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        <channel>
                <title>Petter Reinholdtsen</title>
                <description></description>
                <link>https://people.skolelinux.org/pere/blog/</link>
                <atom:link href="https://people.skolelinux.org/pere/blog/index.rss" rel="self" type="application/rss+xml" />
        
        <item>
                <title>LinuxCNC MQTT publisher component</title>
                <link>https://people.skolelinux.org/pere/blog/LinuxCNC_MQTT_publisher_component.html</link>
                <guid isPermaLink="true">https://people.skolelinux.org/pere/blog/LinuxCNC_MQTT_publisher_component.html</guid>
                <pubDate>Sun, 8 Jan 2023 19:30:00 +0100</pubDate>
                <description>&lt;p&gt;I watched &lt;a href=&quot;https://yewtu.be/watch?v=jmKUV3aNLjk&quot;&gt;a 2015
video from Andreas Schiffler&lt;/a&gt; the other day, where he set up
&lt;a href=&quot;https://linuxcnc.org/&quot;&gt;LinuxCNC&lt;/a&gt; to send status
information to the MQTT broker IBM Bluemix.  As I also use MQTT for
graphing, it occured to me that a generic MQTT LinuxCNC component
would be useful and I set out to implement it.  Today I got the first
draft limping along and submitted as
&lt;a href=&quot;https://github.com/LinuxCNC/linuxcnc/pull/2253&quot;&gt;a patch to the
LinuxCNC project&lt;/a&gt;.&lt;/p&gt;

&lt;p&gt;The simple part was setting up the MQTT publishing code in Python.
I already have set up other parts submitting data to my Mosquito MQTT
broker, so I could reuse that code.  Writing a LinuxCNC component in
Python as new to me, but using existing examples in the code
repository and the extensive documentation, this was fairly straight
forward.  The hardest part was creating a automated test for the
component to ensure it was working.  Testing it in a simulated
LinuxCNC machine proved very useful, as I discovered features I needed
that I had not thought of yet, and adjusted the code quite a bit to
make it easier to test without a operational MQTT broker
available.&lt;/p&gt;

&lt;p&gt;The draft is ready and working, but I am unsure which LinuxCNC HAL
pins I should collect and publish by default (in other words, the
default set of information pieces published), and how to get the
machine name from the LinuxCNC INI file.  The latter is a minor
detail, but I expect it would be useful in a setup with several
machines available.  I am hoping for feedback from the experienced
LinuxCNC developers and users, to make the component even better
before it can go into the mainland LinuxCNC code base.&lt;/p&gt;

&lt;p&gt;Since I started on the MQTT component, I came across
&lt;a href=&quot;https://yewtu.be/watch?v=Bqa2grG0XtA&quot;&gt;another video from Kent
VanderVelden where he combine LinuxCNC with a set of screen glasses
controlled by a Raspberry Pi&lt;/a&gt;, and it occured to me that it would
be useful for such use cases if LinuxCNC also provided a REST API for
querying its status.  I hope to start on such component once the MQTT
component is working well.&lt;/p&gt;
 
&lt;p&gt;As usual, if you use Bitcoin and want to show your support of my
activities, please send Bitcoin donations to my address
&lt;b&gt;&lt;a href=&quot;bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&quot;&gt;15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&lt;/a&gt;&lt;/b&gt;.&lt;/p&gt;
</description>
        </item>
        
        <item>
                <title>ONVIF IP camera management tool finally in Debian</title>
                <link>https://people.skolelinux.org/pere/blog/ONVIF_IP_camera_management_tool_finally_in_Debian.html</link>
                <guid isPermaLink="true">https://people.skolelinux.org/pere/blog/ONVIF_IP_camera_management_tool_finally_in_Debian.html</guid>
                <pubDate>Sat, 24 Dec 2022 08:00:00 +0100</pubDate>
                <description>&lt;p&gt;Merry Christmas to you all.  Here is a small gift to all those with
IP cameras following the &lt;a href=&quot;https://www.onvif.org/&quot;&gt;ONVIF
specification&lt;/a&gt;.  There is finally a nice command line and GUI tool
in Debian to manage ONVIF IP cameras.  After working with upstream for
a few months and sponsoring the upload, I am very happy to report that
the &lt;a href=&quot;https://tracker.debian.org/libonvif&quot;&gt;libonvif package&lt;/a&gt;
entered Debian Sid last night.&lt;/p&gt;

&lt;p&gt;The package provide a C library to communicate with such cameras, a
command line tool to locate and update settings of (like password) the
cameras and a GUI tool to configure and control the units as well as
preview the video from the camera.  Libonvif is available on Both
Linux and Windows and the GUI tool uses the Qt library.  The main
competitors are non-free software, while libonvif is GNU GPL licensed.
I am very glad Debian users in the future can control their cameras
using a free software system provided by Debian.  But the ONVIF world
is full of slightly broken firmware, where the cameras pretend to
follow the ONVIF specification but fail to set some configuration
values or refuse to provide video to more than one recipient at the
time, and the onvif project is quite young and might take a while
before it completely work with your camera.  Upstream seem eager to
improve the library, so handling any broken camera might be just &lt;a
href=&quot;https://github.com/sr99622/libonvif/&quot;&gt;a bug report away&lt;/a&gt;.&lt;/p&gt;

&lt;p&gt;The package just cleared NEW, and need a new source only upload
before it can enter testing.  This will happen in the next few
days.&lt;/p&gt;

