KR100815832B1 - Golf swing tempo measurement system - Google Patents

Abstract

A biofeedback system comprising an elongate member is provided for feeding back a sound indicative of the swing tempo of the elongate member. The system includes a plurality of acceleration measuring devices adapted to measure acceleration at a plurality of positions along the elongated member; A first microcontroller for processing the measured acceleration signal to reduce the effect of gravity and for forming a digital number comprising a plurality of bits, with respect to a rotational angular velocity squared by power; A second microcontroller for receiving a digital number, associating the bit with a plurality of groups each having an amplitude value representing an associated tone composition and bit content, and for forming a command representing the tone composition and amplitude value; A synthesizer in response to the command, the synthesizer generating an audio signal; And means for outputting an audio signal.

Golf Swing, Angular Speed, Tempo, Microcontroller, Biofeedback

Description

GOLF SWING TEMPO MEASUREMENT SYSTEM

The present invention relates to an apparatus for providing an audio biofeedback associated with the operation or tempo of a golf swing.

In golf, tennis, fishing, bowling, baseball, etc., the key to any reproducible swing is whether it is a constant tempo, and if a player takes the correct swing for a given game situation, he / she repeats the swing in the same situation. You should be able to. A constant tempo indicates that speed changes throughout the swing are repeated between swings.

It is usually very difficult to recognize the tempo of the swing in sports. Athletes' perception of being fast and slow can change from day to day, every second depending on mood, adrenaline levels, and the like. It is more complicated to achieve a certain performance by the fact that visual help usually requires a shift in attention away from more important focuses. In addition, training generally focuses on tactile and visual perception by observers other than athletes, and it is difficult to communicate problems with swing speed variation and tempo. Therefore, a quantitative method of recognizing tempo without interfering with the motion of the swing is a useful exercise training / performance aid.

The natural path to perceiving the tempo is through sound and music, with the advantage that the player can focus on his / her swing. With a wide range of exposure to music, universal in all training, it is possible to detect tempo-related timing from an acoustic perceptual perspective.

The momentary motion of the golf swing occurs faster than it can be consciously controlled, and the controlled speed and tempo are important for successful reproducible performance. In addition, muscle memory that yields an unconscious harmony of muscle activity can be learned by repetitive practice of the correct tempo. Thus, the auditory path is a desirable mechanism for subconsciously providing swing tempo information without disturbing the athlete.

Golf swing tempo represents a change in the speed of a golf club by intersecting a circular path between through impact and follow through through a back swing, a ball strike. Since the golf swing is controlled by the motion of the circular path, the tempo of the swing represents the tempo of the time history or the angular velocity of the club. In addition, because the centripetal acceleration of the body moving in circular motion is a function of the angular velocity of the body, an accelerometer mounted near the golf club head provides a signal that can be used to indicate the tempo.

The centripetal acceleration at a particular point on the swing club can be measured with an accelerometer at the point of interest, the sensing axis of which is aligned along the axis of the shaft. In general, this centripetal acceleration (a _c ) can be used to calculate the instantaneous measurement of the square of the angular velocity of the club through the relationship a _c = ω ² r, where ω is the angular velocity of the club shaft and r is the accelerometer's movement. Is the effective radius.

The prior art appears to recognize that measurement errors can occur due to the effects of gravity. Error signals that can be confused with the desired centripetal acceleration signal can be reduced or eliminated by performing differential measurements using two accelerometers placed at different positions along the axis of the shaft, each accelerometer sensing the same gravitational acceleration However, it detects the centripetal acceleration scale according to the effective radius of motion.

However, it was somewhat difficult to get full benefit from the use of accelerometers and audio feedback mounted on golf clubs, but this is not a lack of effort. For example, US Pat. No. 6,261,102 discloses converting the output of an accelerometer into an audio signal for biofeedback. Place the accelerometer along the club axis, measure the centripetal acceleration, and determine the square of the angular velocity of the club from this value. Then, a signal proportional to the square of the angular velocity of the club is converted into a frequency and supplied to the person as an audio signal. Unfortunately, there is a perceived tendency to produce an unpleasant "chirp like" sound because of deficiencies in the compensation for the effects of gravity and large speed changes during the golf swing.

