JPH02298994A - Electronic harmonica for controlling sound synthesizer - Google Patents

Abstract

PURPOSE: To control an electronic sound synthesizer device by varying an electrical signal in response to the fluctuation of the flow rate and the direction of an air flow passing through a passage. CONSTITUTION: In a harmonica 11, an electrical distortion gage 21 is extended to the passage 17 to detect the direction and the flow rate of the air flow. The curvature 21a of the gage 21 in one direction increases electrical resistance as the function of a curved degree and the curvature 21b in an opposite direction gradually reduces the resistance. A signal generated by blowing into the passage 17 like this is distinguished from a signal generated by sucking in to detect the direction of the air flow to provide two music signal for each passage. Various modification can be selected by a switch 24 and in order to send a signal to a sound synthesizer 26, a multi-core signal cable 32 is plug-mounted to a jack 31, and provided with a little radio transmitter 33 with low power, having an antenna line 34. Thus, an electronic sound synthesizer is controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to musical instruments, and more particularly to electronic harmonicas for generating electrical signals for controlling electronic sound synthesizer devices.

To summarize the invention, a reedless harmonica generates control signals for a sound synthesizer located remotely from the harmonica, if desired. The harmonica body has multiple air passages, each producing a different musical note through a plurality of airflow sensors, which identify each note played, and through a transducer. Activate an electrical signal that dictates a change in the amplitude of the sound. In a preferred embodiment, the sensors are strain gauges and circuitry is provided to sequentially detect the electrical resistivity of each gauge in repeated scans, producing a repetitive sequence of digital code signals. The signals produced by the harmonica are used to control MIDI-equipped sound synthesizers or other types of electrically operated sound producing devices.

PRIOR ART AND ITS PROBLEMS The range of diverse sounds and amplitudes produced by traditional musical instruments is limited by their design and the physical limitations of the musician. For example, many conventional harmonicas are tuned to play a very limited range of whole intervals, and are unable to produce depressive or flattened semitones. Experienced players "bend" the note to approximate a semitone, but the result is undesirable. The volume or amplitude of the sound produced by a conventional harmonica is also limited by the musician's lung capacity.

Mechanically modified harmonicas were designed to allow the production of semitones as well as whole tones. J.

US Patent No. 2.565.100, issued August 21, 1951 to R. Tate, describes one example. Such instruments generally require the player to learn new mouth and hand movements that are substantially different from traditional techniques for playing a harmonica. These prior art instruments also cannot provide other desirable embellishments, such as adding chords or flattening intervals, or changing frequency, tonality, tempo, etc.

Prior efforts to increase the range of sound intensities obtainable from harmonicas were made in U.S. Patent No. 2.565.1, identified above.
As exemplified by No. 00, this included the installation of a microphone in the No. 1-Monica coupled to a loudspeaker through an electrical amplifier.

This is accompanied by the generation of music in the harmonica itself - and the reproduction of music in the loudspeaker position.

Feedback effects in such an arrangement disrupt the musical performance. Such a system also does not allow embellishment of the music produced by the harmonica, besides volume amplification.

Recent developments in electronic sound synthesizers include
Overcoming the limitations imposed by traditional instrument design and musicians' physical abilities. In many advanced forms,
Such systems are typically controlled by a digital microprocessor operated by a keyboard or other input device and can generate virtually any audible sound;
And produce a very diverse arbitrary decoration.

A harmonica structure capable of controlling such a synthesizer would considerably increase the range of musical options available to the harmonica player. Preferably, such an instrument does not have the feel of a traditional musical instrument and does not require substantial changes to conventional techniques for playing a harmonica.

Previous efforts to eliminate the need for reeds in traditional harmonicas and to substitute electrical elements to control electrical sound-producing devices do not extend the capabilities of traditional instruments.

A, 0. U.S. Pat. No. 2.455.032, issued November 30, 1948 to Williams, describes a construction in which the reeds are replaced by pressure-sensitive switches, each pressure-sensitive switch being activated by blowing into the harmonica. , and causing the tone generator to generate different ones of a series of predetermined audio frequencies. The switch is an on/off device and does not detect variations in the amplitude of the sound produced by the musician.

C, A, Hillairet et al. 1
U.S. Patent No. 13.516, granted June 23, 970.
, 320 also teaches the use of a series of air flow actuated switches to detect air flow in any of the harmonica passages. Activation of any switch changes the output frequency of an electrical oscillator coupled through an amplifier to an audio speaker to produce a sound corresponding to a particular air path. The circuit is an improvement on the Williams device in that the air velocity detector modulates the amplifier gain to vary the pre-produced volume in response to variations in the performer's breath flow rate. Additional controls allow the performer to shift octaves and introduce effects such as tremolo and semitone generation.