&lt;p&gt;As usual, if you use Bitcoin and want to show your support of my
activities, please send Bitcoin donations to my address
&lt;b&gt;&lt;a href=&quot;bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&quot;&gt;15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&lt;/a&gt;&lt;/b&gt;.&lt;/p&gt;
</description>
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        <item>
                <title>Managing and using ONVIF IP cameras with Linux</title>
                <link>https://people.skolelinux.org/pere/blog/Managing_and_using_ONVIF_IP_cameras_with_Linux.html</link>
                <guid isPermaLink="true">https://people.skolelinux.org/pere/blog/Managing_and_using_ONVIF_IP_cameras_with_Linux.html</guid>
                <pubDate>Wed, 19 Oct 2022 12:30:00 +0200</pubDate>
                <description>&lt;p&gt;Recently I have been looking at how to control and collect data
from a handful IP cameras using Linux.  I both wanted to change their
settings and to make their imagery available via a free software
service under my control.  Here is a summary of the tools I found.&lt;/p&gt;

&lt;p&gt;First I had to identify the cameras and their protocols.  As far as
I could tell, they were using some SOAP looking protocol and their
internal web server seem to only work with Microsoft Internet Explorer
with some proprietary binary plugin, which in these days of course is
a security disaster and also made it impossible for me to use the
camera web interface.  Luckily I discovered that the SOAP looking
protocol is actually following &lt;a href=&quot;https://www.onvif.org/&quot;&gt;the
ONVIF specification&lt;/a&gt;, which seem to be supported by a lot of IP
cameras these days.&lt;/p&gt;

&lt;p&gt;Once the protocol was identified, I was able to find what appear to
be the most popular way to configure ONVIF cameras, the free software
Windows tool named
&lt;a href=&quot;https://sourceforge.net/projects/onvifdm/&quot;&gt;ONVIF Device
Manager&lt;/a&gt;.  Lacking any other options at the time, I tried
unsuccessfully to get it running using Wine, but was missing a dotnet
40 library and I found no way around it to run it on Linux.&lt;/p&gt;

&lt;p&gt;The next tool I found to configure the cameras were a non-free Linux Qt
client &lt;a href=&quot;https://www.lingodigit.com/onvif_nvcdemo.html&quot;&gt;ONVIF
Device Tool&lt;/a&gt;.  I did not like its terms of use, so did not spend
much time on it.&lt;/p&gt;

&lt;p&gt;To collect the video and make it available in a web interface, I
found the Zoneminder tool in Debian.  A recent version was able to
automatically detect and configure ONVIF devices, so I could use it to
set up motion detection in and collection of the camera output.  I had
initial problems getting the ONVIF autodetection to work, as both
Firefox and Chromium &lt;a href=&quot;https://bugs.debian.org/1001188&quot;&gt;refused
the inter-tab communication&lt;/a&gt; being used by the Zoneminder web
pages, but managed to get konqueror to work.  Apparently the &quot;Enhanced
Tracking Protection&quot; in Firefox cause the problem.  I ended up
upgrading to the Bookworm edition of Zoneminder in the process to try
to fix the issue, and believe the problem might be solved now.&lt;/p&gt;

&lt;p&gt;In the process I came across the nice Linux GUI tool
&lt;a href=&quot;https://gitlab.com/caspermeijn/onvifviewer/&quot;&gt;ONVIF Viewer&lt;/a&gt;
allowing me to preview the camera output and validate the login
passwords required.  Sadly its author has grown tired of maintaining
the software, so it might not see any future updates.  Which is sad,
as the viewer is sightly unstable and the picture tend to lock up.
Note, this lockup might be due to limitations in the cameras and not
the viewer implementation.  I suspect the camera is only able to
provide pictures to one client at the time, and the Zoneminder feed
might interfere with the GUI viewer.  I have
&lt;a href=&quot;https://bugs.debian.org/1000820&quot;&gt;asked for the tool to be
included in Debian&lt;/a&gt;.&lt;/p&gt;

&lt;p&gt;Finally, I found what appear to be very nice Linux free software
replacement for the Windows tool, named
&lt;a href=&quot;https://github.com/sr99622/libonvif/&quot;&gt;libonvif&lt;/a&gt;.  It
provide a C library to talk to ONVIF devices as well as a command line
and GUI tool using the library.  Using the GUI tool I was able to change
the admin passwords and update other settings of the cameras.  I have
&lt;a href=&quot;https://bugs.debian.org/1021980&quot;&gt;asked for the package to be
included in Debian&lt;/a&gt;.&lt;/p&gt;

