JPH02154297A - Tuning apparatus for stringed instrument - Google Patents

Abstract

PURPOSE: To allow this device to be used even by a beginner by changing the tension of an relevant string by rotating each of a plurality of bobbin winders, and tuning music notes generated form a string in strumming on the string. CONSTITUTION: A head member 21 is engaged with one bobbin winder 23, and the bobbin winder is rotated clockwise and counterclockwise by a motor 19 in order to pull or loose a string, and music notes generated from the string in strumming on the string are detected, and the basic frequencies of the music notes are calculated. Also, one frequency which is the closet to the basic frequencies is selected from among a plurality of stored prescribed desired frequencies, and the rotation of the motor 19 is driven to a direction changing the basic frequencies of the music notes of the string to one frequency. Thus, a user can easily execute the tuning operation of each bobbin winder while strumming on the relevant string.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application] Although the present invention was originally designed specifically for use in guitars, it may also be used in any other stringed instrument in which the strings are tuned by winding a metal spool. This invention relates to a tuning device for stringed instruments that can be made more easily.

[Conventional technology]

Various proposals have been made regarding devices for tuning guitars. For example, U.S. Pat. A device is disclosed for tensioning and loosening each string of a musical instrument.
This flexible device required a separate equipment e' for each string and has not been able to achieve any significant success on the market.

U.S. Pat. No. 4,018,124 (Rosado) discloses a configuration in which the diodes are turned off when a particular string is tuned, allowing the user to adjust the string tension until the diodes are properly illuminated. However, this device is also unsatisfactory in that it is difficult for beginners to find the desired point tlt and ensure that the string is properly tuned.

Still other arrangements are disclosed in German patent application no. 5509662 and British patent application no. discloses a device that performs all string tuning.

None of these devices have achieved commercial success and require skilled operation or extremely complex and expensive equipment located entirely within the guitar, making them impractical for the average guitar user. Not suitable.

Accordingly, it is an object of the invention to provide an improved guitar tuning device that is convenient for experienced guitar players or that can be used by complete beginners because of its ease of operation.

Therefore, in accordance with the first aspect of the invention, use is made for tuning stringed instruments comprising a plurality of pegs, each of which can be rotated to vary the tension of the associated string and thus the frequency of the notes generated by the string when strummed. An apparatus is provided, the apparatus comprising a hand grippable body and a head member extending outwardly from the body to releasably engage one of the pegs of the musical instrument. The main body is separated from the instrument so that the head member can be moved to engage each peg head independently as necessary, and a motor is placed on the main body to drive the head member. Rotate the above-
the motor rotates two spools, and the motor rotates clockwise and counterclockwise to tension and loosen the strings as necessary;
Sensor means are arranged for detecting notes generated by the strings when strummed and calculating the fundamental frequency of the notes, and means for storing a plurality of predetermined desired frequencies, each associated with each string of the instrument. comparator means for comparing the fundamental frequencies of the notes on the string with all the plurality of predetermined desired frequencies and selecting one frequency closest to the fundamental frequency from the predetermined desired frequencies; Means is provided for driving the rotation of the motor in a direction that changes the fundamental frequency of the base frequency to the two frequencies.

Preferably, the head is moved by the user to select one
It forms part of a manually operable instrument that can be adapted to engage the keys of a guitar. Therefore, the user can tune each peg while strumming the associated string.

Preferably, the device includes switch means whereby the automatic string selection is disabled and the string to be tuned is
! i- Selected and newly applied strings that have not been tuned very properly can be used to tune.

In one configuration, the hand-gripable member containing the head and motor also includes a sensor and comparison system and a power supply battery that provides the necessary power to the motor.

In an alternative configuration, a separate nine box housing contains the sensor, sensor bacteria and necessary switches along with the comparator circuit and is connected to the manual actuator by a suitable plug in the cable. A battery for the motor can be provided in the manual operation section.

Furthermore, in a single configuration, the switch and necessary circuitry may be provided within the guitar itself, and a plug-in may be provided that connects the manual controls to the guitar and allows sequential movement to each spool.