However, the device of US Pat. No. 3,516,320 does not generate separate electrical signals for each air passageway, independent of each other, that encode activation of the passageway by the musician and the desired amplitude of the sound. Tone sensitive switches are coupled in a single oscillator and do not respond accurately to simultaneous activation of two or more switches.

The separate amplitude detection means is a single detector that monitors all air passages together. These characteristics do not provide the utility needed to control sound synthesizers.

Further characteristics of previous electronic harmonicas are undesirable mechanical complexity and fragility in the airflow sensing mechanism. This makes such instruments expensive and susceptible to malfunctions due to effects such as saliva, lumps, shocks, etc.

The present invention is directed to overcoming one or more of the problems mentioned above.

SUMMARY OF THE INVENTION In one aspect, the present invention provides a body having a plurality of air passages, each corresponding to a different musical note, a power source, and a body responsive to the passage of a performer's breath through selected passages. and means for causing an electrically operated sound generating device to generate a selected sequence of musical tone signals. The harmonica is an airflow sensor that generates a separate electrical signal in response to airflow through each passageway, and that varies each of the signals individually in response to variations in airflow rate and direction in the passageway. Including means of knowledge. This provides a non-characteristic signal that identifies the note played and also identifies the amplitude at which the note is played. The harmonica further includes means for transmitting each of the tone characteristic signals to the tone production converter.

In another aspect of the invention, an electronic harmonica for controlling a tone synthesizer responsive to control signals identifying musical tones includes a plurality of spaced air passages and a plurality of electrical strain gauges in the body. It includes a main body having a. Each of the strain gauges is arranged to be bent by the airflow in a separate one of the passageways. The electrical resistivity of each gauge changes in response to such bending. By detecting air flow induced changes in the resistivity of each of the strain gauges, a means is provided for generating a control signal.

In yet another aspect, the invention provides an electronic harmonica for generating and transmitting digital control signals to a digital sound synthesizer. The harmonica body has a plurality of spaced air passages, each corresponding to a different musical tone, and further includes a DC voltage supply and a component for transferring digital control signals from the harmonica to the sound synthesizer. means. A plurality of strain gauges are secured to the body and each gauge has a flexure resilient element exposed to the air flow within a separate one of the air passages. Each strain gauge has an electrical resistance that changes in response to bending of the element and is coupled to a voltage supply.

Detector means detect the resistance change of each strain gage and generate a plurality of analog electrical signals, each indicative of a separate resistance change of the strain gage. The harmonica is
Further, means for repeatedly generating a sequence of digitally encoded addresses identifying successive strain gauges, an analog to digital converter, and a detector means responsive to receiving successive digitally encoded addresses. and means for reading out the repetitive sequence of analog signals. The resulting sequence of analog signals is directed to an analog-to-digital converter to produce a corresponding sequence of digital signal bytes that identify the amplitude of musical tones produced by the sound synthesizer.

Means are provided for adding an address code bit to each of the signal bytes to identify the musical tone that each byte characterizes. A sequence of bytes containing an address sign bit is directed to the transfer means.

The present invention provides a harmonica structure that is mechanically simple, damage resistant, and greatly expands the range of musical effects created by players of this new instrument. A harmonica generates electrical signals that continuously identify the air flow rate and direction in each air passageway, allowing an electronic sound synthesizer to generate a desired sound at a desired amplitude, and, if desired, a conventional acoustic harmonica. Modify, expand and embellish the music played in ways that are not achieved.

In its preferred form, the invention provides a variety of digital sound synthesizer systems or international standard MIDI
(Music Instrument Digital Interface) Generates electrical signals in digital form that allow arbitrary control of musical instruments equipped with a boat.

EXAMPLE Referring first to FIG. 81 of the drawings, an electronic harmonica II according to an embodiment of the invention has an external configuration closely resembling that of a conventional musical instrument, if desired, and is of approximately the same size. The main structural components include a flat body member 12 of rectangular profile and a cover plate 13 fixed to each side of the body member.

1 and 2 together, the front surface of the body member 12 has a rounded edge defining a mouthpiece 14;
It is then pierced by a row of spaced vents 16 through which the musician can blow or draw air in a conventional manner. Each air hole 16 corresponds to a musical tone of a different scale, such as in an acoustic harmonica. This embodiment has 12 air holes 1 to provide a chromatic harmonica.
6, but the instrument is also compressed with other numbers of air holes. For example, a diatonic harmonica requires only 10 wind holes.

2 and 3, each air hole 16 communicates with a separate one of a series of parallel air flow passageways 17 within body member I2, with the passageway extending through the back surface of the member. . An emulator (im+mulato) on the back of each passage 17
r) The flow restriction 18 has an opening 19 that is smaller than the passageway and is sized to create a flow resistance similar to that experienced by a player in the corresponding passageway of a conventional acoustic harmonica.