&lt;p&gt;As usual, if you use Bitcoin and want to show your support of my
activities, please send Bitcoin donations to my address
&lt;b&gt;&lt;a href=&quot;bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&quot;&gt;15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&lt;/a&gt;&lt;/b&gt;.&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;Update 2022-10-20&lt;/strong&gt;: Since my initial publication of
this text, I got several suggestions for more free software Linux
tools.  There is &lt;a href=&quot;https://github.com/quatanium/python-onvif&quot;&gt;a
ONVIF python library&lt;/a&gt; (already
&lt;a href=&quot;https://bugs.debian.org/824240&quot;&gt;requested into Debian&lt;/a&gt;) and
&lt;a href=&quot;https://github.com/FalkTannhaeuser/python-onvif-zeep&quot;&gt;a python 3
fork&lt;/a&gt; using a different SOAP dependency.  There is also
&lt;a href=&quot;https://www.home-assistant.io/integrations/onvif/&quot;&gt;support for
ONVIF in Home Assistant&lt;/a&gt;, and there is an alternative to Zoneminder
called &lt;a href=&quot;https://www.shinobi.video/&quot;&gt;Shinobi&lt;/a&gt;.  The latter
two are not included in Debian either.  I have not tested any of these
so far.&lt;/p&gt;
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        <item>
                <title>Time to translate the Bullseye edition of the Debian Administrator&#39;s Handbook</title>
                <link>https://people.skolelinux.org/pere/blog/Time_to_translate_the_Bullseye_edition_of_the_Debian_Administrator_s_Handbook.html</link>
                <guid isPermaLink="true">https://people.skolelinux.org/pere/blog/Time_to_translate_the_Bullseye_edition_of_the_Debian_Administrator_s_Handbook.html</guid>
                <pubDate>Mon, 12 Sep 2022 15:45:00 +0200</pubDate>
                <description>&lt;p align=&quot;center&quot;&gt;&lt;img align=&quot;center&quot; src=&quot;http://people.skolelinux.org/pere/blog/images/2020-10-20-debian-handbook-nb-testprint.jpeg&quot; width=&quot;60%&quot;/&gt;&lt;/p&gt;

&lt;p&gt;(The picture is of the previous edition.)&lt;/p&gt;

&lt;p&gt;Almost two years after the previous Norwegian Bokmål translation of
the &quot;&lt;a href=&quot;https://debian-handbook.info/&quot;&gt;The Debian Administrator&#39;s
Handbook&lt;/a&gt;&quot; was published, a new edition is finally being prepared.  The
english text is updated, and it is time to start working on the
translations.  Around 37 percent of the strings have been updated, one
way or another, and the translations starting from a complete Debian Buster
edition now need to bring their translation up from 63% to 100%.  The
complete book is licensed using a Creative Commons license, and has
been published in several languages over the years.  The translations
are done by volunteers to bring Linux in their native tongue.  The
last time I checked, it complete text was available in English,
Norwegian Bokmål, German, Indonesian, Brazil Portuguese and Spanish.
In addition, work has been started for Arabic (Morocco), Catalan,
Chinese (Simplified), Chinese (Traditional), Croatian, Czech, Danish,
Dutch, French, Greek, Italian, Japanese, Korean, Persian, Polish,
Romanian, Russian, Swedish, Turkish and Vietnamese.&lt;/p&gt;

&lt;p&gt;The translation is conducted on
&lt;a href=&quot;https://hosted.weblate.org/projects/debian-handbook/&quot;&gt;the
hosted weblate project page&lt;/a&gt;.  Prospective translators are
recommeded to subscribe to
&lt;a href=&quot;http://lists.alioth.debian.org/mailman/listinfo/debian-handbook-translators&quot;&gt;the
translators mailing list&lt;/a&gt; and should also check out
&lt;a href=&quot;https://debian-handbook.info/contribute/&quot;&gt;the instructions for
contributors&lt;/a&gt;.&lt;/p&gt;

&lt;p&gt;I am one of the Norwegian Bokmål translators of this book, and we
have just started.  Your contribution is most welcome.&lt;/p&gt;

&lt;p&gt;As usual, if you use Bitcoin and want to show your support of my
activities, please send Bitcoin donations to my address
&lt;b&gt;&lt;a href=&quot;bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&quot;&gt;15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&lt;/a&gt;&lt;/b&gt;.&lt;/p&gt;
</description>
        </item>
        
        <item>
                <title>Automatic LinuxCNC servo PID tuning?</title>
                <link>https://people.skolelinux.org/pere/blog/Automatic_LinuxCNC_servo_PID_tuning_.html</link>
                <guid isPermaLink="true">https://people.skolelinux.org/pere/blog/Automatic_LinuxCNC_servo_PID_tuning_.html</guid>
                <pubDate>Sat, 16 Jul 2022 22:30:00 +0200</pubDate>
                <description>&lt;p&gt;While working on a CNC with servo motors controlled by the
&lt;a href=&quot;https://en.wikipedia.org/wiki/LinuxCNC&quot;&gt;LinuxCNC&lt;/a&gt;
&lt;a href=&quot;https://en.wikipedia.org/wiki/PID_controller&quot;&gt;PID
controller&lt;/a&gt;, I recently had to learn how to tune the collection of values
that control such mathematical machinery that a PID controller is.  It
proved to be a lot harder than I hoped, and I still have not succeeded
in getting the Z PID controller to successfully defy gravity, nor X
and Y to move accurately and reliably.  But while climbing up this
rather steep learning curve, I discovered that some motor control
systems are able to tune their PID controllers.  I got the impression
from the documentation that LinuxCNC were not.  This proved to be not
true.&lt;/p&gt;

&lt;p&gt;The LinuxCNC
&lt;a href=&quot;http://linuxcnc.org/docs/html/man/man9/pid.9.html&quot;&gt;pid
component&lt;/a&gt; is the recommended PID controller to use.  It uses eight
constants &lt;tt&gt;Pgain&lt;/tt&gt;, &lt;tt&gt;Igain&lt;/tt&gt;, &lt;tt&gt;Dgain&lt;/tt&gt;,
&lt;tt&gt;bias&lt;/tt&gt;, &lt;tt&gt;FF0&lt;/tt&gt;, &lt;tt&gt;FF1&lt;/tt&gt;, &lt;tt&gt;FF2&lt;/tt&gt; and
&lt;tt&gt;FF3&lt;/tt&gt; to calculate the output value based on current and wanted
state, and all of these need to have a sensible value for the
controller to behave properly.  Note, there are even more values
involved, theser are just the most important ones.  In my case I need
the X, Y and Z axes to follow the requested path with little error.
This has proved quite a challenge for someone who have never tuned a
PID controller before, but there is at least some help to be found.

