<link>http://people.skolelinux.org/pere/blog/</link>
<atom:link href="http://people.skolelinux.org/pere/blog/index.rss" rel="self" type="application/rss+xml" />
+ <item>
+ <title>My first perl GUI application - controlling a Spykee robot</title>
+ <link>http://people.skolelinux.org/pere/blog/My_first_perl_GUI_application___controlling_a_Spykee_robot.html</link>
+ <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/My_first_perl_GUI_application___controlling_a_Spykee_robot.html</guid>
+ <pubDate>Wed, 1 Sep 2010 21:00:00 +0200</pubDate>
+ <description>
+<p>This evening I made my first Perl GUI application. The last few
+days I have worked on a Perl module for controlling my recently
+aquired Spykee robots, and the module is now getting complete enought
+that it is possible to use it to control the robot driving at least.
+It was now time to figure out how to use it to create some GUI to
+allow me to drive the robot around. I picked PerlQt as I have had
+positive experiences with the Qt API before, and spent a few minutes
+browsing the web for examples. Using Qt Designer seemed like a short
+cut, so I ended up writing the perl GUI using Qt Designer and
+compiling it into a perl program using the puic program from
+libqt-perl. Nothing fancy yet, but it got buttons to connect and
+drive around.</p>
+
+<p>The perl module I have written provide a object oriented API for
+controlling the robot. Here is an small example on how to use it:</p>
+
+<p><pre>
+use Spykee;
+Spykee::discover(sub {$robot{$_[0]} = $_[1]});
+my $host = (keys %robot)[0];
+my $spykee = Spykee->new();
+$spykee->contact($host, "admin", "admin");
+$spykee->left();
+sleep 2;
+$spykee->right();
+sleep 2;
+$spykee->forward();
+sleep 2;
+$spykee->back();
+sleep 2;
+$spykee->stop();
+</pre></p>
+
+<p>Thanks to the release of the source of the robot firmware, I could
+peek into the implementation at the other end to figure out how to
+implement the protocol used by the robot. I've implemented several of
+the commands the robot understand, but is still missing the camera
+support to make it possible to control the robot from remote. First I
+want to implement support for uploading new firmware and configuring
+the wireless network, to make it possible to bootstrap a Spykee robot
+without the producers Windows and MacOSX software (I only have Linux,
+so I had to ask a friend to come over to get the robot testing
+going. :).</p>
+
+<p>Will release the source to the public soon, but need to figure out
+where to make it available first. I will add a link to
+<a href="http://wiki.nuug.no/grupper/robot/">the NUUG wiki</a> for
+those that want to check back later to find it.</p>
+</description>
+ </item>
+
<item>
<title>Forslag i stortinget om å stoppe elektronisk stemmegiving i Norge</title>
<link>http://people.skolelinux.org/pere/blog/Forslag_i_stortinget_om____stoppe_elektronisk_stemmegiving_i_Norge.html</link>
</description>
</item>
- <item>
- <title>No hardcoded config on Debian Edu clients</title>
- <link>http://people.skolelinux.org/pere/blog/No_hardcoded_config_on_Debian_Edu_clients.html</link>
- <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/No_hardcoded_config_on_Debian_Edu_clients.html</guid>
- <pubDate>Mon, 9 Aug 2010 20:15:00 +0200</pubDate>
- <description>
-<p>As reported earlier, the last few days I have looked at how Debian
-Edu clients are configured, and tried to get rid of all hardcoded
-configuration settings on the clients. I believe the work to be
-mostly done, and the clients seem to work just fine with dynamically
-generated configuration.</p>
-
-<p>What is the point, you might ask? The point is to allow a Debian
-Edu desktop to integrate into an existing network infrastructure
-without any manual configuration.</p>
-
-<p>This is what happens when installing a Debian Edu client here at
-the University of Oslo using PXE. With the PXE installation, I am
-asked for language (Norwegian Bokmål), locality (Norway) and keyboard
-layout (no-latin1), Debian Edu profile (Roaming Workstation), if I
-accept to reformat the hard drive (yes), if I want to submit info to
-popcon.debian.org (no) and root password (secret). After answering
-these questions, the installer goes ahead and does its thing, and
-after around 50 minutes it is done. I press enter to finish the
-installation, and the machine reboots into KDE. When the machine is
-ready and kdm asks for login information, I enter my university
-username and password, am told by kdm that a local home directory has
-been created and that I must log in again, and finally log in with the
-same username and password to the KDE 4.4 desktop. At no point during
-this process did it ask for university specific settings, and all the
-required configuration was dynamically detected using information
-fetched via DHCP and DNS. The roaming workstation is now ready for
-use.</p>
-
-<p>How was this done, you might wonder? First of all, here is the
-list of things that need to be configured on the client to get it
-working properly out of the box:</p>
-
-<ul>
-<li>IP address/netmask and DNS server.</li>
-<li>Web proxy URL.</li>
-<li>LDAP server for NSS directory information (user, group, etc).</li>
-<li>Kerberos server for PAM password checking.</li>
-<li>SMB mount point to access the network home directory. (*)</li>
-<li>Central syslog server to send syslog messages to. (*)</li>
-<li>Sitesummary collector URL to submit info to central server. (*)</li>
-</ul>
-
-<p>(Hm, did I forget anything? Let me knew if I did.)</p>
-
-<p>The points marked (*) are not required to be able to use the
-machine, but needed to provide central storage and allowing system
-administrators to track their machines. Since yesterday, everything
-but the sitesummary collector URL is dynamically discovered at boot
-and installation time in the svn version of Debian Edu.</p>
-
-<p>The IP and DNS setup is fetched during boot using DHCP as usual.
