tim.jagenberg.info » Tinkering

Wireless Keyboard Range Extension

Tim — Sun, 16 Jan 2011 18:58:09 +0000

For a long time the sometimes shaky wireless connection of my “couch keyboard” had been bothering me, when I realised that a few sheets of aluminium foil placed behind the antenna improved the situation considerably. Yesterday I finally sat down and solved the problem for good:

The simple spherical mirror made out of cardboard and a layer of aluminium foil with the receiver in its focal point works perfectly. It extended the range of my keyboard beyond my balcony (~ +60%).

Cheers
Tim

The Home Media Server

Tim — Fri, 17 Jul 2009 17:38:13 +0000

Check out the final result of the Home Media Server project:

Low Power Home Media Server

Tim — Sat, 04 Jul 2009 13:28:25 +0000

So far I have been using my big quadcore machine as a desktop and as a server at the same time. With the Q6600 processor with four cores, it was hardly doing anything for the vast majority of the time. As I also use it as my digital video recorder (thanks to MythTV) it has been running 24/7 using quite a bit of power. The latest energy bill and a recent discussion in my group of friends on how to reduce consumption of resources led me to change this setup.
Out of curiosity I had been looking into the Mini-ITX formfactor before and thought it would be the right way to go. After a few evenings of research I found the perfect mainboard for my needs. An Intel Atom based Mini-ITX board with integrated powersupply and completely passive cooling (Intel D945GSEJT). Combined with a slow spinning 1GB harddrive (Samsung EcoGreen HD103UI) this server would hardly emit any noise.

I ordered all components online and when I got the last part (the mainboard of course ) putting everything together was just a thing of minutes. Installing a console Ubuntu system is quite a routine for me and only took a few moments. Of course installing all the services that had previously been running on my desktop took some more time:

NFS Server for my files
Digital TV (DVB-S) using MythTV
SqueezeCenter for the SqueezeBox in my sleepingroom
E-Mail server using fetchmail and DOVECOT IMAP
Subversion server via SSH
Apache2 webserver providing the following web-interfaces
MythWeb for managing my recordings remotely
RoundCube for IMAP
PHPMyAdmin for MySQL maintenance
WebSVN for Subversion repository browsing
Munin for systemÂ statistics

So far everything proved to run reliable and best of all: The whole shebang only uses about 20W compared to 160W the desktop is using. The next thing I’ll have to do is to create a simple enclosure as I am not convinced by the Mini-ITX cases you can buy off the shelf.

IR Webcam Modification

Tim — Sat, 18 Aug 2007 22:36:59 +0000

Following some tutorials (grynx, hoagieshouse) I modified my webcam (Philips PCVC740K) to use near infrared light, which is invisible to the human eye.
The two basic steps are to remove the original IR blocking filter from the backside of the lens assembly and replace it with a few layers of unexposed but developed color negatives as IR pass filter.
The PCVC740K uses the ICX098AK CCD chip with the sensitivity documented in the datasheet.
The first two pictures show various things in visible light and in near IR, the two last pictures show my wrist and arm, exposing bloodvessels.

the vacuum worked perfectly

Tim — Thu, 10 Aug 2006 17:18:20 +0000

Hiho …

After 24hrs in the vacuum bag, the first wing just looks great! It’s really stiff and strong, I just tested it for about 4g loading without any noises or anything. (a crackling noise is a first indication for overstressing the compound material)

The chord of the wing still is larger than the final wing, as the trailing edge is excess material and will be cut to the final shape later.

Cheers,
Tim (smiling)!

exams and a new rc-plane again

Tim — Wed, 09 Aug 2006 13:07:22 +0000

Hi everyone,

Yea, I know I haven’t updated in a while, so I’m doing this right now.
Aside the work for my assignment I’m, as always, learning for some upcoming exams, if nothing fails, these are my last ones!

As my last rc-plane got damaged during the last launch I’m working on a new one. Basically the same flying-plank concept, but this time with higher wingspan and thus higher aspect ratio. Another novelty will be a small electric motor (brushless outrunner) with a folding prop, to assist the time in between thermals.

The design of the wings is different as well, this time I cut a styro-foam core (with Joern’s help ) which I’ll cover with 1mm obeche veneer. First I tried using the rest of the styro and 36kg in water bottles to press the veneer to the core, while the epoxy was curing, but this didn’t work well in the strongly curved areas around the leading edge.

For some time I thought about using a vacuum system for the pressing, so this time I decided to finally build such a system. All I need is a airtight bag, to put the wing and veneer in and a vacuum-pump to evacuate the bag.
For the bag I got me some 0.09mm PVC foil which I then sealed with a hot wire on a wooden bar, pressing it to a flat surface.

To create the vacuum, I used a cheap aquarium-air-pump, reversing the tubes on the inside, measuring the pressure-difference with a small tube, hung on the wall of my kitchen with the open bottom end in a bottle of water. The height the water rises when a vacuum is created on the other end is proportional to the pressure-difference, with 1m corresponding to roughly 0,1 athmospheres. This showed a sufficient pressure-difference of about 0,3 athmospheres while the pump was still rather quiet.

On the last two pictures you can see how nicely this works. But these were just preliminary tests, without the epoxy. The real test will be tonight!

I’ll post some further update once I see how the final test worked.
Cheers, everybody!