&lt;p&gt;I discovered that included in LinuxCNC was this old PID component
at_pid claiming to have auto tuning capabilities.  Sadly it had been
neglected since 2011, and could not be used as a plug in replacement
for the default pid component.  One would have to rewriting the
LinuxCNC HAL setup to test at_pid.  This was rather sad, when I wanted
to quickly test auto tuning to see if it did a better job than me at
figuring out good P, I and D values to use.&lt;/p&gt;

&lt;p&gt;I decided to have a look if the situation could be improved.  This
involved trying to understand the code and history of the pid and
at_pid components.  Apparently they had a common ancestor, as code
structure, comments and variable names were quite close to each other.
Sadly this was not reflected in the git history, making it hard to
figure out what really happened.  My guess is that the author of
&lt;a href=&quot;https://github.com/LinuxCNC/linuxcnc/blob/master/src/hal/components/at_pid.c&quot;&gt;at_pid.c&lt;/a&gt;
took a version of
&lt;a href=&quot;https://github.com/LinuxCNC/linuxcnc/blob/master/src/hal/components/pid.c&quot;&gt;pid.c&lt;/a&gt;,
rewrote it to follow the structure he wished pid.c to have, then added
support for auto tuning and finally got it included into the LinuxCNC
repository.  The restructuring and lack of early history made it
harder to figure out which part of the code were relevant to the auto
tuning, and which part of the code needed to be updated to work the
same way as the current pid.c implementation.  I started by trying to
isolate relevant changes in pid.c, and applying them to at_pid.c.  My
aim was to make sure the at_pid component could replace the pid
component with a simple change in the HAL setup loadrt line, without
having to &quot;rewire&quot; the rest of the HAL configuration.  After a few
hours following this approach, I had learned quite a lot about the
code structure of both components, while concluding I was heading down
the wrong rabbit hole, and should get back to the surface and find a
different path.&lt;/p&gt;

&lt;p&gt;For the second attempt, I decided to throw away all the PID control
related part of the original at_pid.c, and instead isolate and lift
the auto tuning part of the code and inject it into a copy of pid.c.
This ensured compatibility with the current pid component, while
adding auto tuning as a run time option.  To make it easier to identify
the relevant parts in the future, I wrapped all the auto tuning code
with &#39;#ifdef AUTO_TUNER&#39;.  The end result behave just like the current
pid component by default, as that part of the code is identical.  The
&lt;a href=&quot;https://github.com/LinuxCNC/linuxcnc/pull/1820&quot;&gt;end result
entered the LinuxCNC master branch&lt;/a&gt; a few days ago.&lt;/p&gt;

&lt;p&gt;To enable auto tuning, one need to set a few HAL pins in the PID
component.  The most important ones are &lt;tt&gt;tune-effort&lt;/tt&gt;,
&lt;tt&gt;tune-mode&lt;/tt&gt; and &lt;tt&gt;tune-start&lt;/tt&gt;.  But lets take a step
back, and see what the auto tuning code will do.  I do not know the
mathematical foundation of the at_pid algorithm, but from observation
I can tell that the algorithm will, when enabled, produce a square
wave pattern centered around the &lt;tt&gt;bias&lt;/tt&gt; value on the output pin
of the PID controller.  This can be seen using the HAL Scope provided
by LinuxCNC.  In my case, this is translated into voltage (+-10V) sent
to the motor controller, which in turn is translated into motor speed.
So at_pid will ask the motor to move the axis back and forth.  The
number of cycles in the pattern is controlled by the
&lt;tt&gt;tune-cycles&lt;/tt&gt; pin, and the extremes of the wave pattern is
controlled by the &lt;tt&gt;tune-effort&lt;/tt&gt; pin.  Of course, trying to
change the direction of a physical object instantly (as in going
directly from a positive voltage to the equivalent negative voltage)
do not change velocity instantly, and it take some time for the object
to slow down and move in the opposite direction.  This result in a
more smooth movement wave form, as the axis in question were vibrating
back and forth.  When the axis reached the target speed in the
opposing direction, the auto tuner change direction again.  After
several of these changes, the average time delay between the &#39;peaks&#39;
and &#39;valleys&#39; of this movement graph is then used to calculate
proposed values for Pgain, Igain and Dgain, and insert them into the
HAL model to use by the pid controller.  The auto tuned settings are
not great, but htye work a lot better than the values I had been able
to cook up on my own, at least for the horizontal X and Y axis.  But I
had to use very small &lt;tt&gt;tune-effort&lt;tt&gt; values, as my motor
controllers error out if the voltage change too quickly.  I&#39;ve been
less lucky with the Z axis, which is moving a heavy object up and
down, and seem to confuse the algorithm.  The Z axis movement became a
lot better when I introduced a &lt;tt&gt;bias&lt;/tt&gt; value to counter the
gravitational drag, but I will have to work a lot more on the Z axis
PID values.&lt;/p&gt;

&lt;p&gt;Armed with this knowledge, it is time to look at how to do the
tuning.  Lets say the HAL configuration in question load the PID
component for X, Y and Z like this:&lt;/p&gt;
 