Two other related prior art patents have similar drawbacks. Specifically, U.S. Patent No. 5,233,544 issued to Kobayashi, which describes the use of multiple accelerometers along a golf club shaft, does not recognize the potential for sound quality problems, and the multiple tonal scales as provided herein. It does not describe or limit its use. Also, Kobayashi uses an angular velocity signal rather than an angular velocity squared signal and therefore does not provide a sensitivity gain of the velocity squared signal.

U.S. Patent No. 5,694,340 to Kim similarly describes the use of multiple accelerometers to generate an acceleration signal, but fails to explain, present or recognize the benefits of multiple accelerometers to eliminate the harmful effects of gravity. have. Also, although Kim's patent uses multiple frequencies, these different frequencies are used to distinguish between the three axes, and are not intended to improve the tonal quality of the sound or to eliminate the chirp.

Thus, further improvements in the prior art are needed. In particular, it has been improved to eliminate or at least reduce the effects of linear accelerations (not due to rotational movement), such as gravity, which occur along the axis of the golf club, and produce a pleasant sound whose tone composition and amplitude vary to represent the tempo. There is a need to provide a biofeedback system for athletic equipment such as golf clubs, such as by way of non-limiting example, using angular velocity squared signals for sonification and increased sensitivity. The present invention overcomes the above mentioned drawbacks and attains the objects and advantages set out herein.

Therefore, it is an object of the present invention to overcome the perceived deficiencies of the prior art.

Another object of the present invention is to provide an improved arrangement of measuring devices which is used to counteract the effects of gravity, thus providing an improved indicator of swing tempo.

Another object of the present invention is to provide improved sensitivity for measuring changes in tempo using signals related to angular velocity squared signals.

Another object of the present invention is to provide improved audio feedback using pleasant tonal composition and amplitude characteristics in the ear.

It is a further object of the present invention to provide a system in which the measured signal or information and commands derived from the measured signal can be stored for later reproduction and analysis.

It is yet another object of the present invention to provide an improved audio feedback path that uses a radio link to carry biofeedback signals.

Generally speaking, and in accordance with the present invention, a biofeedback system is provided that includes an elongate member for feeding back a sound indicative of the swing tempo of the elongate member. In a preferred embodiment, the system comprises a plurality of acceleration measuring devices suitable for measuring acceleration at a plurality of positions along the elongate member; A first microcontroller for processing the measured acceleration signal to reduce the effect of gravity and for forming a digital number comprising a plurality of bits, relating to rotational angular velocity squared by power; A second microcontroller for receiving a digital number, associating the bits with a plurality of groups each having an associated amplitude composition and an amplitude value representing the bit content, and forming a command representing the tonal composition and amplitude values ; A synthesizer for generating an audio signal in response to the command; And means for outputting an audio signal.

In another preferred embodiment, the present invention provides a method for generating a plurality of acceleration signals representing acceleration of an elongate member at different locations of the elongate member; Processing the acceleration signal to reduce the contribution of gravity; Forming a sequence of digital samples of the processed acceleration signal, each of the plurality of bits associated with a rotational angular velocity squared to a power; Forming a group of a plurality of bits in a sample each having an associated tonal composition and an amplitude value associated with the digital values of the group; Generating instructions for synthesizing a sound indicative of the tonal composition and the amplitude of the group; And feeding back the synthesized sound.

In another embodiment, a system of the present invention includes a plurality of sensors coupled to an elongate member to direct a digital signal indicative of the movement of the elongate member; Process the signal to reduce the effects of gravity, generate a multi-bit digital number representing an angular velocity squared to a power, associate a bit with a plurality of groups each having an associated pitch composition and amplitude representing the bit content, Means for forming a command indicative of a tonal composition and an amplitude value; A synthesizer for generating an audio signal in response to the command; And means for outputting an audio signal.

In an alternative method, the present invention provides a method comprising the steps of providing a plurality of sensors mounted along an elongate member to derive a digital signal indicative of the movement of the elongate member; Processing the signal to remove or reduce the effects of gravity to produce a multi-bit digital number representing an angular velocity squared at power in at least two locations along the elongated member, and the associated tonal composition representing the bit content and Mapping to a plurality of groups each having an amplitude; Synthesizing an acoustic signal having a tone composition associated with the group and an amplitude indicative of a bit value of the group; And outputting an audio signal.