In accordance with a second aspect of the invention, there is provided an apparatus for use in tuning a stringed musical instrument having a plurality of pegs, each of which has an associated string tension, tone quality, and frequency of notes produced by the string when strummed. and a head member extending outwardly from the body and configured to releasably engage one of the spools of the musical instrument. The main body is separated from the instrument so that the head member can be moved to independently engage each peg when necessary, and a motor is mounted within the main body to drive and rotate the head member. The motor is arranged to rotate the two pegs, and the motor rotates clockwise and counterclockwise to tighten or loosen the strings as necessary, and to detect all the notes produced by the strings when strummed. sensor means are arranged for calculating the fundamental frequency of the note on the string, and means are provided for storing a plurality of predetermined desired frequencies, each associated with a string of the instrument; Comparator means are arranged for rotating the motor in a direction that changes the fundamental frequency of the notes of the string to said - two frequencies compared to one of the required frequencies, configured to detect the magnitude of the difference between one of the frequencies and rotate the motor with pulses of different duration;
The magnitude of the difference depends on the duration of each pulse.

Although described above with respect to the guitar, which is currently the most commonly used stringed instrument, the device may be modified somewhat, primarily with respect to the software that generates the desired tones, to adapt the device to other stringed instruments, such as violins, banjos, etc. be able to. Still other devices suitable for tuning pianos can be constructed, but of course this requires storing significantly more frequencies, and typically uses manual actuators to tune a very large number of strings. Select different octaves of the switch to increase.

In addition to various configurations of the device, the control circuitry may be fabricated using any suitable technique. For example, an amplifier,
The device can be fabricated using conventional electronic techniques in which comparators and the like are assembled onto conventional circuit boards. You can also use available tuning boards and different resistors to produce a given tone.
Reliability tends to decline. Additionally, microprocessor control is most preferred as it allows for the widest range of adjustments and changes, including instrument-specific adjustments.

〔Example〕

Referring first to FIG.
It includes a battery section 11 that supplies power to circuitry (not shown) mounted within the interior.The exterior surface of section 12 includes a microphone 13 that picks up all the sound from the guitar and a microphone 13 that is activated to pick up one string of the instrument. A plurality of switches 14 that can be selected and tuned are mounted.Coaxial socket 1
5 is provided on the casing and is connected to a wire 16 connected to the gripping body 1T. The gripping body 1T has a head engine F18' that includes a motor 19 for fully driving a shaft 20 on which a drive head 21 is mounted.

The gripping body 1T has a push button 22 that can be pressed by the user's thumb while gripping the main body and applying the head 21 to the keys 23 of the guitar head 24. In some configurations this can be omitted. A battery section 25 is housed in the base end of the main body.

The head 21 has a groove 27 that passes over the key and is elongated in the direction of receiving a conventionally shaped key, and when the hexagon 2210 rotates, the key moves to # of its axis. ! Crank it to 9 and tighten the string connected to it. Details of the keys are not shown as they are well known to those skilled in the art and will vary depending on the type of instrument involved.

In another configuration shown in Figure 3, the control circuit is mounted within the area of the hand belt tool, and the microphone is also mounted on the hand belt tool and is independent and does not require a nine box. .

Referring now to FIG. 6, the head is shown at 50 and includes a U-shaped opening 51 that can be engaged around the conventional keys of a musical instrument. It is not important that there is a play between the head and the key, since that play is initially picked up by the rotation of the motor and the motor rotates until the key rotates to the Pfr position, regardless of the lost motion between the head and the key. This is to continue to do so. The head protrudes outwardly from one end of the main body 52 and has a shape suitable for being held by the user's hand.
It is placed on 2. A motor 53, a battery section 54, and a circuit board 55 are placed inside the main body.

The battery section 54 can be accessed through an opening at the rear of the casing 52. The circuit board 55 is connected to the display 5 (
l, which can be seen through the opening at the front of the casing. In the front of the casing there is a microphone 57, a socket 58 for the jack plug from the electric pickup, an on/off power switch 59 and each number 60.6.
First and second switches shown at 1 are provided.

In yet another configuration (not shown), the control circuitry and microphone are located within the guitar body, again eliminating the face piece 10. In this case, one multi-position switch can be provided on the guitar to make all the adjustments between the different strings. Socket 1 connected to wire 16 of tool 1T
5 can also be provided on the Yater body. Bacterial power for the control circuit can be supplied from the battery section 25 of the tool, and a separate battery for the motor 19 is provided. Power can be supplied using a DC adapter instead of a battery.

Returning now to FIG. 2, a Zorrock diagram of the circuit of the device is shown.

The circuitry of the device includes a microprocessor at 30 that provides multiple outputs to a two-digit digital display 31.

