energieverbrauch minimieren, dafür Vorlauftemperatur minimieren

Wärmepumpe arbeitet umso effizienter, je geringer der Temperaturhub ist. Vorlauf > 55°C gilt als ineffizient
(Gas)Brennwertgerät: Erhöht Effizienz (ggü Heizwertgerät), indem Wasserdampf kondensiert wird, der bei Verbrennung entsteht (bei Gas mehr als bei Öl wegen mehr Wasserstoff-Atomen). Dies umso besser/mehr möglich, je …

Re-Using tasmota smart plugs in home assistant

dragon — Mon, 10 Mar 2025 00:00:00 +0100

I use a few smart power plugs which include an ESP microcontroller, a relais, and a power meter. These run tasmota and report to home assistant (compare e.g. https://blog.koehntopp.info/2020/05/20/gosund-and-tasmota/)

Now I don't want to buy new plugs for all devices which I …

Monitoring a freifunk node

dragon — Thu, 26 Sep 2024 00:00:00 +0200

I own/operate a freifunk router, running the Freifunk Darmstadt firmware which is based on gluon, which itself is based on OpenWRT.

I'd like to monitor the operation of my node (e.g. wifi client count on 2.4 and 5 GHz), but I want to avoid building my own …

The Nightmare Stacks map

dragon — Sat, 29 Jul 2023 00:00:00 +0200

I very much enjoyed "The Nightmare Stacks" by Charles Stross, my favourite book of the "Laundry Files" series (as released so far).

The plot being placed in a real place, I used the excellent umap website to draw the places & campaign movements named in the book as an openstreetmap overlay …

checkmk setup details (inside podman container)

dragon — Fri, 06 Jan 2023 00:00:00 +0100

Things about CheckMK not (easily) found in the documentation.

Every host is pinged, this service is named "Check_MK".

Run containerized version in podman with podman --cap-add net_raw for ping to work

Install Plugins in containerized Raw edition:

$ podman exec -it -u cmk  checkmk  /bin/bash
OMD[cmk]:~$ cd /tmp …

Reading BTLE advertisements on Linux

dragon — Tue, 27 Dec 2022 00:00:00 +0100

Project context: reading environmental sensor data from card10 into influxDB.

GATT / ESS

epicardium (C Firmware) exports sensor data over Bluetooth GATT ESS (environmental sensing service).

GATT requires pairing, connecting → only 1:1, encrypted

Reading possible with card10_iaq_notify.py from https://git.card10.badge.events.ccc.de/card10/firmware/-/merge_requests/508 …

Merge multiple PDF pages into one page

dragon — Thu, 15 Dec 2022 00:00:00 +0100

Example scan a Credit Card, resulting in a PDF with two pages, each containing the image of one side of the card.

Join the images, put them onto one page (and add some 10px distance between them):

pdfjam input.pdf --nup 1x2 --noautoscale=true --fitpaper=true --delta "10 10" --outfile …

plasmashell stuck at 100% CPU

dragon — Thu, 25 Aug 2022 00:00:00 +0200

My fedora 35 had its plasmashell process stuck at 100% CPU, after some switching between wayland and X11 sessions. When trying to change global keyboard shortcuts (e.g. Alt-F1 for the App-Menu Launcher), it would freeze completely for like 30 seconds, repeatedly. A new user wouldn't have that problem.

The …

Notizen vom Einbau eines 3rd-party Autoradio

dragon — Thu, 24 Sep 2020 00:00:00 +0200

physikalischer Einbaurahmen: 2DIN ist ein Standard, der eigentliche Schacht im Skoda ist aber größer & man braucht einen (Plattform-spezifischen?) Rahmen vorne, der auf die Befestigungsschrauben mappt
"Standard" ist der ISO-Stecker, VW+Skoda+... nutzen Quadlock
- ISO: Pins standard, nur einige nicht belegt, und häufig "Dauerplus" und Zündung vertauscht
- Quadlock: sieht aus wie …

nextcloud on fedora 27, using snap

dragon — Sun, 24 Jun 2018 00:00:00 +0200

$ snap install nextcloud
$ sudo snap get nextcloud ports
Key          Value
ports.http   80
ports.https  443
$ sudo snap set nextcloud ports.https=12345 ports.http=12344
$ sudo $(which nextcloud.occ) install <admin-user> <admin-pw>

htc HD2 Startup sequence // howto update Bootloader

dragon — Sun, 18 Feb 2018 00:00:00 +0100

Source: https://forum.xda-developers.com/showthread.php?t=1402975

Startup

sequence

HSPL "tri colored-screen"
Bootloader: MAGLDR, cLK
one of
- recovery: CWM, TWRP, ...
- OS (Android, Windows, ...)

Magic Buttons at Startup:

HSPL: keep Volume down and press End call/Power once
MAGLDR: keep End call/Power

Update Bootloader

(with broken Start call …

Eigener Router bei unitymedia

dragon — Sat, 24 Sep 2016 00:00:00 +0200

Seit 1.8.2016 ist die Endgerätefreiheit per Gesetz garantiert, d.h. Provider dürfen mir als Kunden nicht mehr Modem/Router vorschreiben. Um das zu überprüfen, verborgt die FSFE derzeit passende Router, und ich hab das mal gemacht. Hier das detaillierte log:

Zusammenfassung

Verbindung erfolgreich: Ja
Telefoniedaten verfügbar: Ja, nach …

How to save a whole mediawiki into a git repo

dragon — Mon, 19 Sep 2016 00:00:00 +0200

Recently I tried to archive the contents of our old MediaWiki instance to a git repository. Somebody else had already done that, using some scripts from MediaWiki, but these ignored the page histories, saving only the recent version for each page, and offered no possibility to also save uploaded files …

