the loud objects

Marius Watz made a nice video documentation of the loud objects performance he attended at monkeytown.

It is a live physical computing concert, where they hook up different sound components on a overhead projector making it interesting also visually.


Backjumps – the Live Issue #3

Backjumps – the Live Issue #3 03, originally uploaded by hc gilje.

I was back in Berlin for a week in beginning of july, and got the chance to see the excellent exhibition BackJumps -the Live issue #3, which cover new and recent street art works in Germany and the rest of the world. It was partly a exhibition using the huge space at Kunstraum Bethanien, and partly documentation of work from urban spaces. I saw many interesting projects, but will mention two which relates directly to this project blog:
The first one is a animation shown on a monitor in a small room (see image). What´s interesting is that the animation was made on the walls in the same space and you see the trails of the animation on the walls. It is made by Bologna based Blu.
The other project was part of CubaBrasil, Los Berlin BeamBoys, which did huge video projections on buildings in Cuba, partly as a way of bypassing the censorship of certain political slogans and images.

Another useful link, reclaim your city .

I also picked up an interesting book at DAZ, Urban Pioneers: Temporary Use and Urban Development in Berlin. It just came out, but already some of the locations covered in the book have disappeared and been replaced by new buildings.

directional sound

May I Have Your attention, Please, originally uploaded by

I am doing a series of projects called soundpockets for urban interface oslo, which in different ways tries to create pockets of sound in public space. Some of the versions involve the fm sender- mp3 setup mentioned in the previous post, another one involves a directional speaker mounted on a pan/tilt unit, and this has been my second headache this summer, finding a controllable pan/tilt unit which is reasonably fast, which can handle a load of a few kilos and which is not ridiculously expensive.

Fortunately I have had good help from Soundscape studios. The first ideas was to use a existing movinghead light and refit it with the speaker, but it turned out that the motors wouldnt be able to handle the load. Pan tilt units are usually made for a specific purpose, either light or video, and the few ones which are available for general purpose use and which are controllable are very expensive.
The one we have ended up with is quite expensive, but is controlled using serial protocol, is made for outdoor use, and is powerful enough to handle video projectors (for later projects). It is also very fast, up to 300 degrees per second pan, and 60 degrees per second tilt. Hopefully it arrives next week.

The most ambitious plan is to control it using an arduino microcontroller, which will also control a serial-controllable mp3 player, the daisy, so I should be able to place sounds quite accurately in a space, and also create movements with sounds.
If time runs short I will use a macmini with max controlling the sound and pan-tilt unit over the serial port.

I have been testing two different models of directional speakers which uses ultrasound as the carrier signal, I will probably have to go for the smaller one, although I am a bit worried it will disappear in the ambient sound. It is also challenging to find the sounds which works best, and also how to deal with the sounds both coming directly from the narrow beam of the speaker but also the reflections on surfaces in the space.

The inspiration for this projects comes from when I studied in Trondheim in the 90ies, and I heard some stories about how a directional speaker had been used to cause a certain distress on a bridge over the local river: A person walking alone across the bridge suddenly hearing whispering voices. An out of tune clarinet projected into a marching band playing on the 17th of may (Norway´s national holiday).
If these stories are true or not, doesn´t really matter, it is the idea of having a private experience in a public space which intrigued me.

solar energy + fm sender + mp3 = #$!#%!

solar charger posing at helgøya, originally uploaded by hc gilje.

Summer has seen few posts, but not because of lack of activity. I have been busy researching for the upcoming urban interface oslo exhibition. One of my challenges has been to find a setup with a short-range fm sender, a mp3 player and a solarcell/battery solution that would make it possible to place this unit anywhere and leave it running. This has proven a lot harder than I would have imagined.
First, there are now so many fm senders available, and it is really hard to distinguish good from bad (90 % bad), and the reviews out there are not trustworthy. There also seems to be so many factors affecting signal strength so the same sender might appear to have a strong signal one day and a really weak one the next day. Frustrating and time consuming, and I am still checking out different modules.

I guess I should ask Raghav Mahato in India, who claims to have built a radio sender for just over 1 usd.

I knew very little about solar power solutions before this summer, and the options range from build it yourself solutions to “how to survive after a nuclear attack” systems. I looked first at relatively new products advertised as solar chargers for mobile devices like ipods, cellphones and pdas.
Most of these mobile solar chargers combines small solar panels with an internal rechargeble battery with different types of breakout plugs.
Not all of them are able to provide power while charging, which was necessary for my setup. I gave the freeloader a try as it sounded like the perfect companion for a fm sender and mp3 player, it has a 2100 mAh battery, but the results were very disappointing. I guess the current from the solar panels is just too weak to provide enough power to keep the battery charged while in use.
There are not so many other ready-made solutions, either they have a smaller capacity than the freeloader or they are just chargers (so the batteries can´t be used while they are being charged).
I am now looking at more heavy-duty solutions, 6-15W solar panels in combination with a charge controller and a lead battery, but this becomes quite expensive and heavy. And all I need is about 100-150mAh. I am still hoping for the perfect solution to pop up.

This research  will also be useful when looking for selfpowered xbee solutions. They seem to have had success with a solar powered xbee system at ITP.
I managed to do a little bit of work with the Xbees a few weeks ago, finally getting the directmode (connect a input of one xbee to the output of another xbee, without using an external microcontroller) to work, and also exploring the sleep options, which means being able to keep the power used to a minimum.

I have discovered lots of interesting alternative energy websites, here are a few of them:

otherpower, gotwind, cirkits links, altenergystore