Petter Reinholdtsen

Entries from September 2010.

My first perl GUI application - controlling a Spykee robot
2010-09-01 21:00

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.

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:

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();

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. :).

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 the NUUG wiki for those that want to check back later to find it.

Tags: english, nuug, robot.
Some notes on Flash in Debian and Debian Edu
2010-09-04 10:10

In the Debian popularity-contest numbers, the adobe-flashplugin package the second most popular used package that is missing in Debian. The sixth most popular is flashplayer-mozilla. This is a clear indication that working flash is important for Debian users. Around 10 percent of the users submitting data to popcon.debian.org have this package installed.

In the report written by Lars Risan in August 2008 («Skolelinux i bruk – Rapport for Hurum kommune, Universitetet i Agder og stiftelsen SLX Debian Labs»), one of the most important problems schools experienced with Debian Edu/Skolelinux was the lack of working Flash. A lot of educational web sites require Flash to work, and lacking working Flash support in the web browser and the problems with installing it was perceived as a good reason to stay with Windows.

I once saw a funny and sad comment in a web forum, where Linux was said to be the retarded cousin that did not really understand everything you told him but could work fairly well. This was a comment regarding the problems Linux have with proprietary formats and non-standard web pages, and is sad because it exposes a fairly common understanding of whose fault it is if web pages that only work in for example Internet Explorer 6 fail to work on Firefox, and funny because it explain very well how annoying it is for users when Linux distributions do not work with the documents they receive or the web pages they want to visit.

This is part of the reason why I believe it is important for Debian and Debian Edu to have a well working Flash implementation in the distribution, to get at least popular sites as Youtube and Google Video to working out of the box. For Squeeze, Debian have the chance to include the latest version of Gnash that will make this happen, as the new release 0.8.8 was published a few weeks ago and is resting in unstable. The new version work with more sites that version 0.8.7. The Gnash maintainers have asked for a freeze exception, but the release team have not had time to reply to it yet. I hope they agree with me that Flash is important for the Debian desktop users, and thus accept the new package into Squeeze.

Tags: debian, debian edu, english, multimedia, video, web.

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