Diskokugel Progress

Sunday, January 23rd, 2011

My work for the Computerspielemuseum (video game museum) is done, so I started right away to work on my Diskokugel again. Theres a few updates form the last time I posted on this:

I decided to stay with the wireframe as it is, not filling the blanks in between. I think, looking into the thing is just as mindblowing as looking at it, especially because I came up with a solution for the resonating body of the speakers: chrome christmas baubles! Since it was the time of the year I found some made of plastic in just the right size to fit the speakers. Another problem solved.

Kitsch is the solution...

Secondly I sat down looking for a solution to keep the whole ball stable and to attach the electronics to. The surface of the ball has 12 “blank” spots (the centers of the pentagons of the soccer ball pattern). Here, something could be attached to connect to a support inside. So I was looking for a body with 12 corners, an icosahedron. It took me only about three ours to solder this model:

There she is

Quite beautiful, isn’t it? The plan is, to have either a shim or a nut on each corner and to connect to the “surface” via thread bars. The circuit boards will be attached to the edges, making it a kind of star floating within the ball with lots of wires leading to the surface (I will probably wind them around the bars).

I replaced the corners with nuts. Two thread bars sticking in.

Problem right now is, to construct this support in a manner that actually will carry the load. the thing on the picture is soldered with regular solder and won’t last. I’d have to at least braze or weld the stuff. A first attempt to braze it at home failed miserably, so I’ll have to look for help somewhere.

PD Video Player with Sound

Saturday, November 13th, 2010

I had the idea to build a kind of solid state video player using Linux and Puredata with an Arduino. The educated reader might ask “Why PD?” and, of course, is right. The simple answer is: Because I can and its easy.

I take the latter back. When I came up with this I had totally ignored, that Puredata/Gems Pix_Film object doesn’t play sound. This means, video and sound have to be played in separate players and then be synced. Some research in PDs list gave me an example I started working with and I was partially successful. Video and sound sync well with a [vline~] but with high resolutions the sound glitches. This can be reduced by trying different video codecs (motionjpg is supposed to work pretty well) but still I wasn’t able to play 1280×1024 videos without the sound dropping sometimes. I didn’t have this problem using the [pix_buffer] object, but this way the video is loaded into the RAM uncompressed, which takes up tons of space and limits the possible length of videos loaded/used. This was on my MacBook with 2x2GHz and an onboard Intel 9400m graphics card. I will try it on Linux in the next days, lets see, if it works better.

However, I expect no wonders and theres no sense in building a solid state video player that needs hardware this expensive (and energy intensive). I want to use one of these fit-pcs, loving their small design and power consumption. For them to work with videos of that resolution I need to use their hardware acceleration, which might prove difficult on Linux (I heard nothing good about the support of intels gma500) and even worse when relying on PD/Gem, which uses OpenGL to render video. So the plan now is to use a common video player like VLC or mplayer and remote control it via network/localhost. That should take care of the hardware acceleration and still make use of the serial interface and interaction possibilities of PD. Stay tuned…

Pure Data Video Player with Audio Sync

This patch syncs video and audio



Solar Collect Call by Thomas Saraceno

Saturday, November 6th, 2010

A friend from Studio Saraceno called because some solar panel mirrors had to be assembled here in Berlin. Those are actually large frames with solar panel foil behind a glass coated with some reflecting film. Inside the frame is a battery thats loaded by the solar foil and provides power to load cell phones and such. Looks quite nice but the efficiency is greatly reduced by the fact that the foil has to laminated to be applied to the frame without folding and breaking. The film on the glass further reduces the amount of UV light that reaches the foil. since we worked indoors there was no way to do some measurement.

the solar foil

the mirror

To apply that film they extra sent the stuff from Frankfurt to Berlin, but apparently the guys who did it here didn’t do their job too well, judging from the scratches on the glass and dirt behind the film. There seems to be some kind of magic to it, since even the manufacturer of the film doesn’t seem to know how to handle this.

Tech Stuff

Wednesday, November 3rd, 2010

My current task is to build some stuff for the Computerspiele Museum. Thats not as exciting as it sounds, however it totally fits to the stuff I’ve been doing over the last months. An interface/video player is to be controlled using a joystick while LEDs are lit correspondingly. Again, Christian was very helpful here and provided me with a basic idea, how to build this. The plan changed various times since at first I was told I had to work with 12V LEDs, no one knows why. That sounded easy at first because I thought I could simply take those LED clusters that replace common halogen lights. But it turned out that most of them are not dimmable, unless you take really expensive ones (~€ 30,-). So now I use 3W ones on a heat sink. looks quite nice.