&lt;blockquote&gt;&lt;pre&gt;
loadrt pid names=pid.x,pid.y,pid.z
&lt;/pre&gt;&lt;/blockquote&gt;

&lt;p&gt;Armed with the new and improved at_pid component, the new line will
look like this:&lt;/p&gt;

&lt;blockquote&gt;&lt;pre&gt;
loadrt at_pid names=pid.x,pid.y,pid.z
&lt;/pre&gt;&lt;/blockquote&gt;

&lt;p&gt;The rest of the HAL setup can stay the same.  This work because the
components are referenced by name.  If the component had used count=3
instead, all use of pid.# had to be changed to at_pid.#.&lt;/p&gt;

&lt;p&gt;To start tuning the X axis, move the axis to the middle of its
range, to make sure it do not hit anything when it start moving back
and forth.  Next, set the &lt;tt&gt;tune-effort&lt;/tt&gt; to a low number in the
output range.  I used 0.1 as my initial value.  Next, assign 1 to the
&lt;tt&gt;tune-mode&lt;/tt&gt; value. Note, this will disable the pid controlling
part and feed 0 to the output pin, which in my case initially caused a
lot of drift.  In my case it proved to be a good idea with X and Y to
tune the motor driver to make sure 0 voltage stopped the motor
rotation.  On the other hand, for the Z axis this proved to be a bad
idea, so it will depend on your setup.  It might help to set the
&lt;tt&gt;bias&lt;/tt&gt; value to a output value that reduce or eliminate the
axis drift.  Finally, after setting &lt;tt&gt;tune-mode&lt;/tt&gt;, set
&lt;tt&gt;tune-start&lt;/tt&gt; to 1 to activate the auto tuning.  If all go well,
your axis will vibrate for a few seconds and when it is done, new
values for Pgain, Igain and Dgain will be active.  To test them,
change &lt;tt&gt;tune-mode&lt;/tt&gt; back to 0.  Note that this might cause the
machine to suddenly jerk as it bring the axis back to its commanded
position, which it might have drifted away from during tuning.  To
summarize with some halcmd lines:&lt;/p&gt;

&lt;blockquote&gt;&lt;pre&gt;
setp pid.x.tune-effort 0.1
setp pid.x.tune-mode 1
setp pid.x.tune-start 1
# wait for the tuning to complete
setp pid.x.tune-mode 0
&lt;/pre&gt;&lt;/blockquote&gt;

&lt;p&gt;After doing this task quite a few times while trying to figure out
how to properly tune the PID controllers on the machine in, I decided
to figure out if this process could be automated, and wrote a script
to do the entire tuning process from power on.  The end result will
ensure the machine is powered on and ready to run, home all axis if it
is not already done, check that the extra tuning pins are available,
move the axis to its mid point, run the auto tuning and re-enable the
pid controller when it is done.  It can be run several times.  Check
out the
&lt;a href=&quot;https://github.com/SebKuzminsky/MazakVQC1540/blob/bon-dev/scripts/run-auto-pid-tuner&quot;&gt;run-auto-pid-tuner&lt;/a&gt;
script on github if you want to learn how it is done.&lt;/p&gt;

&lt;p&gt;My hope is that this little adventure can inspire someone who know
more about motor PID controller tuning can implement even better
algorithms for automatic PID tuning in LinuxCNC, making life easier
for both me and all the others that want to use LinuxCNC but lack the
in depth knowledge needed to tune PID controllers well.&lt;/p&gt;

&lt;p&gt;As usual, if you use Bitcoin and want to show your support of my
activities, please send Bitcoin donations to my address
&lt;b&gt;&lt;a href=&quot;bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&quot;&gt;15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&lt;/a&gt;&lt;/b&gt;.&lt;/p&gt;
</description>
        </item>
        
        <item>
                <title>My free software activity of late (2022)</title>
                <link>https://people.skolelinux.org/pere/blog/My_free_software_activity_of_late__2022_.html</link>
                <guid isPermaLink="true">https://people.skolelinux.org/pere/blog/My_free_software_activity_of_late__2022_.html</guid>
                <pubDate>Mon, 20 Jun 2022 14:30:00 +0200</pubDate>
                <description>&lt;p&gt;I guess it is time to bring some light on the various free software
and open culture activities and projects I have worked on or been
involved in the last year and a half.&lt;/p&gt;

&lt;p&gt;First, lets mention the book
&lt;a href=&quot;http://www.hungry.com/~pere/publisher/&quot;&gt;releases I managed to
publish&lt;/a&gt;.  The Cory Doctorow book &quot;Hvordan knuse
overvåkningskapitalismen&quot; argue that it is not the magic machine
learning of the big technology companies that causes the surveillance
capitalism to thrive, it is the lack of trust busting to enforce
existing anti-monopoly laws.  I also published a family of
dictionaries for machinists, one sorted on the English words, one
sorted on the Norwegian and the last sorted on the North Sámi words.
A bit on the back burner but not forgotten is the Debian
Administrators Handbook, where a new edition is being worked on.  I
have not spent as much time as I want to help bring it to completion,
but hope I will get more spare time to look at it before the end of
the year.&lt;/p&gt;

&lt;p&gt;With my Debian had I have spent time on several projects, both
updating existing packages, helping to bring in new packages and
working with upstream projects to try to get them ready to go into
Debian.  The list is rather long, and I will only mention my own
isenkram, openmotor, vlc bittorrent plugin, xprintidle, norwegian
letter style for latex, bs1770gain, and recordmydesktop.  In addition
to these I have sponsored several packages into Debian, like audmes.&lt;/p&gt;