In another embodiment, a biofeedback system is provided for converting the kinetic characteristics of an elongate member into acoustic, comprising: a plurality of sensors disposed along the elongate member to capture kinetic parameters as multi-bit digital numbers; A processor for mapping each bit to a plurality of groups each having an amplitude representing the associated tone composition and the bit content; A synthesizer for generating an audio signal in response to the mapped bit; And means for outputting an audio signal. In a related method, the present invention provides a method comprising the steps of providing a plurality of sensors disposed along an elongate member to capture motion characteristics of the elongate member as a multi-bit digital number; Mapping each bit of the digital number into a plurality of groups each having an associated pitch composition and an amplitude representing the bit content; Synthesizing an acoustic signal in response to the mapped bits to produce a signal having an amplitude representing the tone content and bit content associated with the group; And outputting a signal.

In certain embodiments, the elongate member is a golf club.

1 is an illustration of a biofeedback system constructed in accordance with the present invention.

2 is a block diagram of an electronic device disposed in a golf club of the preferred embodiment of the present invention.

3 is a sketch used for the analysis of a golf swing using a golf club, but equally applicable to the analysis of a swing of any elongate member, such as, for example, a tennis racket.

4 is a typical plot of angular velocity squared for the configuration of FIG.

5 is a typical plot of angular velocity for the configuration of FIG.

6 is a block diagram of a processor portion of a preferred embodiment of the present invention.

7 is a plot of the amplitude characteristics of a single tone group.

8 is a plot of the amplitude characteristics of all tonal groups used to represent the 12 bit digital data of the present invention.

Reference is first made to FIGS. 1 and 2, in which a biofeedback system constructed in accordance with the present invention is shown at 100 and generally shown a golf club constructed in accordance with the present invention, shown generally at 200. Since the present invention is also a system for providing audio feedback with golf club 200, system 100 generally includes a processor unit shown generally at 300 and a monitor generally shown at 250. Preferably, both are wirelessly connected to each other and / or club 200 in a preferred embodiment.

Golf club 200 generally includes an elongate member, shown at 215, the elongate member itself may include at least a shaft and additionally may include club head 230. The first accelerometer 220 and the second accelerometer 225 are coupled to the member 215. With the swing of elongate member 215, accelerometers 220, 225 monitor the acceleration along the axis of member 215. Preferably located at member 215 is an additional circuit, generally indicated at 245, which comprises two A / D converters 254, 255 operatively connected to accelerometers 220, 225, respectively; Microprocessor 260 coupled to transducers 254 and 255 and a wireless transceiver 265 coupled to the output of microcontroller 260. The microprocessor 260 takes the difference in the digitized output of the accelerometers 220 and 225 and transmits this information to the processor unit 300 via the antenna 235. Clearly, the accelerometer provided on the club head is still considered to be an accelerometer along an elongated member.

The processor 300 receives the data transmitted via the antenna 315 and, after amplifying the signal as described below, outputs the biofeedback audio signal to the speaker 355 or the monitor 250 in a known manner. do. The monitor 250 includes an ear cover 252 and a belt / pocket mount receiver 256. In alternative embodiments, the user may wear an integrated receiver and headset.

As a general background, a swing analysis parameter, indicated at 250, is now shown, and golf club 200 is shown with accelerometers 220, 225 having its measurement axis aligned with the golf club axis. See. A player (not shown) having an arm, indicated by reference numeral 105, and a waist, indicated by reference numeral 110, attempts to strike the ball 140, circumferentially around waist 110 at an angular velocity of ωradians per second. The circular motion 135 swings the club 200 with the head 230.

The centripetal acceleration at a particular point on the swinging club can be measured with an accelerometer at the point of interest, with the sensing axis of the accelerometer aligned along the axis of the member. In general, the centripetal acceleration a _c yields an instant measurement of the angular velocity of the club through the relationship a _c = ω ^2r , where ω is the angular velocity of the club head (assuming accelerometer at or near the head), r is the effective radius within which the accelerometer travels.