The input of the microprocessor is supplied by a signal line indicated at 32, which receives the signal to be compared or the note from an input 33 having a microphone 34 and a connector 35 connected directly to the output of the electric pickup of the musical instrument. Filtering circuits are used to remove harmonics and allow the fundamental frequency of the wave to be separated. - The detection signal, which is in the form of a periodic wave with a frequency that depends on the tension and physical properties of the fishing string, is amplified by a first amplifier, indicated at 36. A second amplifier, indicated at 37, over-amplifies the input wave to approximate a square wave having a frequency equal to the frequency of the input wave.

The amplification is performed such that the leading and trailing edges of the square wave are vertical and can be detected by the microprocessor 30.

Another input of the microprocessor is provided by a first switch shown at 38, which can be in the form of a simple push button switch on the outside of the casing which can be manually actuated. A second switch of similar construction is shown at 39.

- A conventional circuit at 40 provides the necessary voltage and timing signals to control the operation of the microprocessor.

The output from the microprocessor is adapted to drive the motor 43 clockwise and counterclockwise, respectively, and the round wire 41
．． 42 will be sent to the top. Therefore, line 41 is connected to transistor 4
A base current of 4.45 mm is supplied and a voltage of one polarity is connected across the motor 43. Similarly, line 42 supplies the base current of transistors 46 and 47 and connects a voltage of opposite polarity across motor 43.

The circuitry and in particular the microprocessor 30 are configured to carry out the following steps.

1. The microprocessor detects the leading or trailing edge of the square wave on line 32 and measures the spacing between successive edges depending on the pulses from the crystal in circuit 40. This period can simply be used to calculate the frequency of the square wave and hence the input wave of notes originating from the string.

2. To improve the accuracy of the calculated frequency, we take the average of waves of 6], for example 5 or 1°, depending on the required accuracy. The average also adjusts for the gradual changes in notes that are changed by the rotation of the motor 43 that drives the associated string key.

6. The noise detected at the input 33 distorts the synchronization of the square wave system (by giving more squiggles depending on the structure of the noise). the microprocessor measures the time difference for a plurality of received square waves and then removes the effects of noise by ignoring or discarding measurement periods that differ from the average synchronization by an amount greater than a predetermined amount; Of course, it is assumed that these differences are due to the presence of noise and unnecessary square waves.

4. As described later, when the circuit is in a specific state for the required instrument, when a tone is detected and the frequency of that tone is calculated, the microprocessor operates and calculates the frequency in the microprocessor. Compare with a set of stored frequencies stored in memory, then select the one closest to the detected frequency, and adjust the string to obtain the selected one of the stored frequencies. .

5. Therefore, first the microprocessor displays the selected frequency on the digital display 31. This is indicated by the number shown in the left digit of the display digit corresponding to the relevant string.

Thus, for example, on a six-string guitar, the top or base string could be designated by 1, and the remaining strings could be designated by numbers 2 through 6 in sequence. Furthermore, in the right digit, the microprocessor can display the corresponding note in the form of a letter to which that string is to be tuned. For example, in traditional IT,
The bass string has an absolute frequency of 82-4 i Hz.
It is tuned to the note E in the octave. Accordingly, the display on the digital display will show the letter of the relevant string to an experienced user and the relevant string number to a novice user.

6. At the same time as providing the display, the microprocessor generates a signal on line 41 or 42 depending on whether the calculated frequency is higher or lower than the required storage frequency. The motor continues to be driven while continuing to sample tones, which is repeated every 5 to 10 cycles as required. When the detected frequency reaches the selected frequency, the output to line 41 or 42 is stopped and the motor is stopped. At the same time, the microprocessor refraining from outputting on line 41 or 42 provides output to digital display 31 to illuminate the periodic mark shown at 31A.

Z Upon detection of a subsequent tone, the microprocessor repeats the steps to tune the next string selected by the user to strum, again selecting the frequency closest to the detected frequency.

8. Observing the displayed string being tuned as shown on said digital display, the user may determine that the displayed string is not the string being tuned and that the string being tuned is far away from the desired frequency. Once known, the user can activate switch 39 to override the selection of the closest frequency.

Thus, repeated depressions of switch 39 will cycle through the strings associated with the number of strings on the instrument. Therefore, for example, in the case of a six-string guitar, each time the switch 39 is pressed, the selected string moves to the next string numbered 1 to 6, and after 6, returns to the first string. In this way, the user can preselect the string frequency to be used by the microprocessor if the string is found to be far off its desired frequency. In this way, the device can be used for the initial winding 9 of the string from a very loose condition to the required tension to give the correct frequency.