I even found a shop to buy arcade hardware such as knobs, joysticks etc. Sure there’ll be more fun with that soon :-)

to illustrate the current affairs

Back to School (on my own)

Monday, October 18th, 2010

Working with Christian on my “Diskokugel” I decided I need to earn more about the basic electronics behind it. In fact, since I started with the project I have already learned more about it than in my electronics classes at the university, but it all remains some kind of esoteric half knowledge when one knows nothing about the rules behind it. So I started to teach myself intensely, reading and doing tests at home.

I found an open book project that has written a complete compendium for electronics education in a way that is totally understandable and their website even provides tests and exercises to check on your knowledge. Awesome!

PD and Arduino

Monday, October 18th, 2010

I explored some ways to use PD to communicate with an Arduino. There are wo ways to interact with an Arduio from PD: serial communication via the [comport] object and controlling the Arduino directly with [pduino] using the firmata firmware.

[comport] simply sends and receives serial messages. I found it a little difficult to convert those messages into the right format as to understand and further process them. The PD help file isn’t exactly helpful to that extend, but I found a patch called ArduinoPDMessageSystem that makes sense of the serial messages, even though I haven’t understood every objects function there yet.

So far, I have managed to send messages to the Arduino to interface a HCF4094 shift register controlling 8 LEDs. I use the same register to control my “Diskokugel”, so heres for the next step to its completion :-)

Crazy AV Machines Workshop

Monday, October 4th, 2010

The past week I participated in a PD workshop run by Oscar Martin and Luca Carruba at NK gallery. The workshop lasted one week and ended with a collaborate performance where all participants used their patches made during the workshop. I can’t tell you how that turned out because unfortunately I had to leave two days early to finish another job. However, the workshop was quite inspiring. Oscar and Luca rushed us through the possibilities of the software so fast that I imagine it hard for an actual newbie to keep up. For me it was quite informative, especially since I had my own agenda, wanting to know how to communicate with an Arduino with PD as means of an interface.

I’ve worked with Max/MSP and VVVV before and also had a look at JMax and PD back in 2002. PD has evolved a lot since then and since it is a piece of true open source software it has all my sympathies. The community is active and I´ve found the mailing list extremely patient and useful.

My Tammes Problem

Monday, August 30th, 2010

After a two weeks pause I urgently needed, I got back to my problem of the equally distributed circles on a sphere. Some more research revealed that it is a problem yet unsolved. It is called Tammes Problem, a specialization of the Thomson Problem. Wikipedia shows some solutions, which is quite convenient. I still struggle with the practical application though…

Diskokugel 0.2

Friday, August 13th, 2010


Ok, so after 4 days of soldering witness the new version of “Diskokugel” with speakers attached. I am quite satisfied with the looks.

out now: 0.2beta

out now: 0.2beta

The longer you look, the more patterns you'll find...

The longer you look, the more patterns you'll find...

The wireframe. Withe the background cancelled out it's more comprehensible.

The wireframe. With the the background cancelled out it's more comprehensible.

Doing all the soldering I had plenty of time to contemplate on the design so far:
The wireframe has quite a few disadvantages considering the further construction. It is not very exact, not very stable and I haven’t figured out a way to construct and attach proper enclosures for the individual speakers to prevent the acoustic cancelation of lower frequencies.
I could fill the whole thing with polyurethane foam and carve it out like a pumpkin, but that’s not what I’d call elegant. So I am considering to somehow build the thing on a plastic basis. Cast it, mill it with a cnc-mill, whatever…
Anyway, I will leave this problem be for now and rather start working with the existing model. That means:
– get an Arduino
– connect it to the existing circuit and PD
– put it all into the ball and check out what it can do

All that in probably two weeks, because now I need a vacation from it all.

A New Gadget

Wednesday, August 4th, 2010

Living in Berlin forces me to do quite a lot of cycling every day. These extensive trips tend to be quite boring when they repeat themselves and music helps passing the time. My style of driving allows no earplugs and since the shipment of speakers for the Diskokugel arrived, I came up with my own bike sound system.
It’s made up out of standard sewage parts (fire proof, for what its worth) and hold a tda7052 as amplifier. I’m thinking about making a series to sell them, but for now the cost of the parts add up to € 12,- and it takes some time to build them. Seems, electronic devices are only cost-efficient when assembled by children in asia :-(

The raw parts

The raw parts

Biker Sound SystemBiker Sound System

The TDA7052 runs on 4 AAA batteries and lies on the bottom of the tube. There is also the on/off switch. The whole system is (hopefully) waterproof.

The TDA7052 runs on 4 AAA batteries and lies on the bottom of the tube. There is also the on/off switch. The whole system is (hopefully) waterproof.