Note that in order to estimate the maximum magnitude of this acceleration, the player can achieve a club head speed of about 100 mph. The typical radius that forms the circular motion that the club head travels is on the order of 5 feet, but the accelerometer is typically placed at about 4.5 feet. This yields a maximum measured centripetal acceleration of about 1200 m / s ² . Normalization by gravity acceleration of 9.8 m / s ² is more common, which yields about 120 g. This is useful as a means of defining the required dynamic range of the measurement.

The measurement error is due to the influence of gravity. The accelerometer measures all of the acceleration experienced along its sensing axis. Earth's gravitational attraction produces a constant acceleration of 9.8 m / s ² , which is denoted as 1 g and points to the center of the earth. The direction of gravity acceleration is indicated by the arrow "g", which defines the vertical direction in the present invention.

As shown in FIG. 3, the orientation of the golf club 200 relative to the direction of gravity acceleration g changes as the golf club 230 moves along the path 135. This varying orientation causes time varying error signals related to gravitational acceleration to appear at the output of the accelerometers 225, 220.

Error signals that may be confused with the required centripetal acceleration signals are eliminated by performing differential measurements using data from accelerometers 220 and 225 disposed in r ₁ and r ₂ , respectively. As will be appreciated by those skilled in the art, each accelerometer senses the same gravitational acceleration, while the centripetal acceleration is perceived as the effective radius of motion. To summarize these states,

(1)

(One)

Here, a ₁ is the acceleration measured by the accelerometer 220.

(2)

(2)

은 부재의 축을 따른 중력 가속도의 크기를 나타낸다. 수학식 (1) 및 (2)의 차는 이하를 산출한다.Here, a ₂ is the acceleration measured by the accelerometer 225.

Represents the magnitude of the acceleration of gravity along the axis of the member. The difference between the equations (1) and (2) calculates the following.

a ₂ -a ₂ = ω ² (r ₂ -r ₁ ) (3)

It is proportional to ω ² (ie, angular velocity squared) and independent of gravity acceleration, and (r ₂ -r ₁ ) is a fixed number.

From Equation 3, it is clear that maximizing the separation distance between the two accelerometers optimizes the resulting signal. This suggests placing one accelerometer at or near the gripping portion and placing the remainder at or near the head end, which is described in the preferred embodiment.

A typical plot of ω ² , the angular velocity squared signal, is shown in FIG. 4. The square root of the signal of FIG. 4 with an angular velocity ω is shown in FIG. 5. The considerations of FIGS. 4 and 5 show that the use of the ω ² signal yields a larger output level change for improved sensitivity and swing speed changes. It should also be noted that ω ² is a measure of the rotational kinetic energy of the club.

The present invention provides a method of sounding ω ² by mapping or associating a bit of a 12-bit digital representation of a substantial instantaneous acceleration deviation value into an interval or group of bits, and providing each group with its own "sound", and allowing one or more instruments to Play a chord or note. Providing each group with its own sound and changing the magnitude of each sound as a function of the value of the bits in the group adds information to the audio biofeedback signal and aids in tempo identification. The overall effect is varying tonal composition and volume, while maintaining the harmonic relationship and avoiding frequency chirp.

A preferred embodiment of the present invention uses a MIDI wavetable generator to generate a unique sound for the selected group.

Referring again to FIGS. 1 and 2, since the accelerometer 225 is disposed closer to the club head 230, the higher centripetal acceleration of the two centripetal accelerations is read. The analog outputs of the accelerometers are fed to A / D converters 254 and 255 where they are converted into digital data streams and fed to microprocessor 260 for processing via serial link 262. A preferred embodiment includes a Microchip MCP3201 12-bit A / D converter to convert the analog output of the accelerometer into a digital data stream supplied to microprocessor 260, where the microprocessor is a Microchip 8-bit microcontroller, the PIC 16F873A.

The microprocessor 260 performs the subtraction of the acceleration readings and formats the resulting 12-bit NRZ data for transmission to the processor 300 by the transceiver 265. In alternative embodiments, the subtraction operation is performed at processor 300.