&lt;p&gt;The last year I have looked at several infrastructure projects for
collecting meter data and video surveillance recordings.  This include
several ONVIF related tools like onvifviewer and zoneminder as well as
rtl-433, wmbusmeters and rtl-wmbus.&lt;/p&gt;

&lt;p&gt;In parallel with this I have looked at fabrication related free
software solutions like pycam and LinuxCNC.  The latter recently
gained improved translation support using po4a and weblate, which was
a harder nut to crack that I had anticipated when I started.&lt;/p&gt;

&lt;p&gt;Several hours have been spent translating free software to
Norwegian Bokmål on the Weblate hosted service.  Do not have a
complete list, but you will find my contributions in at least gnucash,
minetest and po4a.&lt;/p&gt;

&lt;p&gt;I also spent quite some time on the Norwegian archiving specification
Noark 5, and its companion project Nikita implementing the API
specification for Noark 5.&lt;/p&gt;

&lt;p&gt;Recently I have been looking into free software tools to do company
accounting here in Norway., which present an interesting mix between
law, rules, regulations, format specifications and API interfaces.&lt;/p&gt;

&lt;p&gt;I guess I should also mention the Norwegian community driven
government interfacing projects Mimes Brønn and Fiksgatami, which have
ended up in a kind of limbo while the future of the projects is being
worked out.&lt;/p&gt;

&lt;p&gt;These are just a few of the projects I have been involved it, and
would like to give more visibility.  I&#39;ll stop here to avoid delaying
this post.&lt;/p&gt;

&lt;p&gt;As usual, if you use Bitcoin and want to show your support of my
activities, please send Bitcoin donations to my address
&lt;b&gt;&lt;a href=&quot;bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&quot;&gt;15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&lt;/a&gt;&lt;/b&gt;.&lt;/p&gt;
</description>
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        <item>
                <title>LinuxCNC translators life just got a bit easier</title>
                <link>https://people.skolelinux.org/pere/blog/LinuxCNC_translators_life_just_got_a_bit_easier.html</link>
                <guid isPermaLink="true">https://people.skolelinux.org/pere/blog/LinuxCNC_translators_life_just_got_a_bit_easier.html</guid>
                <pubDate>Fri, 3 Jun 2022 21:10:00 +0200</pubDate>
                <description>&lt;p&gt;Back in oktober last year, when I started looking at the
&lt;a href=&quot;https://en.wikipedia.org/wiki/LinuxCNC&quot;&gt;LinuxCNC&lt;/a&gt; system, I
proposed to change the documentation build system make life easier for
translators.  The original system consisted of independently written
documentation files for each language, with no automated way to track
changes done in other translations and no help for the translators to
know how much was left to translated.  By using
&lt;a href=&quot;https://po4a.org/&quot;&gt;the po4a system&lt;/a&gt; to generate POT and PO
files from the English documentation, this can be improved.  A small
team of LinuxCNC contributors got together and today our labour
finally payed off.  Since a few hours ago, it is now possible to
translate &lt;a href=&quot;https://hosted.weblate.org/projects/linuxcnc/&quot;&gt;the
LinuxCNC documentation on Weblate&lt;/a&gt;, alongside the program itself.&lt;/p&gt;

&lt;p&gt;The effort to migrate the documentation to use po4a has been both
slow and frustrating.  I am very happy we finally made it.&lt;/p&gt;

&lt;p&gt;As usual, if you use Bitcoin and want to show your support of my
activities, please send Bitcoin donations to my address
&lt;b&gt;&lt;a href=&quot;bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&quot;&gt;15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&lt;/a&gt;&lt;/b&gt;.&lt;/p&gt;
</description>
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        <item>
                <title>geteltorito make CD firmware upgrades a breeze</title>
                <link>https://people.skolelinux.org/pere/blog/geteltorito_make_CD_firmware_upgrades_a_breeze.html</link>
                <guid isPermaLink="true">https://people.skolelinux.org/pere/blog/geteltorito_make_CD_firmware_upgrades_a_breeze.html</guid>
                <pubDate>Wed, 20 Apr 2022 11:50:00 +0200</pubDate>
                <description>&lt;p&gt;Recently I wanted to upgrade the firmware of my thinkpad, and
located the firmware download page from Lenovo (which annoyingly do
not allow access via Tor, forcing me to hand them more personal
information that I would like).  The
&lt;a href=&quot;https://support.lenovo.com/no/en/search?query=thinkpad firmware bios upgrade iso&amp;SearchType=Customer search&amp;searchLocation=Masthead&quot;&gt;download
from Lenovo&lt;/a&gt; is a bootable ISO image, which is a bit of a problem
when all I got available is a USB memory stick.  I tried booting the
ISO as a USB stick, but this did not work.  But genisoimage came to
the rescue.&lt;/p&gt;

&lt;P&gt;The geteltorito program in
&lt;a href=&quot;http://tracker.debian.org/cdrkit&quot;&gt;the genisoimage binary
package&lt;/a&gt; is able to convert the bootable ISO image to a bootable
USB stick using a simple command line recipe, which I then can write
to the most recently inserted USB stick:&lt;/p&gt;

&lt;blockquote&gt;&lt;pre&gt;
geteltorito -o usbstick.img lenovo-firmware.iso
sudo dd bs=10M if=usbstick.img of=$(ls -tr /dev/sd?|tail -1)
&lt;/pre&gt;&lt;/blockquote&gt;

