Monday, September 27, 2010


Teufelsberg was an NSA listening post during the Cold War in Germany. US agents listened to radio transmissions from the GDR. The site has an interesting history. Under the 400,000 buildings worth of rubble that the tower sits on is a Nazi Military Technical College designed by Albert Speer.

The site is abandoned now, but is sometimes used by artists because of its acoustics (the main tower has a fully enclosed geodesic sphere), surfaces which are conducive to projection, and historical significance.
Copyright Spreephoto, see more images here:
Video artists using Teufelsberg as a projection screen

Sound artists using Teufelsberg as a studio

Some amazing photos:

Info on the Military Technical College:

Good blog on ruin, ruin value, and Teufelsberg:

More Links!

this time to build your own shortwave radio transmitter. schematics look intimidating, but hopefully do-able!!

Convert AM Radio to Shortwave

An instructables link to instructions on how to listen to shortwave radio broadcasts on an am radio.

Berlin Radio International

BRI was the 'voice' of the GDR (East Germany) before unification in 1990. It was broadcasted over shortwave radio and the station was terminated when Germany unified.

Here is a link to their final broadcast.

Tuesday, September 21, 2010

Sensor Research #2

more on piezos

from Sensor Wiki


Piezoelectric sensing of acceleration is natural, as acceleration is directly proportional to force. When certain types of crystal are compressed, charges of opposite polarity accumulate on opposite sides of the crystal. This is known as the piezoelectric effect. In a piezoelectric accelerometer, charge accumulates on the crystal and is translated and amplified into either an output current or voltage.
Piezoelectric accelerometers only respond to AC phenomenon such as vibration or shock. They have a wide dynamic range, but can be expensive depending on their quality (Doscher 2005)
Piezo-film based accelerometers are best used to measure AC phenomenon such as vibration or shock, rather than DC phenomenon such as the acceleration of gravity. They are inexpensive, and respond to other phenomenon such as temperature, sound, and pressure (Doscher 2005)

Monday, September 20, 2010

blah blah theoretical blah blah blah

Frederick Kiesler and Marcel Duchamp

Kiesler (1890-1965) was an architect, artist and theatre designer. He believed that 'art had the ability to balance' (or modulate) 'the technological, natural and human environments.' That 'art' (or architecture) 'could point out current imbalances and suggest solutions' to these imbalances. He was intrigued by the window and used its qualities in his design of sets, architecture and storefront windows. 

Kielser's Triptych

'The storefront window is a silent loudspeaker.'

Kiesler saw 'reflective glass as a catalyst for a relationship between viewer and object.' That this 'borderless space' could 'dissolve the barrier and artificial duality of vision, reality, image and environment.' The properties of reflective glass give 'an illusion of a three dimensional world on a two dimensional plane' and implicate the viewer directly into the scene behind the glass. Glass, as both 'a surface and a space' is an enclosure that divides and links at the same time. This 'gateway' relies on the presence of the viewer. 

Marcel Duchamp shared similar beliefs on the properties of glass as he worked with the material in many of his pieces. The Large Glass, a large painting / sculpture, is built onto glass and is often photographed with the space behind the work showing through. Duchamp thought in analogues. Projecting the third dimension onto a two dimensional surface was likened to a four dimensional object being projected onto a three dimensional object. 

 Bride Stripped bare by her Bachelors, Even or The Large Glass, 1915-23

The content of The Large Glass deals with four dimensional geometries, mechanomorphic beings and sexual and translational overtones. 

In a similar vein, I propose (very early, very rough proposition) two similar machines, to be mounted on opposite sides of a window pane. Using temperature as a generator of electricity, one machine will produce vibrations, the other will translate those vibrations to sound. This configuration implicates the viewer, speaks to the collapse of space (via temperature) onto a two dimensional pane and also uses the thickness of this two dimensional plane as a transmitting medium. Because these machines use temperature difference as a generating force, it also calls to imbalances in the environment.

All text in quotations is from


Saturday, September 18, 2010

Immaterial - Material

Selections from the exhibition The Quick and The Dead, which I saw last year in Minneapolis.

Eleey, Peter. The Quick and the Dead. Minneapolis: Walker Art Center, 2009. Print.

Sabrina Raaf

"...During the series of Saturdays, I also recorded the sounds of my neighborhood – the women singing out their windows to their radios, the young men in their low rider cars circling the block, the children, the ice cream carts, etc. These are the sounds that are mixed in the piece. And, these are the sounds that literally drip from participant’s fingertips in Saturday. 
Saturday is presented in the form of an interactive glove. In order to hear the audio, participants magically just press their fingertips to their forehead and they hear the sound without the use of their ears. The glove is outfitted with leading edge audio electronic devices called “bone transducers” which make this possible. These transducers transmit sound in a very unusual fashion. They translate sound into vibration patterns which resonate through bone." - Sabrina Raaf

"... It hugs the room’s walls and responds to the carbon dioxide levels in the air by actually drawing varying heights of ‘grass’ on the walls in green ink. The Grower robot senses the carbon dioxide (CO2) level in the air via a small digital CO2 sensor. This sensor is mounted high on a wall of the exhibition space and sends data wirelessly to the robot. The number of people in an exhibit space breathing in oxygen and exhaling CO2 has an immediate effect on the sensor. My robot takes a reading of the CO2 level every few seconds and in response it draws a vertical line in green ink on the wall." - Sabrina Raaf

Thursday, September 16, 2010

Sensor Research

From Sensor Wiki:

Temperature-transducer ICs

Semiconductor temperature sensors are produced in the form of ICs. Their design results from the fact that semiconductor diodes have temperature-sensitive voltage vs. current characteristics. When two identical transistors are operated at a constant ratio of collector current densities, the difference in base-emitter voltages is directly proportional to the absolute temperature.
The use of IC temperature sensors is limited to applications where the temperature is within a –55° to 150°C range. The measurement range of IC temperature sensors may be small compared to that of thermocouples and RTDs, but they have several advantages: they are small, accurate, and inexpensive.
Temperature sensing ICs are available either in analog form, which output a voltage or current which is proportional to the temperature, or digital, which communicate temperature over a digital communication line, such as one-wire PWM, two-wire I2C, or a multiple wire SPI connection.

Piezoelectric Sensors

Piezo sensors are used to convert mechanical movements, such as force, vibration, acceleration or pressure, into electric signals. Piezoelectric elements are widely used in a variety of sensors such as accelerometers, contact mics, and ultrasound transducers. Piezoelectric sensors can be used as force-sensitive switches, threshold detectors, analog pressure sensors, and acoustic vibration pickup.

Piezoelectric ceramic elements are also found in watches, alarm clocks, old portable video games, and many other commercial products which contain sound generating devices. Piezo-buzzers typically operate at their resonant frequency with various construction options. Since in many cases piezo sensors are simply reversed buzzers and actuators, these sensors exhibit a resonant frequency that they are more sensitive to. These inexpensive transducers can be salvaged from old products or obtained from the usual sources (i.e. digikey, etc.) with specific electrical properties (operating voltage range, sensitivity, capacitance, resonant frequency, etc.) for optimal operation.

1st Day Data Collection

taking the temperatures of windows on campus

Data Recorded:
Interior Air Temperature
Interior Pane Temperature
Window Thickness
Exterior Pane Temperature
Exterior Air Temperature

Two-paned windows had an average temperature difference of 5.4C (on either side), while one-paned windows had an average difference of .4C. The difference between the air temperature inside and the temperature of the interior window pane was 2.6C, for two-paned windows, and 5.8C for one paned.