gnoMint is the name of the tool. I hope I will not forget that. gnoMint!

To remind myself, here is a list of the searches I tried without success:

  • ubuntu ca manager
  • ubuntu ca certificate sign manager
  • ubuntu ca certificate sign manager gui
  • ubuntu ca manager gui
  • gtk ca manager gui
  • gtk certificate authority manager gui
  • gtk ssl certificate manager gui
  • ubuntu ssl certificate manager gui
  • ubuntu certificate manager gui
  • ubuntu CA manager gui
  • CA manager gui

Vor einiger Zeit hab ich erklärt, wie man den Facebook Chat in Bitlbee benutzen kann. Seit Version 3.0.5 kann Bitlbee OAuth, so dass man sich darüber verbinden kann, ohne sein Passwort speichern zu müssen. Im Bitlbee Wiki steht, wie es geht:

acc add jabber username@chat.facebook.com
acc fb set oauth on
acc fb on

Danach startet in einem neuen Fenster die Authorisierung mit Facebook.

Benutzernamen statt -nummern anzeigen

Um die angezeigten numerischen IDs der Facebook Nutzer in deren Benutzernamen zu konvertieren, braucht Bitlbee die folgende Einstellung:

account fb set nick_source full_name

Neu verbinden, dann gehts.

Jeroen recently notified me, that my blog's feed at http://lekv.de/feed was broken and returned 403 - Forbidden. Looking into the directory Blogofile renders the site into, I found, that the feed is contained in a file named index.xml. However the VirtualHost configuration of my blog only contained index.html in its DirectoryIndex directive. Adding index.xml to the list solved the issue.

Thank you Jeroen for the hint!

This is a translation of my post on measuring temperature with linux, written in German.

The Idea

There are several possibilities to measure temperatures with your computer. 1-Wire sensors like the DS18S20 offer a simple and affordable solution, as it digitalizes the temperature directly inside the sensor and offers an easy interface to query the result. Hence there is no need for analog circuitry or calibration. A comprehensive article on how to wire the sensors to the computer's serial port can be found here. Then there also is the datasheet of the manufacturer as well.

Soldering up

A couple of weeks ago I soldered together a bunch of electronic parts and now I can use my computer to measure room and outside temperatures. For detailed schematics I referred to the aforementioned article.

Part List

  • Any amount of sesors DS18S20 (exactly this part!)
  • One diode 1N5817 per sensor (optional to reduce glitches)
  • Two 1N5818 Schottky diodes (also known as hot carrier diodes)
  • One 1N5234 6.3 Volt zener diode
  • One 1N5228 3.9 Volt zener diode
  • One 1.5 kΩ resistor

Multiple sensors can be hooked up in parallel and 3.5mm stereo jacks are a good option for that. When connecting a larger number of sensors the parasitical power supply will be insufficient and an active power source will be needed. For this purpose, the third pin of the stereo jacks will come handy.

To reduce glitches, you also can solder a 1N5817 diode directly onto the sensor between GND and DATA so that it is open from GND to DATA and blocked from DATA to GND.






Software

Soon I am going to post a tutorial on how to use Metricfire to plot the measured temperature values into nice graphs.

Digitemp

For starters you can use Digitemp to verify the sensors work correctly. First you have to create a configuration file by running

pimp@eekkater:~$ digitemp_DS9097 -i -s /dev/ttyS0
DigiTemp v3.5.0 Copyright 1996-2007 by Brian C. Lane
GNU Public License v2.0 - http://www.digitemp.com
Turning off all DS2409 Couplers
..
Searching the 1-Wire LAN
10AC010202080029 : DS1820/DS18S20/DS1920 Temperature Sensor
1032D4010208008F : DS1820/DS18S20/DS1920 Temperature Sensor
ROM #0 : 10AC010202080029
ROM #1 : 1032D4010208008F
Wrote .digitemprc

This will add all sensors to the configuration file for future calls. Afterwards you can query all sensors at once with digitemp_DS9097 -a.

pimp@eekkater:~$ digitemp_DS9097 -a
DigiTemp v3.5.0 Copyright 1996-2007 by Brian C. Lane
GNU Public License v2.0 - http://www.digitemp.com
Apr 10 00:43:59 Sensor 0 C: 11.94 F: 53.49
Apr 10 00:44:00 Sensor 1 C: 21.88 F: 71.38

Der Plan

Um mit einem PC Temperaturen zu messen gibt es mehrere Möglichkeiten. Eine relativ einfache sind 1-Wire Sensoren wie der DS18S20, die die Temperatur bereits im Sensor digitalisieren und die sich über eine einfache Schnittstelle ausgelesen lassen. Somit entfällt eine analoge Schaltung zur Auswertung und eine lästige Kalibrierung. Eine gute Anleitung, wie man diese Sensoren betreibt, gibt es zum Beispiel hier. Außerdem gibt es natürlich das Datenblatt des Herstellers.

Das Gelöt

Vor ein paar Wochen habe ich einen Sensor mit ein paar anderen Bauteilen zusammengelötet und jetzt kann mein PC damit die Raumtemperatur messen.

Teileliste

  • Eine beliebige Anzahl Temperatursensoren DS18S20 (genau dieser!)
  • Pro Sensor eine 1N5817 Diode (optional, um Glitches zu reduzieren)
  • Zwei 1N5818 Schottky-Dioden
  • Eine 6,3 Volt Zener-Diode 1N5234
  • Eine 3,9 Volz Zener-Diode 1N5228
  • Ein 1,5 kΩ Widerstand

Mehrere Sensoren kann man parallel anschließen und dafür eignen sich 3,5mm Klinkenstecker ganz gut, für die es passende Kabel und Verteiler zu kaufen gibt. Ab einer größeren Zahl von Sensoren kann eine zusätzliche Stromversorgung nötig werden, da die parasitäre Versorgung über die Serialschnittstelle nur für wenige Sensoren ausreicht. Dafür steht dann der dritte Leiter der 3,5mm Stereokabel verfügbar.

