Art can be called interactive if an intelligent response (in terms of changing lights, sounds, images, moving objects etc.) to an action by a performer or visitor or to a changing environment occurs. To add such interactive capabilities to their art or performances artists have to engage in a costly and difficult dialogue with highly skilled technical persons. A data acquisition and processing system based on MIDI and Opcode’s Max is proposed to facilitate, for artists, the design and creation of interactive art.
Many artists include some form of interaction in their creation (Atkins (1994). Crawford (1994), Demers (1993), Schiphorst (1992). Malina in Leopoldseder (1990)). An interactive art installation may have a response to an action of a visitor, or in a performance, the artist may control or interact with one or more media. To detect the actions of the visitor or performer sensing devices are required. In addition to this, it may be of interest to capture environmental variables, such as room temperature or windspeed. Up to now artists had to fall back on existing, commercially available controllers or sensing devices, designed for specific applications, i.e. with little flexibility, to include such interaction. Before examining existing sensing devices, it is important to distinguish the levels of abstraction that can be used in describing events and changes in the environment and human behaviour. For example, the description of an event or change can be:
- physical (lightlevel in lux is represented in voltage)
- signal (rate of increase of light level)
- gestural or environmental (hand moves away from light sensor, or lights are coming up)
- emotional or multimedia (tension increases in the currently playing sequence of sounds, lights. images etc.)
These distinctions are important because the aim is to interpret the events or changes in a given context so that they can be used to generate other events or changes. Therefore they need to be expressed in a similar representation as that of the context. This can be achieved by analysing the events and extracting features, information, meaning etc.. For instance, if the system would describe touch as the amount of pressure exerted on a surface by a finger it is not apparent from the data, without further analysis, that someone is hitting the surface or stroking it. Transducers describe an event or change only at one level of abstraction, ie. in physical terms. They are devices that generate an electrical signal (voltage, current, charge, ..) as a result of an event. Sensors and detectors however address a variety of levels of abstraction. Sensors, transducers and detectors are all sensing devices. These distinctions are also very useful in the dialogue between artists and technologists, since they often communicate at different levels of abstraction.
- Axel Mulder (Netherlands) is a musician who designs interactive art systems. He is writing a doctoral thesis on gestural control at the School of Kinesiology of Simon Fraser University, B.C. and is a member of the review board of Leonardo. He has researched the field of neuro-motor systems, written a science research project to develop a sensor for the measurement of flexion and extension of hand joints, and developed a piezo-electric sensor for a hand gesture interface.
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