The transceiver 265 is preferably a Chipcon CC1000 configured to receive NRZ serial data from the microprocessor 260, reformat the data into synchronous Manchester coding, and feed the antenna 235 at 915 MHz. Initialization values, including data formatting, frequency selection, and the like, are stored in flash memory within the microprocessor 260 and supplied to the transceiver 265 by the serial link 266. Acceleration data from microcontroller 260 is transmitted to transceiver 265 by serial link 264.

The selection of an appropriate accelerometer for the preferred embodiment proceeds as follows. As mentioned above, in an accelerometer mounted about 4.5 feet from the grip radius of a typical radius, a club head speed of about 100 mph, and a grip end of the member 215, forming a circular motion of about 5 feet, the acceleration by the accelerometer 225 is An acceleration of about 1200 m / s ² or about 120 g. Thus, preferred accelerometers are those with a g range of 120 g, such as Analog Devices ADXL 193 (AD 22282). In an alternative embodiment for a golfer with a sufficiently faster swing, an accelerometer with a g range of 250 g, such as ADXL 193 (AD 22282), may be used, and in a third embodiment for a golfer with a relatively slow swing, the ADXL 78 Accelerometers with a range of 50 g such as (AD 22280) can be used. In alternative embodiments, the accelerometer 220 may have a lower rating than that of the accelerometer 225 because the accelerometer 220 is closer to the gripping portion 222, and therefore the accelerometer 225 is This is because they receive lower centripetal acceleration than they receive. In this latter embodiment, the output of accelerometer 220 is preferably scaled to facilitate subtraction of equations (1) and (2) to provide equation (3).

Alternatively, a plurality of accelerometers of this type are provided and selectable by a switch (not shown) on the club 200 so that the same club can have different golfers with significantly different swing speeds or significantly different swing speeds. It can be used by the same golfer under the conditions required. In another embodiment, the selection of the accelerometer may be performed by a wireless link between the transceiver 265 and the transceiver 330.

6 is a block diagram of circuitry within the processor 300. The 12 bit data transmitted by the transceiver 265 and the antenna 235 is received by the antenna 315, demodulated back to the NRZ code by the transceiver 330, and the microcontroller 335 via the NRZ serial stream. Supplied to. Serial bus 332, 334 provides communication between blocks 330, 335, serial bus 337 provides communication between blocks 335, 340, and bus 342 provides blocks ( Provide communication between 340 and 345.

Microcontroller 335, preferably PIC 16F873A, receives the 12-bit digital data stream, maps the bits of the 12-bit acceleration signal into six groups, groups 1-4 have 9 bits, and group 5 8 bits, group 6 contains 7 bits. The bits that form each group of the preferred embodiment are shown in Table 1.

group Forming bits One b ₈ -b ₀ 2 b ₉ -b ₁ 3 b ₁₀ -b ₂ 4 b ₁₁ -b ₃ 5 b ₁₁ -b ₄ 6 b ₁₁ -b ₅

The bits in each group are treated as one word, and the microcontroller 335 calculates the numerical value of the word. As an example, if the "word" b ₈ -b ₀ has the value 000001010, the value of the word is 10.

For groups with non-zero word values, the microcontroller 335 sends MIDI commands to the synthesizer 340 to " on " the tone (s) for a particular group and to switch the " on " group. Command to make the amplitude equal to a value proportional to the word value of the group. The MIDI commands thus generated are serially communicated to the synthesizer 340. Synthesizer 340 interprets the MIDI commands and converts them into a biofeedback signal as described further below. The preferred embodiment uses CRYSTAL single chip wavetable music synthesizer CS9236, which is universal MIDI compatible. In an alternative embodiment, tonal groups are prewritten, recalled from memory, and combined to form a synthesized biofeedback signal.

In a preferred embodiment, synthesizer 340 is programmed by microcontroller 335 to associate each group with a particular MIDI channel. Each MIDI channel contains two notes musically known as fifths in the preferred embodiment, and is programmed to play a particular chord that includes "root" and its full "pips." When using a pip with a fundamental frequency of f ₀ , the associated fifth is 1.5f ₀ . Other harmonic relationships may be switched by the panel controller 370 of FIG. In addition, alternative embodiments may utilize sets of notes with different harmonic relationships and / or sets of notes without harmonic relationships. The preferred instrument for all groups is rock organ, but different instruments for all groups or different instruments for each group may be selected by panel control 370.