9 Switch 38 can be activated by the user to select one of several different states of the microprocessor. Each of these states can be used to maintain the desired frequencies for different instruments or different tunings of the instrument. The different states are numbered from 00 to 99 so that the required states for various different instruments tuned in different ways can be stored in the device.

Accordingly, the device can be used with many different instruments including 6-string guitars, 12-string guitars, 4-string panchauds, 5-string banjo mandolins, and others. If desired, different tunings for the instrument can be recorded under different numbered states.

10. As generally accepted in traditional musical exercises,
Note A in the sixth octave has a frequency of 440.00 Hz. However, other tunings are also possible.
The frequencies of all notes are offset according to the base note A offset. In some cases a 438 Hg1 tuning may be used, and in other cases a 445 Hj tuning. This condition can be input to the microprocessor by recording the required frequency as a different state for each instrument under different tunings, or by providing one state that allows selection of the desired fundamental frequency.

11. In one configuration, the microprocessor stores all said frequencies in memory so that when a desired mode or state is selected, the associated frequencies are brought forward. In another configuration, the frequency can be calculated from the fundamental frequency or fundamental frequencies stored in memory.

The latter configuration reduces the amount of memory required and therefore may be advantageous in certain situations.

This state is shown at 70- in FIG. 4.

The device of FIG. 1 is used in such a way that the motor and power supply are separated from the microprocessor and act simply on a spool that can be used independently under the control of the user's fingers simply on the appropriate push button. You can also.

Next, we return to another configuration shown in FIG. A typical electric electret microphone with a voltage of 20 to 100 mV.
approx. 5 pre-amplified to match the level of
Gives a mV signal. The gain is rolled off at low frequencies above 2.2. .

Low sound output for G, B and 8th strings is approximately 60.5 crfL
Requires ~15.2 cm (12-6 inches) of guitar-to-microphone separation.

A VC2 active filter is used to amplify the signal and reduce harmonic components and high frequency noise. K,
A 4-pole narrowband filter is used at 140Hz to process the A and 9th strings. It consists of two cascading bipolar sections. Six filters at 305Hz are used on the G, B and 8th strings. The corner frequencies are carefully chosen to optimize fundamental signal strength versus harmonic content.

A commercially available 4th order Butterworth filter chip can be used as an alternative filter configuration.

The outputs from the two filters are selected by simple diode-r switches controlled by a microprocessor. The select signal is capacitively coupled to a comparator with hysteresis and input to a microprocessor interrupt line. The signal at this point is converted to a Schmitt Triangle C5V square waveform with a transition at approximately the signal zero crossing of a strummed note.

The microprocessor uses these transitions to determine the note duration and uses an oscillator to generate a number of pulses proportional to the note duration.

Intel 806 with external FROM at standard configuration pressure
1 microprocessor is used. Two bins are saved for programming to different tuner models (eg, 6 string, bass, mandolin, etc.) or as desired. The power/mo switch is sensed on bin 2 and initiates the reference function described below.

Eight LEDs are provided to indicate the string being tuned (E, A, D, G, B, K) and status (sharp, flat). To make parts count economical, they are activated using only 5 wires of the 74HC244)-'' driver.The remaining 6 wires are connected to the power supply (1 wire) and motor (
2 wires).

The tuner is powered by a 9v battery. It is reverse protected by a diode and is regulated to provide 5V DC for use by analog and digital electronic equipment. Six diodes are used to generate the reference voltage (Vbias) for the operational amplifier. Furthermore, this design allows 9V to be supplied from the motor drive unit via the connection cable.

The motor drive receives forward and reverse control signals from the tuner,
Drive the motor accordingly. Power is supplied to the H-bridge from an internal 9V battery or an external DC adapter. Adapters must be carefully selected to avoid the possibility of connecting 60 Hz interference to the filter circuit. Laboratory tests have resulted in battery life of 1-2 weeks with very intermittent duty cycles, but the motor drive current is on the order of 600 rnh. A conventional four conductor telephone cable is used to link the motor drive to the itertuner unit.

