KYLE E. EVANS
Kyle Evans

de/Rastra

Image by Duran Blakeley


The de/Rastra oscillographic synthesizer is a real-time audio/video instrument and computer-interfacing device that allows a performer to generate visualizations intrinsic to cathode ray tube technology while simultaneously creating the acoustic analog of the displayed imagery. By way of building, bending and mutilating, de/Rastra shows the effects of altering the anatomical makeup of a CRT television, revealing the hidden potentials of the technology through the repurposing and restructuring of its own ability. Through hacking and exploiting the capabilities intrinsic to all CRT devices, the technology becomes repurposed as a performative interface, breaking down the device’s ‘consumption only’ nature. The performer is given control over the technology by removing it from the intended application and forcing it into an active state through a combination of physical and mental effort.

The de/Rastra oscillographic synthesizer is an open source project. An oscillographic TV hacking tutorial can be found at: http://yaktronix.com/osctv and related tutorials can be found at: http://www.crackedraytube.com/textstutorials.html

 

- Video

 

 

- de/Rastra Full Text

 

 

Technical details:

-Oscillographic TV Hacking Tutorial-

-Electromagnet TV Hacking Info-

-Original Concept Sketch-

-System Schematic-

-Max/MSP Patch Download-

Computer interfacing:
-Atmel 328 communicates with a program designed in Max/MSP via xBee wireless communication.

-4 Force sensing resistors: generate sounds and visuals by varying the amount of pressure applied to them.

-3 axis accelerometer: modulates signals as the instrument is moved through space.

-4 momentary push button switches: Generates sonic and visual accents and quick events.

-6 flip switches: Used to change between the different program states throughout the performance.

Visualizations:
Multiple audio signals created by the Max/MSP patch are amplified by a 4 channel power amplifier @ 100W per channel and inserted into the CRT's yoke (X and Y deflection axes controlled by different signals). This deflects the electron beam in a fashion that is directly connected to the audio being produced.
Additionally, an electromagnet inside the CRT, also being driven by an audible sine wave, deflects the beam further creating the colorization.

Image by Marco Donnarumma