-When a DHCP update arrives, the proxy setup is updated by looking for
-http://wpat/wpad.dat and using the content of this WPAD file to
-configure the http and ftp proxy in /etc/environment and
-/etc/apt/apt.conf. I decided to update the proxy setup using a DHCP
-hook to ensure that the client stops using the Debian Edu proxy when
-it is moved outside the Debian Edu network, and instead uses any local
-proxy present on the new network when it moves around.</p>
-
-<p>The DNS names of the LDAP, Kerberos and syslog server and related
-configuration are generated using DNS information at boot. First the
-installer looks for a host named ldap in the current DNS domain. If
-not found, it looks for _ldap._tcp SRV records in DNS instead. If an
-LDAP server is found, its root DSE entry is requested and the
-attributes namingContexts and defaultNamingContext are used to
-determine which LDAP base to use for NSS. If there are several
-namingContexts attibutes and the defaultNamingContext is present, that
-LDAP subtree is used as the base. If defaultNamingContext is missing,
-the subtrees listed as namingContexts are searched in sequence for any
-object with class posixAccount or posixGroup, and the first one with
-such an object is used as the LDAP base. For Kerberos, a similar
-search is done by first looking for a host named kerberos, and then
-for the _kerberos._tcp SRV record. I've been unable to find a way to
-look up the Kerberos realm, so for this the upper case string of the
-current DNS domain is used.</p>
-
-<p>For the syslog server, the hosts syslog and loghost are searched
-for, and the _syslog._udp SRV record is consulted if no such host is
-found. This algorithm works for both Debian Edu and the University of
-Oslo. A similar strategy would work for locating the sitesummary
-server, but have not been implemented yet. I decided to fetch and
-save these settings during installation, to make sure moving to a
-different network does not change the set of users being allowed to
-log in nor the passwords required to log in. Usernames and passwords
-will be cached by sssd when the user logs in on the Debian Edu
-network, and will not change as the laptop move around. For a
-non-roaming machine, there is no caching, but given that it is
-supposed to stay in place it should not matter much. Perhaps we
-should switch those to use sssd too?</p>
-
-<p>The user's SMB mount point for the network home directory is
-located when the user logs in for the first time. The LDAP server is
-consulted to look for the user's LDAP object and the sambaHomePath
-attribute is used if found. If it isn't found, the home directory
-path fetched from NSS is used instead. Assuming the path is of the
-form /site/server/directory/username, the second part is looked up in
-DNS and used to generate a SMB URL of the form
-smb://server.domain/username. This algorithm works for both Debian
-edu and the University of Oslo. Perhaps there are better attributes
-to use or a better algorithm that works for more sites, but this will
-do for now. :)</p>
-
-<p>This work should make it easier to integrate the Debian Edu clients
-into any LDAP/Kerberos infrastructure, and make the current setup even
-more flexible than before. I suspect it will also work for thin
-client servers, allowing one to easily set up LTSP and hook it into a
-existing network infrastructure, but I have not had time to test this
-yet.</p>
-
-<p>If you want to help out with implementing these things for Debian
-Edu, please contact us on debian-edu@lists.debian.org.</p>
-
-<p>Update 2010-08-09: Simon Farnsworth gave me a heads-up on how to
-detect Kerberos realm from DNS, by looking for _kerberos TXT entries
-before falling back to the upper case DNS domain name. Will have to
-implement it for Debian Edu. :)</p>
-</description>
- </item>
-
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