Note group relationships or tonal compositions for the preferred embodiment are illustrated in Table 2, where C4 is intermediate C (about 261.6 Hz), C3 is below one octave (about 130.8 Hz), and C5 is one octave than intermediate C. Above (about 523.2 ms) and so on.

group MIDI channel root Pips frequency note frequency note One One f ₀ C3 1.5f ₀ G3 2 2 2f ₀ C4 3f ₀ G4 3 3 3f ₀ G4 4.5f ₀ D5 4 4 4f ₀ C5 6f ₀ G5 5 5 5f ₀ E5 7.5f ₀ B6 6 6 6f ₀ G5 9f ₀ D6

The amplitude (volume) of each MIDI channel is determined by the bit value of the corresponding group. As an example, in group 1, the volume is defined by bits b ₈ -b ₀ of a 12 bit full scale signal, where b ₀ is the least significant bit. When the word value of bits b ₈ -b ₀ is between 0 and 127, the output volume is set in proportion to the word value. When the value is between 128 and 255, the output volume is limited to a value proportional to 127. When the value is between 256 and 511, the output volume is set to be equal to (word value of bits in the 511-group) / 2. This yields, for example, a waveform for group 1 that descends to zero when the angular acceleration square increases up to a maximum of 127, stays at 127, then has a negative slope and again increases angular acceleration square further. This amplitude characteristic is shown in FIG.

This basic process is the same for all groups. Since each of groups 1-4 is formed by 9 bits, their respective amplitude curves follow that shown in FIG. Since group 5 is formed by 8 bits and group 6 is formed by 7 bits, their respective amplitude characteristics reach 127, but do not reverse direction but have a negative slope. The resulting pitch and volume integration for all groups is shown in FIG. 8. Pure effects are volume and tonal content that changes with the signal in a format that avoids frequency chirp while maintaining harmonic relationships.

Although Table 2 shows each code associated with a particular channel, an alternative embodiment provides multiple codes on one or more channels.

Processor 300 includes flash memory 365 for storing sounded data (in the form of MIDI instructions and 12-bit acceleration data). The former is used for playback during the practice session, and the 12 bit acceleration data is preferably used in conjunction with a home computer instead of the processor 300, or to understand and experiment with alternative acoustics and sound effects.

The information may be downloaded from processor 300 via data port 375, or in alternative embodiments, may be downloaded by removing the memory card. Similarly, at the player's choice, alternative sounding schemes may be uploaded to processor 300 via data port 375 and selected via control panel 370.

The output of synthesizer 340 is a digital data stream representing the acoustic angular velocity squared signal and a measure of the rotational kinetic energy of the club. This signal is supplied to the D / A converter 345 for conversion to analog values. This analog value is supplied to the audio amplifier 360 and to the speaker 355. Analog signals from the D / A converter 345 may also be available at a connector (not shown), which is optionally connected to a wireless transmitter 350 having an antenna 320. The wireless transmitter 350 uses transmission via radio waves, but in alternative embodiments, infrared signals are used.

Another feature of the invention is that golf swing curves having the general shape of FIG. 4 are superimposed, or otherwise compared to one another, to visually indicate (and compare) the swing tempo between repeated swings of a single user or between various users. It can provide. This information may then be stored and / or visually communicated to, for example, a user at home for later consideration. In this way, the user can, for example, analyze the golf swing (s) of professionals using the golf club 200 of the present invention.

Thus, it can be seen that the present invention provides a number of advantages not found in the prior art. By way of example, the present invention provides for the use of audio feedback using sounded angular velocity squared values, correction of angular velocity squared values for gravitational acceleration, and changes in tone composition and amplitude rather than abrupt frequencies.