In operation of the device shown in FIG. 5, the device can initially simply be set to the on position by activating the switch, at which time the tuner will automatically initialize at the 440 Hg "mu" reference. To change the reference from 440 Hz to any other available reference, move the control switch to SET and the LID will then turn on. When the ID corresponding to the new desired criterion is illuminated, the control switch is moved to REF and the LED associated with the now selected criterion is illuminated. Next, the switch returns to the ON position υ, and the tuning proceeds as follows. Of course, if it is necessary to use the A criterion at 440 Hz, no action is required to change the selection criterion.

With the device in the ON position, Ude engages and strums the string, preferably at or near the 12th fret;
Musical notes are therefore generated from the strings and can be received into the unit via a microphone or a direct plug connected to an electronic guitar. The unit therefore monitors this human powered node and attempts to distinguish legitimate notes from any background noise. The filter reduces the harmonic content of the signal, leaving only the fundamental note of interest active, which is converted into a square wave by a Schmitt trigger, and the filtered note is analyzed by a microprocessor.

The microprocessor operates to compare the analyzed note to reference frequencies stored for individual strings and select the reference frequency that is closest to the frequency of the analyzed note.

If a string is thus identified, the LED associated with that string will illuminate and the unit will begin a tuning operation. Tuning is divided into an initial rough tune mode and a subsequent fine tune mode.

In rough tune mode, the microprocessor operates to pulse the motor drive system in a clockwise or counterclockwise direction and simultaneously illuminates the LEDs associated with the sharp/flat display. The rough tune mode continues until the measured period variation is less than 128 μB. However, before any pulse is generated, a microprocessor samples multiple wavelengths, appropriately samples several such wavelengths that fall within a predetermined width, and averages them before the pulse is generated. ensure that the This ensures that the motor is not driven by the detection of external noise.

Once rough tune mode is complete, the unit moves to fine tune mode. In this mode, the unit averages several synchronous samples to eliminate noise and data effects and arrive at an accurate period measurement. The pulses generated by the microprocessor are calculated to have a period proportional to the difference between the measured frequency and the target frequency, such that the period of the pulse is reduced when the measured frequency approaches the target frequency. Thus, the microprocessor repeatedly samples the frequency of the notes being generated and after each sampling drives the motor with one pulse of length determined by the sampling. The motor and display are driven until the periodic error is within desired tolerances. As the string approaches tune, the motor pulses narrow because the motor is pulsated for a number of μS periods proportional to the measured period error after each average period.

In many cases, the generated motor pulses can cause an overshoot of the target frequency, in which case the motor is pulsed in the opposite direction and the string gradually reaches the desired target frequency with pulses of reduced length. .

If the performer knows that the associated string is far from its desired tuning or target frequency, the performer can select the target frequency by moving the switch to the SET position, then the IJD will Lights up sequentially. When the LED corresponding to the desired string or target frequency is illuminated, the control switch moves to the ON position, thereby setting the microprocessor to that target frequency regardless of the difference between the detected frequency and the target frequency. . This can be used when applying a new string and wishing to unwind it to the required tension.

Since various modifications may be made to the invention as described above, and various different embodiments are possible within the spirit and scope of the claims, everything contained in the specification is for illustrative purposes only and is not limited thereto. isn't it.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the appearance of an embodiment of the present invention, FIG. 2 is a schematic diagram of an embodiment of the apparatus of the present invention, and FIG. 6 is another configuration according to the present invention. FIG. 4 is a schematic flow diagram of a program of the microprocessor unit, and FIG. 5 is a schematic diagram showing an external unit having a further configuration. [Explanation of reference symbols] 10...Case 11, . 25.54...Battery part 13.34.57...Microphone 14.38.3
9.60.61...Switch 15.58...Socket 16...Wire 17.52...Grip body 18...Head en P 19.43.53...Motor 20...Shaft 21.50...Head 2...Push button 3...Key 4...Guitar head 0...Microprocessor 1.56...Display 5...Connector 9...Power switch

Claims (1)

