at second glance

guerilla messaging device

"media extensions" semester project at UdK Berlin, 2006/2007

A multi-purpose guerilla messaging device, made to place hidden critical messages within the abundant medial environment in the city.

development blog entries


the original idea was to build self-powered christmas tree balls with a chain of LEDs underneath enabling them to display hidden typography and symbols using the „persistence of vision“-effect which become visible only in case of eye movement or long-exposure shots with cameras.

soon the true potential became obvious; a neutrally-shaped device with the ability to display images can be used everywhere in public space, where the eyes follow movements or objects are moving through the field of vision.

application scenarios

the conceptually most interesting application is the stationary use of the object when it is displaying content that is critcising other messages in tits surroundings.

for example, placed on an ad for a supplier of cheap nuclear electricity, the device can show a radioactivity symbol.

in order to see the symbol, people have tho shake their heads in front of the ad, so they are performing a gesture of negation. this way, the observer is included in the setup and completes the statement by trying to see the content displayed...

the initial spark for doing so is the subconscious movement of the human eye, called "saccade" which reveals the content very short but noticeable somewhere in the observer's field of vision.

another scenario would be to place the device near a race track, where people follow the cars with their eyes or even a camera. criticising the enormous amount of emissions produced, the writing "CO2" is displayed.

as a subtle warning sign for speeding drivers, the device is placed next to a highway showing crosses. if one passes by fast enough, he will see them and is reminded of the risky nature of his current activity

(in the last two cases, typography can be used, since the direction of movement is known. in the headshaking scenario, the use of symmetric symbols is imperative, since on changing the direction of eye movement, the content is flipped horizontally)

the prototype

the prototype consists of 32 ultrabright LEDs in an aluminium casing controlled by an Arduino NG board and 8 shift registers, so that on the one hand only 3 output pins are needed, and on the other hand the length of the display can be easily extended by 8 LEDs per shift register. this way, even 64 or 128 LEDs can be used.

the LEDs are placed below a piece of milky white plexi glass serving as a diffuser, so the viewing angle is increased. square holes give the image a pixelated look.

long exposure shot taken while panning the camera

the image is stored in an array of long integers, the single bits are used to determine if a LED is on or off. an image (gif) of 32*32 pixels dimension can be loaded into a processing sketch which generates the numbers, that can then be copied into the arduino program and uploaded to the board.

download processing and arduino source code