It is well known that before starting playing guitar or any similar instrument, a musician must adjust the tension of the strings so as to obtain a perfect acoustic correspondence to his musical desires.

It is also well known that also during a performance, often the perfect tuning gets lost which would require a new tuning that is not allowed by the continuity of the performance itself, and this implies inaccuracies in said performance.

It is the aim of the present invention to make the tuning process for guitars and similar instruments automatic and independent, before and during each performance.

The aim set forth is reached by means of the electronic device according to the present invention, comprising a plurality of sensors placed on the strings of the instruments and that take their elastic vibrations ; a control unit for determining the features of the notes played, according to the vibrations coming from the strings of the instrument, comparing the same with the optimal features of standard notes recorded in special memories,

so as to obtain the data requested for the traction to impress to the single strings for obtaining the optimal tuning thereof ; an interface controlled by said control unit, for managing a plurality of servo-mechanisms for the traction of the strings, fed by incorporated electric batteries and housed in special containing structures placed besides the head, and that is able to act onto those pins the strings are linked up with, impressing the strings such a traction as to determine the optimal tuning thereof.

The advantage of the device according to the present invention is evident.

The present invention will be described more in detail herein below relating to the enclosed drawings in which some embodiments thereof are shown.

Figure 1 shows an axonometric view of an electronic automatic tuning device according to the present invention, applied to a guitar C.

Figures 2 and 3 particularly show the location of the constitutive elements of the integrated device in a guitar C, while figure 4 shows a block scheme of the functioning of the same.

Figure 5 shows a variant of the device according to the present invention that may be applied as an optional fitting to music instruments that are not provided with any possibility of automatic tuning, while figure 6 shows a possible application to a conventional guitar C'.

Figure 7 shows a variant of the device according to the present invention that may be used by means of a personal computer provided with a special expansion card for managing the functioning thereof.

Figure 8 shows, in a block scheme, the working principle of the device according to the present invention, while figure 9 shows a possible application to a conventional guitar C', being in interface connection with a managing personal computer PC.

The enclosed figures show an electronic device for the automatic and independent tuning of guitars and other stringed instruments, that may be integrated during realization in said instruments or applied to the same as an optional fitting, consisting of : a plurality of sensors 1 placed on the tailpiece CO in correspondence with the strings CR of a guitar C, for taking the entity of their elastic vibrations; - a control unit 2 for determining the features of the played notes on the vibrations emitted by the strings of the instruments, comparing them at the same time with the optimal features of standard notes recorded in special memories 3, thus obtaining the data relating to the traction to be impressed to the single strings CR for obtaining the optimal tuning thereof ; - an interface 4 for the control of special servomechanisms 6 for the traction of said strings CR of said guitar C, and that is able to receive the data worked out by above mentioned control unit 2 by means of known wiring inside said guitar C, or by means of special infrared, ultrasound, radio waves or other transmitters 5;

a plurality of servomechanisms 6, housed in special containing structures 7 placed besides the head CV of said guitar C, and that are able to act onto pins PN to which said strings CR are linked up with, for impressing them such a traction as to determine the optimal tuning; - incorporated batteries B-B1 with electric feeding.

For what concerns the working of the device according to the present invention, during the regular use the vibrations of said strings CR of guitar C are taken by sensors 1, placed on said tailpiece in correspondence with said strings, and are sent to said control unit 2 for determining the features of the notes played by the single cords of the instruments, comparing the same with the optimal features of standard notes contained in special memories 3, so as to quantify the entity of the traction to be impressed to said strings CR for obtaining an optimal tuning.

The tuning of the instrument on different tonalities is made possible by a special selector 8 that leads the comparison process managed by the control unit 2 towards additional memories 3'containing the features of standard notes of different harmonic scales.

The data taken from control unit 2 are sent to an interface 4 that controls servomechanisms 6, housed in special containing structures 7 placed besides the head CV and that provide for the operating of said pins PN to which said strings CR of said guitar C are linked up with; to said pins a rotation is applied that, in turn, impresses a traction onto said strings CR such as to determine an optimal tuning.

Furthermore, the control unit 2 may be provided with different working possibilities that may be operated by a special control board 9, like precision tuning of each single string or the simultaneous tuning of all of them: this is a function that allows to assure a constant tuning of the instrument, even when the same is in use.

The variant of the device according to the present invention as shown in figures 5 and 6, that may be applied to instruments that are not provided with any automatic tuning function, consists of: - a support 10 that may be applied to the tailpiece CO, having sensors 1 for taking the elastic vibrations of the strings CR of the guitar C' ; - containing structures 11,12 for the housing of the constitutive elements of control unit 2 for the analysis of the tuning status of said guitar C', and for transmitter 5, used for sending the data relating to the optimal tuning of the strings CR of the same to said interface 4 for the control of servomechanisms 6, providing for the traction of said strings, having such shapes 13,14 as to allow the fixing thereof, by means of screwing or gluing, to the outer surface of the sound box CS of said guitar C' ; - a support 15 that may be applied to the head CV, that allows the coupling of said servomechanisms 6, if necessary by means of special converters 16, with said pins PN for the tensioning of said strings CR of said guitar C' ; - batteries B, B1 for opportunely feeding the constitutive elements.

Even with different realization forms, the functioning of this variant is equal to the one of the device described in the previous figures.

Figures 7,8 and 9 show a further variant of the device, according to the present invention, that may be applied to instruments that are not provided with any automatic tuning function, that may be used through a personal computer having a special expansion card for managing the functioning thereof.

Such variant consists of : - a support 10'that may be applied to the tailpiece CO for allowing to put into contact the strings CR of the guitar C'with the sensors 1 for taking the tuning condition of said strings, and having a special interface 17 for sending the acquired data to a personal computer PC to which said interface is linked by means of a special jack 18; - a support 15'that may be applied to the head CV of said guitar C'and that allows the coupling of said servomechanisms 6 to pins PN for tensioning the strings CR of said guitar, having a special interface 19 that allows the control of above mentioned servomechanisms 6 by means of a personal computer PC to which said interface is connected by means of a special jack 18; - feeding batteries B1.

During the normal utilization phase, the vibrations emitted by the strings CR of said guitar C'are acquired by said sensors 1 and sent by said

interface 17, in the most appropriate format, to the personal computer CN, to which said interface is connected through said special jack 18.

Said personal computer has a special expansion card 20 (or a managing software that can perform the same work), that determines the tuning condition of the strings of the instrument according to the data received by said sensors 1 and compares the same with the parameters of equivalent standard notes, so as to exactly determine the entity of the traction to be performed onto said strings CR so as to be considered perfectly tuned.

The worked out data are now sent, through said interface 19, to said servomechanisms 6 that operate said pins PN to which the strings CR of said guitar C'are linked up with, obtaining that said pins are rotated in such a way as to impress to said strings CR the exact traction that determines the optimal tuning.