Qt "ModelTest" application

dragon — Wed, 14 Sep 2016 00:00:00 +0200

Several sources on the Internet propose the ModelTest application to check whether custom QAbstractItemModel subclasses behave correctly. The application is contained in the official sources (Qt5 and Qt4), and documented (in a sense) in the official wiki. What is not clear, however:

The mentioned .pri file is missing, one version …

Git hosting software

dragon — Mon, 16 Mar 2015 00:00:00 +0100

Software	Link	Comment
GitLab	https://about.gitlab.com/
Gogs	https://gogs.io/	Security issues, single maintainer
Gitea	https://gitea.io/	Gogs community fork
Gitorious	https://gitorious.org/	Bought by GitLab, will shut down
Phabricator	http://phabricator.org/	Used by Wikimedia

debugging ANTLR4 Lexer

dragon — Fri, 13 Feb 2015 00:00:00 +0100

grun MyLexer tokens -tokens < testfile

invokes the TestRig on the Lexer spilling out the tokens it recognized. Example stdout:

[@0,0:9='google.com',<4>,1:0]
[@1,10:10='\n',<2>,1:10]
[@2,11:11='\t',<1>,2:0]

Format of this output: A list of tokens, where …

grep -f

dragon — Sun, 02 Nov 2014 00:00:00 +0100

grep -f patterns.txt is horribly slow. Even for l in cat patterns.txt ; do grep $l ; done is magnitudes faster.

Linking against a specific library version:

dragon — Fri, 15 Aug 2014 00:00:00 +0200

Linking against a specific library version: http://stackoverflow.com/a/3393372

old:

ld -lgif

new:

ld -l:libgif.so.1337
ld /lib/libgif.so.1337

This came up when writing https://github.com/azrdev/vlc-anigif. At the time, Archlinux had only giflib4 in its repos, but I needed functions from …

TIL - htop graphs

dragon — Tue, 05 Aug 2014 00:00:00 +0200

Today I learned: htop can show value history of the meters in the top bar: Go to configure them, then select any which has a [mode] in square brackets behind it - F4 toggles that mode, including live preview of plain number view, ascii-graphed history, and "LED" which are big ascii-arted …

Geld ist Müll

dragon — Thu, 31 Jul 2014 00:00:00 +0200

Hat so eine Papierverbrennungs/-recyclingsanlage eigentlich nen Modul um weggeschmissenes Papiergeld rauszufiltern? So den Geburtstagsumschlag mit 200€ von Oma und so? Oder ist das einfach weg?

TIL - Ofen

dragon — Thu, 31 Jul 2014 00:00:00 +0200

Heute gelernt: Wenn der Ofen nicht an geht, die Herdplatten aber tun, einfach mal die integrierte Uhr stellen - so als kleiner Schubs in Richtung "Strom ist wieder an, und wir bauen nicht mehr. Darfst weitermachen."

Brick It!

dragon — Tue, 15 Jul 2014 00:00:00 +0200

How to destroy your linux system… in multiple acts:

Brick your shell:
```
$($EDITOR)
```
Brick your binary lookup:
```
sudo chmod -x /usr/bin
```

(Source https://chaos.social/@tippfehlr/116239736803587751

Lol, Unicode…

dragon — Tue, 15 Jul 2014 00:00:00 +0200

Some Unicode findings:

📳 U+1F4F3 : VIBRATION MODE
🚂 U+1F682 : STEAM LOCOMOTIVE
📢 U+1F4E2 : PUBLIC ADDRESS LOUDSPEAKER
🍝 U+1F35D : SPAGHETTI

Migrating a router from DD-WRT to OpenWRT

dragon — Wed, 01 May 2013 00:00:00 +0200

How to exchange the DD-WRT firmware on your router by OpenWRT.

my Router: TL-WR1043ND Version (DE)v1.0

Old firmware: DD-WRT r19519

New firmware: OpenWRT "Attitude Adjustment" 12.09 Beta 2, filename: openwrt-ar71xx-generic-tl-wr1043nd-v1-squashfs-factory.bin

First revert back to the original TP-Link firmware[1]. Use the Web flash interface and a …

quick'n'dirty PXE

dragon — Sun, 17 Feb 2013 00:00:00 +0100

… on Archlinux:

wget -O /var/ftpd/ipxe.pxe http://releng.archlinux.org/pxeboot/
pacman -S tftp-hpa
sudo in.tftpd -L

append to dnsmasq-config on your dhcp-server:

dhcp-boot=/var/ftpd/ipxe.pxe,,<ip-of-tftp-server>

E135 backlight

dragon — Mon, 04 Feb 2013 00:00:00 +0100

Disclaimer: this article is rather old, and does not reflect linux' current state of brightness on the Thinkpad E135

first, it was fixed on maximum. no tool could change it, /sys/class/backlight/acpi_video0/brightness could be written to and changed, but the backlight didn't. Tried the solutions in^{1 …}

KMix with multiple identically named master channels

dragon — Mon, 04 Feb 2013 00:00:00 +0100

On the Thinkpad Edge E135, ALSA recognizes 2 sound cards (0 and 1), of which #1 is the analog one I want to use and control - but not the default one. alsamixer can control it via selecting the entries in its F6 menu, but still it's not the default one …

32bit wine-prefixes

dragon — Sat, 01 Dec 2012 00:00:00 +0100

tl;dr: WINEARCH=win32 creates a 32bit prefix, to confirm check if $WINEPREFIX/drive_c/Program Files (x86) exists

A wine prefix is a directory containing a lot of the files wine needs to simulate a windows installation. The "standard" wine prefix ~/.wine is used whenever you don't specify a different …