Tim — Sat, 01 Apr 2006 20:39:36 +0000

Once more some rc-plane videos. This time it’s Martin and JÃ¶rn flying. When I got ready, it started to pour down.
– Martin Start
– Martin Flight
– Joern Start
– Joern Flight

the first flight!

Tim — Sun, 19 Mar 2006 17:23:53 +0000

The perfect day for a first flight, calm wind and blue sky!
After a bit of adrenalin the Plank2 turns out to handle quite well. The first few flights with the rubber went well, and I even managed to catch some thermals, staying up in the air for nearly 5 mins.

And some video as well: one of the first flights
Next I’ll get me a longer rubber, to get to a higher altitude from the begining, giving me more time to fearch thermals.

Cheers everyone,
Tim.

the flying plank

Tim — Mon, 27 Feb 2006 12:54:02 +0000

Aside learning for the upcoming tests, I’m currently working on a new flying plank. After the successful tests with the first 9hrs prototype, I changed the design of the fuselage to be more rough and provide more space for trimming. As the rudder turned out to be too small, I increased the size quite a bit and added the option to quickly change the whole part.

This time I also chose a thinner airfoil (JWL065) adding the need for a spar. To get a smooth surface, I’ll cover the wing with adhesive foil.

Read more once I managed to test this guy.

Cheers everyone,
Tim.

non-destructive testing

Tim — Thu, 09 Feb 2006 17:28:59 +0000

Hey there …

To let you know what I’m doing at the uni, I posted a few pictures of the laboratories for non-destructive testing.

This is me, pictured by an infraredcamera; I guess those structures at the side of my forehead are veins.

These are the inner structures of my mobile-phone, x-rayed from behind.

The left picture shows a standard photo of the nosepart of some wing. The right shows the same part in ultrasound exited thermography, where the defect (a small crack between two rivets) shows up in white because it radiates heat.

Aside this we are preparing for the final presentation of our airliner-design and the last few days I started preparing for the tests coming up in the next months.

G’day everyone,
Tim.

rc-planes again

Tim — Mon, 12 Dec 2005 11:00:43 +0000

After finally managing to get me some basic tools, I started to build rc-planes again. The first try was a small only-wing hang-glider (similar to “Little Plank”).

After a test flight at the “GrÃ¼ner Heiner” it turned out that the vertical stabiliser is quite a bit too small. But the trim calculations were pretty well and it flew right out of my hand, no further trim needed.
Now I’m planning the successor with a bigger vertical fin and a longer and stronger nose (after a few hard landings the nose broke off).

Leaving Sydney

Tim — Tue, 01 Jun 2004 15:00:00 +0000

Afer over half a year living and (very succesfully) working in Sydney I left the city I fell in love with. With a short hop to Melbourne I start the backpacking-season.
Sitting at the gate, I’m sipping a “Tall Long Black” (a small one would have been a “Short Long Black” that happens when americans don’t care about local specialities (Starbucks)).
Guess this is a fine time to recapitulate. The things I liked most about Sydney were it’s multicultural lifestyle and it’s live-music scene (Cheers to all the Ska-people and “Waiting For Guinnes”).
The major small things I’ll be missing are the nice walks through the park to the uni, the beatiful glimpses at Sydney Skyline in the sunset from Glebe and the probably friendliest pizzeria around the corner (Boost Cafe Glebe).
In this rather short time I met so many nice people, had heaps of interesting conversations and made lots of new friends (hope I’ll be able to stay in contact with them).
Working at the Uni Sydney was a pleasure and interesting. I enjoyed helping the firstsemesters with their catapult and like to hear what hapened to the hovering platform.
The talks with profs, former students and the staff were really inspiring and I hope I can set up my own small workshop to work on my ideas.

Well, enought of the past, I’ll be boarding any moment.
On the road again, taking the long way home.

Thanks everybody for this nice time,
Tim.

Niceeee …

Tim — Mon, 23 Jun 2003 11:00:00 +0000

New homepage is up and running!
Even if you don’t see too many changes, all the structure behind what u see has changed!
The last few days i completly rewrote the whole page using PHP and a mySQL database.
As there’s quite a lot of data from the old version, it’ll take some time to add all the old images and texts to this new version.

Greets and bye, Tim.

Merry Christmas and a happy new year!

Tim — Sun, 01 Dec 2002 11:00:00 +0000

As we have christmas-holidays right now, i found some time to update my page.

The last few weeks / months of university were quite busy. There was really few time to relax or even party! So I’m doing that right now. Last week i went to a concert of ‘Open Season’ and ‘The Peacocks’ at Stuttgart, after that I had a strange evening with a nice girl at the Club ‘Le Fonque’, the ‘evening’ ended at 800, returning home with the first connection. Last week, my parents, my grandma from Hamburg and me celebrated christmas, gathering, having lots of unhealthy food and even more fun.
Before christmas, my father and me exchanged the old gas tank of my Samurai, which took us three days! After christmas we started to prepare my new room in the house, by clearing it and painting the walls.
As soon as we built the tables and other stuff, I’ll move. After 2 years of cellar, I’m quite happy to see the sunlight again! (Don’t think my parents stuffed me in the cellar! I chose to do that and they told me 2 years ago I was crazy because of that, maybe I was!)

Right now I’m returning home from a concert of ‘HISS’ at the ‘Schlesinger Int.’. Was really great! Some kind of mixture between Rock and Polka with German lyrics.