While the invention has been specifically illustrated and described with respect to its preferred embodiments, those skilled in the art will understand that changes may be made in form and detail therein without departing from the spirit and scope of the invention. By way of example, where a microprocessor has the necessary speed, etc. to perform the methods and functions described above, all microprocessor functions may be provided in one unit. Therefore, the distribution of the above-mentioned components is an example, and is not restrictive. In a similar manner, although all references to powers that raise the angular rotational speed are mentioned as 2, the implementer should change this amount slightly, and the claims should not be limited thereto, and, therefore, at least substantially (even though) The exact one is preferred). Additionally, accelerometers disposed along the elongate member may be disposed in or on the member, both of which are included in the claims of the present invention. Finally, one can also consider that the sensor used is not physically mounted on the member, such as on a wall, for example, where the acceleration of the elongate member is measured from one or more physically separated sensors. The right to provide a claim is reserved.

Claims (12)

A biofeedback system comprising an elongate member for feeding back a sound indicative of the swing tempo of the elongated member, A plurality of acceleration measuring devices suitable for measuring acceleration at a plurality of positions along the elongate member; A first microcontroller for processing the measured acceleration signal to reduce the effect of gravity and for forming a digital number comprising a plurality of bits relating to a rotational angular velocity squared by power; A second microcontroller for receiving a digital number, associating the bits with a plurality of groups each having an amplitude value representing an associated tone composition and bit content, and for forming a command representing the tone composition and amplitude values; A synthesizer for generating an audio signal in response to the command; And And a means for outputting an audio signal. The biofeedback system of claim 1, wherein the power of which the rotational angular velocity is squared is at least substantially two. A method for feeding back a synthesized sound indicating a swing tempo of an elongate member, Generating a plurality of acceleration signals indicative of acceleration of the elongate member at different locations of the elongate member; Processing an acceleration signal to reduce the contribution of gravity in the signal; Forming a sequence of digital samples of the processed acceleration signal, each of the plurality of bits associated with a rotational angular velocity squared to a power; Forming a group of a plurality of bits in a sample, each having an associated pitch composition and amplitude value, associated with the digital number of the group; Generating instructions for synthesizing a sound indicative of the tonal composition and the amplitude of the group; And And feedbacking the synthesized sound. A feedback system comprising an elongated member for feeding back a sound indicative of the swing tempo of an elongated member, A plurality of sensors coupled to the elongate member for inducing a digital signal indicative of the movement of the elongate member; Process the signal to reduce the effects of gravity, generate a multi-bit digital number representing an angular velocity squared to a power, and associate the bit into a plurality of groups each having an associated pitch composition and an amplitude representing the bit content. Means for forming a command to indicate tonal composition and amplitude values; A synthesizer for generating an audio signal in response to the command; And A feedback system comprising means for outputting an audio signal. 5. The feedback system of claim 4, wherein the power of which the rotational angular velocity is squared is at least substantially two. A method for feeding back a sound indicative of the swing tempo of an elongate member, Providing a plurality of sensors mounted along the elongate member to derive a digital signal indicative of the movement of the elongate member; Processing the signal to remove or reduce the effect of gravity to produce a multi-bit digital number representing an angular velocity squared at power in at least two locations along the elongated member, and associated tonal composition and amplitude representing the bit content. Mapping the bits into a plurality of groups each having a; Synthesizing an acoustic signal having a tone composition associated with the group and an amplitude representing a bit value of the group; And Outputting an audio signal. A biofeedback system for converting kinetic characteristics of an elongated member into acoustic, A plurality of sensors disposed along the elongate member to capture motion parameters as a multi-bit digital number; A processor for mapping each digital number of bits into a plurality of groups, each having an amplitude representing the associated tonal composition and the bit content; A synthesizer for generating an audio signal in response to the mapped bit; And And a means for outputting an audio signal. A method for providing a biofeedback signal to a user using a sensor to capture movement characteristics of an elongate member, Providing a plurality of sensors disposed along the elongate member to capture motion characteristics of the elongate member as a multi-bit digital number; Mapping each digital number of bits into a plurality of groups each having an associated pitch composition and an amplitude representing the bit content; Synthesizing an acoustic signal in response to the mapped bits to produce a signal having an amplitude indicative of the tonal composition and bit content associated with the group; And Biofeedback signal providing method comprising the step of outputting a signal. The biofeedback system of claim 1, wherein the elongate member is a golf club. 5. The feedback system of claim 4, wherein the elongate member is a golf club. An elongate member for use in the biofeedback system according to claim 1. Elongate member for use in the biofeedback system according to claim 4.

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