[Scope of Claims] (1) A tuning device for a stringed instrument having a plurality of spools that are rotated to change the frequency of notes generated from the strings when strummed by changing the tension of the associated strings, the device being hand-held. a head member extending outwardly from the body and configured to releasably engage one of the pegs of the instrument, the body being independent of the instrument and capable of being used as desired. a head member is movable to independently engage each spool; a motor is mounted within the body to drive and rotate the head member to rotate the one spool; and is arranged to rotate in the direction and counterclockwise to tighten or loosen the string as required, and sensor means are arranged to detect when strumming and the notes generated from the string and calculate the fundamental frequency of the note. means are provided for storing a plurality of predetermined desired frequencies, each associated with each string of the instrument, and means are provided for storing a plurality of predetermined desired frequencies, each of which is associated with a respective string of the instrument, and comparing the fundamental frequency of a note on a string with said plurality of predetermined desired frequencies. Comparator means is arranged for selecting one of the frequencies closest to the fundamental frequency from the desired frequencies;
A stringed instrument tuning device comprising means for driving and rotating a motor in a direction that converts the fundamental frequency of a note on a string to one of said frequencies. (2) The invention according to claim 1, further comprising visual indicator means for displaying each of the plurality of predetermined desired frequencies, wherein the comparator means is configured to cause the indicator means to display the selected predetermined frequency. A stringed instrument tuning device. (3) The invention according to claim 1, wherein the visual indicator means is configured to provide an indication when a note on the string is equal to a predetermined frequency. (4) The invention according to claim 1, The storage means is configured to provide a set of predetermined frequencies for each string, each set of all strings being associated with one of a plurality of reference frequencies; A stringed instrument tuning device provided with manual activation switch means for selecting. (5) A stringed instrument tuning device according to claim 1, further comprising manual activation switch means for disabling said comparator means and selecting one of said stored frequencies. (6) The invention according to claim 1, wherein the sensor means includes means configured to generate a square wave from a string tone, and the comparator means detects edges of the square wave and calculates a period between the edges. A stringed instrument tuning device including means for tuning. 7. The apparatus of claim 1, wherein the head member includes a slotted opening adapted to fit loosely over a conventional key of a stringed instrument. (8) By turning each, change the tension of the associated string,
A device for use in tuning a stringed instrument having a plurality of spools that change the frequency of notes produced by the strings when strummed, the device having a body that can be held in the hand and a body that extends outwardly from the body to tune the instrument. a head member configured to releasably engage one of the spools, the body being independent of the instrument and movable as desired so that the head member can independently engage each spool; A motor is mounted within the main body and is arranged to drive and rotate the head member to rotate the one spool, and the motor rotates clockwise and counterclockwise to tension the string as desired. sensor means are arranged to detect notes arising from the strings when strummed and calculate the fundamental frequency of the notes, each sensor means being arranged to detect a plurality of predetermined frequencies, each associated with each string of the instrument. means are provided for storing a desired frequency of a note on the string and for rotating the motor in a direction to change the fundamental frequency of a note on the string to said one frequency by comparing the fundamental frequency of the note on the string with one of said predetermined desired frequencies; Comparator means are arranged, said comparator means being configured to detect the magnitude of the difference between said fundamental frequency and said one of said predetermined desired frequencies to rotate said motor with pulses of different duration. , a string instrument tuning device where the duration of each pulse depends on the magnitude of the difference. (9) The invention according to claim 8, further comprising visual indicator means for indicating each of the plurality of predetermined desired frequencies, wherein the comparator means is configured to cause the indicator means to display the selected predetermined frequency. A stringed instrument tuning device. 10. The apparatus of claim 8, wherein the visual indicator means is configured to provide an indication when a note on the string is equal to a predetermined frequency. (11) In the invention according to claim 8, the storage means is configured to give one set of predetermined frequencies to each string, and each set of all strings is associated with one of a plurality of reference frequencies. , a stringed instrument tuning device comprising manual activation switch means for selecting one of said reference frequencies. (12) In the invention according to claim 8, the comparator means compares the fundamental frequency of the note on the string with each of the predetermined required frequencies, and selects one of the frequencies closest to the fundamental frequency from the predetermined required frequencies. a manual activation switch configured to select one of the stored frequencies and configured to override the comparator means and select one of the stored frequencies. (13) In the invention according to claim 1, the sensor means includes means configured to generate a rectangular wave from the fundamental frequency of the string, and the comparator means detects the edges of the rectangular wave and calculates the period between the edges. A string instrument tuning device including means for generating a signal representing the string. 14. A stringed instrument tuning device according to claim 1, wherein the header member includes a groove-shaped opening arranged to loosely fit over a conventional key of a stringed instrument. (15) In the invention according to claim 8, when the comparator means detects a musical note, it detects and calculates the fundamental frequency of the musical note over a plurality of cycles of the musical note, and rotates the motor only after the plurality of cycles. A stringed instrument tuning device consisting of.