Video distribution in the classroom

We have a computer room in our local university, ind it’s quite bussy. The main problem it became (this is another story) too long to be usable and there was a strong demand for the screencast view right on the student’s workplace. Yes we do use beamers, but the view was too small to dead the text on the screen.

And so the project was born. There is single seat where the view originates and multiple locations where it should be visible. The system must be easily expandable and upgradeable, no vendor lock-ins. All the points in the systems should be easily adjustable and replaceable.

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Small problem with CFD simulations

Just a tiny hole in the mesh may create a great mess.

The initial wind speed is 10 m/s, laminar aiflow. And the result is small F15+ class tornado int he Fujita scale.

Messing with PHP-ODT

I’m working oh hobby project on a free time, and one of the tasks here is to generate ODT file, containing output from the database. The output library i’ve chosen is PHP-ODT. It’s kind of basic, but allows to create ODT documents on the fly.

And now, lessons learned

Allways provide file size.

This code will create corrupt file, according to LibreOffice: The correct code is:

 header(“Content-Description: File Transfer”);
header(“Content-Type: application/vnd.oasis.opendocument.text”);
header(“Content-Disposition: attachment; filename=\”” . $ODTFile .”\”” );
readfile($ODTtmpFile);

 header(“Content-Description: File Transfer”);
header(“Content-Type: application/vnd.oasis.opendocument.text”);
header(‘Content-Length: ‘ . filesize($ODTtmpFile));
header(“Content-Disposition: attachment; filename=\”” . $ODTFile .”\”” );
readfile($ODTtmpFile);

It is possible to add hierarchical styles

Not in the base code yet

$pStyleDate = new ParagraphStyle(‘revDate’);

$pStyleDateStrike = new ParagraphStyle(‘revDate-strike’);
$pStyleDateStrike->setAsChild(‘revDate’);

It is possible to add text decorations in the paragraph level

Again, not in the base code yet:

$pStyleDateStrike->setLineThrough(StyleConstants::SINGLE);

It is possible to merge cells in the table

Well, not in the base code and horizontally only:

$hSpan=array(“”,””,””);

$cRow = array($hSpan,$pRev,$pDate,$pMemo);
$table->addRows(array($cRow));

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My favourite X sceensaver is …

Substrate

Captured with  ‘$ sleep 120 ; xwd -root -out full-screen.xwd

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Replacement belt for Proxxon KS 230 table saw

The belt is B45MXL – MXL (0.08″) pitch, 45 -teeth, 10 mm width.

It will cost around $15 per 10 pack on if you know the pitch and length, or starting $15 for a single one, if you buy it as “KS 230 replacement belt”, part number  27006/57.

 

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The Power of Pipes

Okay guys, the log if filling with

sshd[20117]: Invalid user pi from 142.93.118.186 port 50416
sshd[20117]: input_userauth_request: invalid user pi [preauth]
sshd[20117]: Received disconnect from 142.93.118.186 port 50416:11: Bye Bye [preauth]
sshd[20117]: Disconnected from 142.93.118.186 port 50416 [preauth]
sshd[20119]: Invalid user cubie from 5.189.227.161 port 39772
sshd[20119]: input_userauth_request: invalid user cubie [preauth]
sshd[20119]: Received disconnect from 5.189.227.161 port 39772:11: Bye Bye [preauth]
sshd[20119]: Disconnected from 5.189.227.161 port 39772 [preauth]
sshd[20121]: Invalid user guest from 208.68.37.169 port 42858

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Postfix and virtual SMTP users

Short how-to use the save virtual users both for receiving emails via IMAPS, and sending via SMTP, or just rants for myself:

Source for the ideas and setup

/etc/postfix/main.cf must contain:
smtpd_sasl_local_domain =
smtpd_sasl_auth_enable = yes

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PCB manufacturing in China

So, here it comes. I need a small, pretty looking PCB for the infrared switcher.

It took 3 hours to validate the order, almost 25 hours to make the PCBs and almost 2 days to announce them delivery ready.

To be continued, once they arrive 🙂

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Migration hell

After a regular hardware failure the entire site was migrated to a more stable location.

Well, there was a lot of customization done and the new APIs appeared in the last .. 12 (wait, no way!)  years.

As allways, be sure you have your backups. they are up to date and are easily accessible once you need them.

Infrared switcher for the auditorium. Part 1

Sometimes I find myself in awkward situations.

Some time ago we have installed a video duplication system in one of auditoriums. It is based on the HDMI backbone and some active equipment, like splitters and media converters.

It has single video injection point, where different sources can be selected. Source switching is made using KD-S4X1 switch from Key Digital.

One small problem is the entire installation must be concealed, while the switch is controlled with a button on the case and the IR remote. It has also no means of displaying the output, except a LED per active channel.

And so the Project was born: place a push button anywhere and replay the sequence on the IR LED inside the enclosure. Just to be sure, an Read the rest of this entry »

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