FR2502823A1 - Laser control arrangement for musical synthesiser - uses mirrors to reflect laser beams to photocells in synthesiser control circuits for control by beam interruption - Google Patents

Abstract

The light beam (A) from a laser is split into several beams (D) by a separator (B). These beams are reflected by mirrors (C) to pass to photocells (E) located at various parts of a stage so that they can be interrupted by various parts of a performer's body. The photocell outputs are connected to a system which produces different voltage levels. These different voltages control a voltage controlled synthesiser to produce the corresponding musical sounds in frequency, amplitude or tone as previously determined. The photocell outputs may also control lighting simultaneously with the sound.

Description

 The present invention relates to a control system for musical or similar synthesizers by laser beams.

 Electronic musical instruments of the synthesizer type are sets of sound frequency generators provided with a certain number of auxiliary circuits allowing variations in timbre, amplitude and frequency. In analog-type synthesizers, the base frequency can be modified by injecting a control voltage into the oscillators.

 The voltages used to control the variations in frequency of the oscillators are generally provided by a piano-type keyboard as to its mechanical aspect. The keyboard of a conventional apparatus can cover a sound range of two to ten octaves and its limitation is a limitation of a physical order, since its maximum length generally corresponds to the extent of the arms spread apart by the interpreter. The traditional method of playing this type of keyboard involves the use of the fingers of the hand.

 The present invention aims to overcome the limitations of the traditional keyboard and to make possible a musical game using different parts of the body, mainly; fingers, hands, arms, and even the whole body.

 To achieve this result, the keyboard keys are replaced by a certain number of rays from a laser.

 The laser has among other peculiarities, that of providing a ray which, in the visible wavelengths, has the property of very little divergence. This ray when it is of sufficient power, and placed in the presence of particles suspended in the air, such as dust or smoke, becomes very bright and visible even in very strong ambient light.

 The invention therefore uses this property to replace the keyboard keys with visible light rays.

 The rays of the laser are directed towards photoelectric cells which, reacting according to presence or absence of light, modify the state of electronic circuits which then produce potential differences being used to control the frequency of oscillators, or the timbre of filters, or the amplitude of amplifiers, since these three elements in a synthesizer are controllable by voltage.

 The performer can then close off the different rays that he calls with different parts of his body to produce the different musical events.

In one of its most important applications, the control system according to the invention is presented as a frame of triangular, or circular, or square, etc. shape, which includes at one place the arrival of the laser beam with a system making it possible to divide this ray into an indefinite number of rays, this using for example dividing blades or else lined networks. These rays, after having traveled a path either direct or complex, come to strike photoelectric cells placed in different places of the frame.

 The performer will then be forced to use for musical creation only the parts of the body that are easily accessible depending on the shape or size of the frame.

 In another application, the rays, after a more or more complex course of care, always end up on cells, but this time their course is not limited by a frame, but by the mimic dimensions of the place where the system is installed, the or the performers, as they can then be among several, may, while evolving in this space, cause the emission or modification of the sounds.

 Of course, each photoelectric cell being able to be linked to several electronic control systems, it will then be possible to simultaneously control sounds and lighting of the traditional type.

 The accompanying drawings provide a better understanding of the physical principles of the invention and show two exemplary embodiments.

 Figure 1 is a schematic representation of an example of a frame that can be used by a single interpreter due to its proportions.

 Figure 2 is a schematic representation of a more spatial installation where several performers can evolve by modifying the sound structures.

 FIG. 3 is a general diagram of optical and electronic operation of the invention.

In FIG. 1, A represents the frame supporting all the optical parts, B the incoming laser beam, C the ray separator system,
D separate rays, E cells.

 In Figure 2, A represents the arrival radius, B the separating system, C the ray return mirrors, D the various rays, E the cells.

 In figure 3, A represents the laser, B the ray coming from the laser, C the separating system, D the rays, E the photoelectric cells, F the electrical connections, G the circuit which provides the potential differences to the synthesizer, H the voltage controllable synthesizer.

 The invention by its principle of spatialization of musical control, allows to expand the field of creativity, especially in terms of concerts and dance by creating a spectacular audio-visual relationship.

Claims (4)

 1. Musical synthesizer control system characterized by the fact that sound control is established by the presence or absence of laser rays on photoelectric cells.  2. Control system according to claim 1, characterized in that the obturation of the rays can be produced by any part of the human body.  3. Control system according to claim 1, characterized in that the obturation of the rays can be produced by any physical element in mDwement.  4. Control system according to claims 1 to 3, characterized in that the information coming from the cells simultaneously confined sound and light.