&lt;p&gt;This USB stick booted the firmware upgrader just fine, and in a few
minutes my machine had the latest and greatest BIOS firmware in place.&lt;/p&gt;
</description>
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        <item>
                <title>Playing and encoding AV1 in Debian Bullseye</title>
                <link>https://people.skolelinux.org/pere/blog/Playing_and_encoding_AV1_in_Debian_Bullseye.html</link>
                <guid isPermaLink="true">https://people.skolelinux.org/pere/blog/Playing_and_encoding_AV1_in_Debian_Bullseye.html</guid>
                <pubDate>Sat, 16 Apr 2022 08:40:00 +0200</pubDate>
                <description>&lt;p&gt;Inspired by the recent news of
&lt;a href=&quot;https://slashdot.org/story/22/04/03/2039219/intel-beats-amd-and-nvidia-with-arc-gpus-full-av1-support&quot;&gt;AV1
hardware encoding support from Intel&lt;/a&gt;, I decided to look into
the state of AV1 on Linux today.  AV1 is a
&lt;a href=&quot;https://web.archive.org/web/20160618103850/http://www.digistan.org/open-standard:definition&quot;&gt;free
and open standard&lt;/a&gt; as defined by Digistan without any royalty
payment requirement, unlike its much used competitor encoding
H.264.  While looking, I came across an 5 year
&lt;a href=&quot;https://askubuntu.com/questions/1061908/how-to-encode-and-playback-video-with-the-av1-codec-on-bionic-beaver-18-04&quot;&gt;old
question on askubuntu.com&lt;/a&gt; which in turn inspired me to check out
how things are in Debian Stable regarding AV1.  The test file listed
in the question (askubuntu_test_aom.mp4) did not exist any more, so I
tracked down a different set of test files on
&lt;a href=&quot;https://av1.webmfiles.org/&quot;&gt;av1.webmfiles.org&lt;/a&gt; to test them
with the various video tools I had installed on my machine.  I was
happy to discover that AV1 decoding and playback worked with almost
every tool I tested:

&lt;table align=&quot;center&quot;&gt;
&lt;tr&gt;&lt;td&gt;mediainfo&lt;/td&gt;       &lt;td&gt;ok&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td&gt;dragonplayer&lt;/td&gt;    &lt;td&gt;ok&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td&gt;ffmpeg / ffplay&lt;/td&gt; &lt;td&gt;ok&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td&gt;gnome-mplayer&lt;/td&gt;   &lt;td&gt;fail&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td&gt;mplayer&lt;/td&gt;       &lt;td&gt;ok&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td&gt;mpv&lt;/td&gt;           &lt;td&gt;ok&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td&gt;parole&lt;/td&gt;        &lt;td&gt;ok&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td&gt;vlc&lt;/td&gt;           &lt;td&gt;ok&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td&gt;firefox&lt;/td&gt;         &lt;td&gt;ok&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td&gt;chromium&lt;/td&gt;        &lt;td&gt;ok&lt;/td&gt;&lt;/tr&gt;
&lt;/table&gt;

&lt;p&gt;AV1 encoding is available in Debian Stable from the aom-tools
version 1.0.0.errata1-3 package, using the aomenc tool.  The encoding
using the package in Debian Stable is quite slow, with the frame rate
for my 10 second test video at around 0.25 fps.  My 10 second video
test took 16 minutes and 11 seconds on my test machine.&lt;/p&gt;

&lt;p&gt;I tested by first running ffmpeg and then aomenc using the recipe
provided by the askubuntu recipe above.  I had to remove the
&#39;--row-mt=1&#39; option, as it was not supported in my 1.0.0 version.  The
encoding only used a single thread, according to &lt;tt&gt;top&lt;/tt&gt;.&lt;/p&gt;

&lt;blockquote&gt;&lt;pre&gt;
ffmpeg -i some-old-video.ogv -t 10 -pix_fmt yuv420p video.y4m
aomenc --fps=24/1 -u 0 --codec=av1 --target-bitrate=1000 \
  --lag-in-frames=25 --auto-alt-ref=1 -t 24 --cpu-used=8 \
  --tile-columns=2 --tile-rows=2 -o output.webm video.y4m
&lt;/pre&gt;&lt;/blockquote&gt;

&lt;p&gt;As version 1.0.0 currently have several
&lt;a href=&quot;https://security-tracker.debian.org/tracker/source-package/aom&quot;&gt;unsolved
security issues in Debian Stable&lt;/a&gt;, and to see if the recent
backport &lt;a href=&quot;https://tracker.debian.org/pkg/aom&quot;&gt;provided in
Debian&lt;/a&gt; is any quicker, I ran &lt;tt&gt;apt -t bullseye-backports install
aom-tools&lt;/tt&gt; to fetch the backported version and re-encoded the
video using the latest version.  This time the &#39;--row-mt=1&#39; option
worked, and the encoding was done in 46 seconds with a frame rate of
around 5.22 fps.  This time it seem to be using all my four cores to
encode.  Encoding speed is still too low for streaming and real time,
which would require frame rates above 25 fps, but might be good enough
for offline encoding.&lt;/p&gt;

&lt;p&gt;I am very happy to see AV1 playback working so well with the
default tools in Debian Stable.  I hope the encoding situation improve
too, allowing even a slow old computer like my 10 year old laptop to
be used for encoding.&lt;/p&gt;

