Electronic assembly for the production of wireless string instruments

An optoelectronic pickup that generates a fluctuating voltage that is analogous to the vibrations of a vibrating body. When utilized with the vibrating body of a musical instrument and amplified and fed to a speaker the musical tones are reproduced at an amplified level. When the signal is fed to an FM transmitter the musical tones can be reproduced in any FM radio receiver. The device makes possible portable electric instruments and ‘wireless’-electrical instruments, i.e. a guitar that does not require a connecting cord or amplifier. The device anticipates new and unique musical instruments.

BACKGROUND OF THE INVENTION

The present invention relates to an optoelectric pickup unit that is responsive to that part of a musical instrument that vibrates when the instrument is played.

The standard magnetic pickup has a weak signal and can only be utilized with metal strings, is sensitive to stray fluctuating magnetic fields and has limited frequency response.

U.S. Pat. No. 3,733,953 issued to Mr. Ferber in 1973 discloses an optoelectric pickup that operates on the principal of a string intersecting the path of a light beam from a light-emitting device toward a light-detecting device. Mr. Ferbers' invention has some of the same advantages as the present invention but must still have a complicated sound box with an acoustic speaker, which makes for a large and heavy instrument that is technically difficult to manufacture.

U.S. Pat. No. 05,012,086 issued to Mr. Bernard in 1991 claims to overcome several of the disadvantages of previous optoelectrical pickups but is itself of such a highly technical nature as to be difficult to understand or reproduce.

Pizeo-electric transducer pickups have been devised that overcome some of the deficiencies of the magnetic pickup but these, like most others, require an electrical connection cord and a separate amplifying system.

OBJECTS OF THE INVENTION

It is an object of the present invention to provide a light-weight pickup that facilitates the production of portable electric musical instruments that have a self-contained amplifying unit.

It is another object of this invention to provide for the production of ‘wireless’ musical instruments, musical instruments that are as portable as their acoustic counterparts by utilizing a radio transmitter to broadcast their musical vibrations to any nearby radio receiver, eliminating the necessity for a connecting electrical cord and amplifier.

It is another object of the present invention to provide a simple pickup that is easily manufactured providing lightweight low cost electric musical instruments of good quality to the general public.

DESCRIPTION OF A SIMPLE EMBODIMENT

FIG. 1shows a perspective view of a soundboard32from which an ambient light shield34is removably attached by means of screws. String supports40and41have a string42tensioned in between. A light-emitting source38is soldered to a printed circuit board43facing a light-detecting element36, which is also soldered to the printed circuit board43. The string42is mounted so that the light from38is interfered with before it impinges on light detecting element36. When36and38are suitably biased by a battery (not shown) and the string42is set into motion, the light impinging on the photo-detector is interfered with causing a fluctuation in the current through the detector36, and causing a fluctuating voltage at the junction of the detectors' emitter connection and resistor R2ofFIG. 2, that is analogous to the frequency of vibration of the string.

DESCRIPTION OF A PRACTICAL EMBODIMENT

FIG. 3is a perspective view of a one string bass electric instrument showing a tubular ambient light shield34with a string42tensioned through it and attached inside the enclosure30to ambient light shield support41on one end and tied to an adjustable tensioning device18on the other end.

FIG. 4is a view along lines4—4which shows the string42, tensioned in between a light emitting source38and a light detector36in such a way as to interfere with the light from the source impinging on the light detector.

The basic musical tone of the string can be raised or lowered by the adjustable tensioning device18.

The instrument is played by holding down the string42on the fingerboard20and plucking the string near the ambient light shield in a direction normal to the fingerboard.

Referring to FIG.5—once the string has been set into motion the light from the light emitting diode1is interfered with before it impinges on light detector1causing a fluctuating current in light detector1, which causes a fluctuating voltage at the junction of the emitter of light detector1and resistor R2. The electronic signal thus generated is fed through potentiometer1to an audio amplifier and then fed through potentiometer2to the gate of Q1regulating the current through the dynamic speaker in such a way as to reproduce the musical tone of the vibrating string in an amplified form. The volume is controlled by adjusting potentiometer3, which also contains on/off switch S1.

DESCRIPTION OF A PREFERRED EMBODIMENT

FIG. 7is a perspective view of a ‘wireless’ electric guitar with the ambient light shield34removed showing a conventional guitar head24and neck22attached to a soundboard32and enclosure30with a bridge26attached that provides for securing one end of 6 guitar strings.

FIG. 8is a view along lines8—8which shows 6 guitar strings tensioned between 6 pairs of optoelectric pickups comprised of light emitting diodes and light detectors. The light emitting diodes and light-detectors are soldered to printed circuit boards and bent at 90° angle. They can be adjusted by further bending of the leads to cause a maximum electrical signal in the light detectors output.

FIG. 9is a view taken along line9—9ofFIG. 8showing a single guitar string42in relation to light emitting diode38and a light detector36.

Referring toFIG. 10there is a battery with an on/off switch S1which when in the on position provides power for the circuitry. The light emitting diodes are connected in parallel with each other and bussed to a common current limiting resistor R1to ground.

The light detectors are connected in parallel and bussed through R2to ground. The output voltage from the junction of the light detectors emitters and R2is fed into the input of an FM transmitter where the signal is amplified and broadcast through space by a 7 inch piece of wire that acts as an antenna. The transmitter has an effective range of 50–75 ft. With the values shown it can be tuned to a frequency of around 100 MHz. The musical tones of any and all strings being played can be reproduced by any FM radio.