Artists who create interactive systems and artistic interface designs have begun to look for new display possibilities. For this reason façade’s of contemporary buildings have been largely investigated as a sort of membrane for the display of interactive digital content. These facades often make use of intrusive systems such as LED displays, monitor walls, or light bulb systems that fully cover the buildings to achieve large scale image displays. While LEDs are very expensive, monitor walls hardly work at daylight situations, and light bulb systems have only limited display capabilities. Equally we may understand that the mode of apprehension of media facades has changed tremendously compared to traditional types of building surfaces.
As a team of two media artists (Laurent Mignonneau and Christa Sommerer) and an architect (Michael Shamiyeh) we investigated the potential of modern media facades as membranes. In 2008 we developed and patented a system called Solar Display, which provides a novel, modular, self-powered, environmentally friendly, and non-intrusive display possibility for media content on large facades. Solar Display is currently being installed at the University of Art and Industrial Design façade at the main square of Linz, Austria.
The core element of the system is a grid of self-powered solar pixels. Each solar pixel unit consists of a movable element, that is covered with solar cells. All Solar Pixels are mounted on a flexible grid. The amount of Solar Pixels, their size and their fixation pattern on the grid is modular, depending on the overall size of the media façade and the over-all image resolution that should be achieved. The smaller the Solar Pixels and the larger the overall surface, the finer the resolution of the whole display can be. The overall image effect is achieved when the various Solar Pixels are variably inclined, seen from far this creates different levels of grayscales, as each Solar Pixel can represent levels of white to dark depending on its inclination angle.
One of the most challenging part of designing an outdoor display is to produce an image that will go against the sunlight. Facades are usually exposed to the sun to take advantage of the heat it produces. The conventional light driven displays are usually consuming a lot of electricity to produce good brightness and contrast that can compete with the sun’s brightness, and by doing so they also produce a large amount of wasted heat and electricity. Compared to LED displays and monitor based systems our Solar Display provides an alternative by using the sunlight instead of working against it. Solar energy is harvested by each Solar Pixel to power the electronic circuits, the motor and the communication unit in an efficient way and by storing some extra energy for times when sunlight is not available. Sunlight is also used for controlling each Solar Pixel’s brightness shading depending on its orientation angle and inclination. This allows us to run the display in full daylight and direct sunlight conditions.
All Solar Pixel units communicate between each other via embedded infrared communication units. The Solar Display itself consists of a sufficient amount of Solar Pixel units, which, seen from far, create an overall image that can display simple texts or images, advertisements, announcement or more artistic media content. Solar Pixel oriented towards the ground appear darker while oriented towards the sky they appear lighter. A central computer manages the incoming data, coming either from the local hard drives, cell phones, cameras, SMS, or from the Internet. All these data can be processed by our system and sent as inclination instructions to each single Solar Pixel. The overall effect, when seen from a distance, is a whole image, a text or a moving animation or interactive content on the Solar Display façade.
In addition to its display function our Solar Display, can also work as a shading system. As each Solar Pixel unit can be controlled individually and centrally, they can for example be oriented in such a way as to only block out light at the areas needed. Window areas can for example be covered and closed to block out light while the rest of the façade can be revealed or opposite, windows can be revealed at the rest of the façade can be covered. In this way our Solar Display façade is adaptable to the various needs such as display functions as well as shading functions.
In Linz historical buildings façades at the main square are protected under the law of historical monuments. There is a long historical discourse of the function of building facades. Our approach is one of protection of cultural identity and sensibility towards cultural heritage. Our Solar Display system was conceived as to not destroy or fully obstruct the neo-classical façade behind; rather, each Solar Pixel unit leaves a certain amount of the original façade being seen, depending on the Solar Pixel’s inclination. For example, when all the pixels are being oriented towards the sky, the original façade is entirely visible. To not destroy the neo-classical façade, a light weight frame was designed to function like a curtain that can be installed easily and can be adapted to the surface and purpose needed. As each Solar Pixel is independent, the Solar Display can be easily extended to very large surfaces without the use of extra cables and heavy mounting casings.
In the images, from top to bottom:
The Solar Display featuring text. The system is being installed at the University of Art and Industrial Design façade in Linz Austria in 2009.
The Solar Display used in the layering function. The original neo-classical façade is still visible while only parts of the façade are being used for display functions.
The Solar Pixel unit.
The movable Solar Pixel unit at two levels of inclination.