&lt;p&gt;As usual, if you use Bitcoin and want to show your support of my
activities, please send Bitcoin donations to my address
&lt;b&gt;&lt;a href=&quot;bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&quot;&gt;15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&lt;/a&gt;&lt;/b&gt;.&lt;/p&gt;
</description>
        </item>
        
        <item>
                <title>Få en slutt på Digitale utslipp</title>
                <link>https://people.skolelinux.org/pere/blog/F__en_slutt_p__Digitale_utslipp.html</link>
                <guid isPermaLink="true">https://people.skolelinux.org/pere/blog/F__en_slutt_p__Digitale_utslipp.html</guid>
                <pubDate>Mon, 14 Mar 2022 22:00:00 +0100</pubDate>
                <description>&lt;p&gt;På onsdag sendte jeg følgende epost til Utdanningsetaten i Oslo
kommune (UDE).  Fikk beskjed om at min henvendelse har saksnummer
22/7559-1 i den
&lt;a href=&quot;https://www.oslo.kommune.no/etater-foretak-og-ombud/utdanningsetaten/postjournal-utdanningsetaten/&quot;&gt;offentlige
postjournalen til UDE&lt;/a&gt;.  Jeg er spent på hva slags respons jeg får.
Mistenker jo de fleste som sprer sine nettsideleseres
personopplysninger til utlandet ikke har tenkt så nøye igjennom hva de
gjør, og at det er håp om at de tenker seg litt nøyere om hvis de blir
klar over problemstillingen.  Vet du noen som burde få tilsvarede
beskjed og spørsmål?  Kanskje du kan sende dem en epost.  Hvis alle
bidrar blir det kanskje litt bedre.&lt;/p&gt;

&lt;blockquote&gt;
&lt;p&gt;To: postmottak (at) osloskolen.no
&lt;br&gt;Subject: Digitale utslipp fra osloskolens nettsider&lt;/p&gt;

&lt;p&gt;Hei.&lt;/p&gt;

&lt;p&gt;Jeg ser at osloskolens nettsider har digitale utslipp av
personopplysninger til Google, Facebook og andre, blant annet omtalt
på &amp;lt;URL: &lt;a href=&quot;https://aktuelt.osloskolen.no/personvernerklaring-for-osloskolen/informasjonskapsler/&quot;&gt;https://aktuelt.osloskolen.no/personvernerklaring-for-osloskolen/informasjonskapsler/&lt;/a&gt;
&gt;.&lt;/p&gt;

&lt;p&gt;&amp;lt;URL: &lt;a href=&quot;https://webbkoll.dataskydd.net/&quot;&gt;https://webbkoll.dataskydd.net/&lt;/a&gt; &gt; kan være et nyttig verktøy for å holde øye med utslippsomfanget på ulike sider.&lt;/p&gt;

&lt;p&gt;Kanskje det er en ide å gjøre noe med det, jamfør &amp;lt;URL: &lt;a href=&quot;https://www.digi.no/artikler/debatt-det-enkleste-tiltaket-er-a-skru-av-google-analytics/517378&quot;&gt;https://www.digi.no/artikler/debatt-det-enkleste-tiltaket-er-a-skru-av-google-analytics/517378&lt;/a&gt; &gt;?&lt;/p&gt;

&lt;p&gt;Et alternativ til Google Analytics kan være en lokalt installert
utgave av &amp;lt;URL:
&lt;a href=&quot;https://matomo.org/&quot;&gt;https://matomo.org/&lt;/a&gt; &gt;.  Den og flere
andre alternativer kan finnes via
&amp;lt;URL: &lt;a href=&quot;https://www.digi.no/artikler/sverige-vil-skrote-amerikansk-skytjeneste-her-er-alternativene/516223?key=5QsV0wRG&quot;&gt;https://www.digi.no/artikler/sverige-vil-skrote-amerikansk-skytjeneste-her-er-alternativene/516223?key=5QsV0wRG&lt;/a&gt; &gt;
på bakgrunn av at svenske myndigheter har innsett at dagens praksis
nok er både lite lur og ulovlig.  Der henger Norge litt etter, men
osloskolen har her mulighet til å være litt i forkant. :)&lt;/p&gt;

&lt;p&gt;Fint om dere kan gi beskjed hvilket saksnummer denne henvendelsen får i
offentlig postjournal når den er mottatt.&lt;/p&gt;

&lt;/blockquote&gt;

&lt;/p&gt;Flere og flere innser at slik spredning av personopplysninger er
ugreit.  Det har pågått i mange år.  Ser jeg blogget
&lt;a href=&quot;https://people.skolelinux.org/pere/blog/Det_er_jo_makta_som_er_mest_s_rbar_ved_massiv_overv_kning_av_Internett.html&quot;&gt;første
gang om Google Analytics i 2013&lt;/a&gt; og
&lt;a href=&quot;https://people.skolelinux.org/pere/blog/Snurpenot_overv_kning_av_sensitiv_personinformasjon.html&quot;&gt;analyserte
omfanget i 2015&lt;/a&gt;, men det er et langt lerret å bleke.&lt;/p&gt;

&lt;p&gt;Som vanlig, hvis du bruker Bitcoin og ønsker å vise din støtte til
det jeg driver med, setter jeg pris på om du sender Bitcoin-donasjoner
til min adresse
&lt;b&gt;&lt;a href=&quot;bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&quot;&gt;15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&lt;/a&gt;&lt;/b&gt;.
Merk, betaling med bitcoin er ikke anonymt. :)&lt;/p&gt;
</description>
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