Um Glitches zu reduzieren, kann man direkt am Sensor eine 1N5817 Diode zwischen GND und DATA löten, so dass sie von GND nach DATA offen ist und von DATA nach GND sperrt.






Software

Demnächst gibt es eine Anleitung, wie man die Messwerte mit Metricfire möglichst einfach zu schönen Graphen stricken kann.

Digitemp

Fürs erste hilft Digitemp weiter um zu überprüfen, dass die Sensoren funktionieren. Zunächst muss eine Konfigurationsdatei erstellt werden:

pimp@eekkater:~$ digitemp_DS9097 -i -s /dev/ttyS0
DigiTemp v3.5.0 Copyright 1996-2007 by Brian C. Lane
GNU Public License v2.0 - http://www.digitemp.com
Turning off all DS2409 Couplers
..
Searching the 1-Wire LAN
10AC010202080029 : DS1820/DS18S20/DS1920 Temperature Sensor
1032D4010208008F : DS1820/DS18S20/DS1920 Temperature Sensor
ROM #0 : 10AC010202080029
ROM #1 : 1032D4010208008F
Wrote .digitemprc

Dabei werden alle gefundenen Sensoren in die Konfigurationsdatei eingetragen. Anschließend kann man mit dem Befehl digitemp_DS9097 -a alle Sensoren gleichzeitig auslesen.

pimp@eekkater:~$ digitemp_DS9097 -a
DigiTemp v3.5.0 Copyright 1996-2007 by Brian C. Lane
GNU Public License v2.0 - http://www.digitemp.com
Apr 10 00:43:59 Sensor 0 C: 11.94 F: 53.49
Apr 10 00:44:00 Sensor 1 C: 21.88 F: 71.38

This article by SethRobertson titled On undoing, fixing, or removing commits in git explains how to fix or rewrite almost anything in Git. It just helped my to remove a sensitive API key from a file throughout the whole history of my repository.

Ealier I already wrote about using the gnome-keyring-daemon to automatically unlock the SSH key when logging into XFCE. The method I described in the latter of my posts had the drawback of launching a complete GNOME session together with all its associated services.

The way the developers of the daemon intended it to work uses DBUS to inject the global variables pointing the various sockets to be used by SSH and GnuPG into the global session environment. However XFCE does not support this injection which currently is one of the magic things happening when launching the GNOME environment at login time.

More information on the current state of the issue can be found in Redhat's Bugzilla in bug 551508. The workaround depicted there is to place the following into your ~/.profile file (or any other file evaluated during session initialization):

# add gnome-keyring-daemon to env
export `gnome-keyring-daemon --start`

In XFCE you can change the screen DPI in the Font tab in the Appearance dialog, which will instantly take effect. If you want to script the change, e.g. when upon connection with a docking station, you can use the following command:

xfconf-query -c xsettings -p /Xft/DPI -s <NEW_DPI>

To display the current DPI, you can just omit the -s <NEW_DPI> part.

Die Kette am Spinning-Rad knackt.

Die Kette am Spinning-Rad knackt nochmal.

Die Kette am Spinning-Rad reißt.

Ich schraube den Kettenschutz ab.

In der Fahrradwerkstatt kaufe ich eine neue Kette.

Ich baue das Schwungrad aus, die Schrauben lösen sich nur schwer.

Eine der Schrauben dreht sich beim Wiedereinbau rund.

Beim Baumarkt will ich eine neue Schraube kaufen.

Scheinbar gibt es neben normalen Schrauben auch noch Karosserieschrauben.

Ich kaufe eine normale Schraube, einen Gewindeschneider plus Einsatz und Schneideöl.

Ich würge ein Gewinde in die Schwungradachse und schraube alles wieder zusammen.

Der halbe Tag ist rum.

To get free (no ads) SSH access to an unrooted Android device you can use DroidSSHd. First install the latest APK from here. Then open the DroidSSHd app on your device and enter a password in Preferences, Service and Authentication, Password. After this, hit Start and you should be able to connect to the IP and Port displayed.

Setting up keybased logins

At this point, only SSH will work. SFTP or SCP are not yet working and to copy your SSH key, we will have to live with SSH alone. Assuming your public key file is located at .ssh/id_rsa.pub, run on your desktop computer:

cat .ssh/id_rsa.pub | ssh -p <PORT> <IP> "cat - > /mnt/sdcard/.key"

The file will not be visible in the Android file manager, but you will be able to select it in the Public Key preference in DroidSSHd. After selecting the key, you should be able to login without a password.

SFTP - Mount the Device's Filesystem

In order to mount the device via Fuse/SSH you have to get SFTP working. The DroidSSHd app currently does not provide the required sftp-server binary. However you can download it here (local copy, MD5). Next, transfer the binary to the device by running (again on the desktop):

cat /<PATH-TO>/sftp-server | ssh -p <PORT> <IP> "cat - > /data/data/br.com.bott.droidsshd/files/bin/sftp-server"

You will most likely also have to make the file executable, so SSH to your Android device and run

android@android:/mnt/sdcard $ chmod 755 /data/data/br.com.bott.droidsshd/files/bin/sftp-server

Now you should be able to mount the device from your desktop like so:

$ sshfs -p <PORT> <IP>:/ <MOUNTPOINT>

In my case, this was:

sshfs -p 9922 tab.ea:/ fuse/ssh/

You should now be able to copy files from and this location as normal. Enjoy.

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