This resistance decreases progressively in the succession of passages I7, so that the opening 19 is of progressively increasing diameter in the succession of passages in the direction of the left or bass end of the instrument.

As discussed further in connection with the harmonica 11 electrical circuit, one of a series of electrical strain gauges 21 extends into each passageway 17 for sensing air flow, direction and flow rate. Strain gauge 21 is of a known type having a flexural elastic backing 22 and a thin film electrical resistor 23 affixed to the backing. Thus, bending of the backing causes the resistor to stretch or compress, producing a resistance change that is detected. The strain gauge 2I in this particular example is of the type that is pretensioned while being attached to the backing 22. As a result, 21a
Gauge 21 in one direction as shown in
Bending increases the electrical resistance as a function of the degree of bending, and movement in the opposite direction results in a gradual decrease in resistance, as shown at 21b. This allows the sound processing device coupled to the harmonica 11 to distinguish the signal produced by blowing into the passageway 17 from the signal produced by drawing air through the same passageway. Airflow direction is detected and provides two tone signals from each passage.

Referring again to FIG. 1, the manual control mechanism 24 in this particular embodiment of the harmonica 11 includes two push button switches 24a and 24b, accessible in the central region of the top cover plate 13. Switch 24 allows the performer to send a signal to the sound synthesizer to select various modifications that the system is programmed to perform, for example to introduce a chord or simulate another instrument note. . Additional switch 2
4 is provided in order to increase the number of opsins available to the harmonica player of this new instrument. Electrical connections to such switches are described below.

Another pushbutton 27 extends from the right side of the harmonica 11 for selectively producing a warning tone or a strange tone, as will be further discussed. A switch 28 for turning the harmonica 11 on and off is located on the back side of the main body member 12 in this embodiment.

The harmonica 11 is further provided with transmission means 29 for sending signals to a remote sound synthesizer 26. As shown in FIG. 1, such means 29 include:
A jack 31 located on the left side of the body member 12 includes a signal output port, into which a multicore electrical cable 32 is plugged to conduct the signal to the synthesizer 26. Other modes of signal transmission may also be used, such as fiber optic transmission of encoded optical signals. Eliminating the need for a form of cable 32 is advantageous in many instances, such as stage performances. For this purpose, the harmonica 11 is equipped with a small low power radio transmitter 3 having an antenna wire 34 extending a short distance along the exterior left side and rear side of the body member 12.
Contains 3.

Although the Wi4 diagram shows a compact acceptable detailed structure for the novel harmonica 11, the components may have other configurations,
It will be appreciated that other arrangements may also be made.

The body member 12 in this embodiment is a rectangular frame having a series of spaced partitions 36 extending from the front to the back to define the side walls of the air passageway 17. Preferably, a pair of partitions 36 are disposed between each passageway 17 and an adjacent passageway, with the pairs of partitions being slightly spaced apart, as better seen in FIG. This provides a thin buffering free air section between the continuous passageways 17 to prevent noise leakage. Bending of the partition 36 in one passage 17 8 resulting from changing the airflow is not transmitted to the adjacent passage and thus does not generate false signals in the adjacent passage.

Referring again to FIG. 4, many of the components of the electrical circuit of harmonica 11 are located on rectangular shelf 39 at the top of body member 12.
It is attached to or formed in a thin flat rectangular circuit board 38 located in the circuit board 38 . Function switch 24
Many components other than output port 31 and vibrato/tremolo control 41 are not shown in FIG. 4 because the size of the drawing does not allow depiction, and such components are Referenced hereinafter.

Another thin flat plate 42 is similarly located against the underside of the body member 12 and includes a sharp/seven rat switch 27 and a recharging switch 27 in the opposite end position. Possible electrical batteries 43 , in which case such components are housed in the body member at opposite ends of the series of partitions 36 .

Battery 43 has protruding needle-like terminals 44 that penetrate into positive and negative power terminal areas 46 of circuit board 38 due to assembly of the components. Body member I2 has an opening 47 providing access to a charging terminal port 48 of battery 43.

The strain gauges 21 in this embodiment consist of a continuous strip of material 49 integral with said backing material 22 of the individual gauges.
linked at the top by. In the assembled harmonica 11, the gauges 21 extend through a row of alignment slots 51 in the circuit board 38 and into a separate one of the air passages 17. Referring again to FIG. 2, the strip portion 49 of the strain gauge 21 assembly is attached to the circuit board 3.
It is tightened between two parallel insulated straight members 52 fixed to the top of the 8. The needle contact 53 is a single member 52
and provide electrical connections between strain gauge 21 and other circuit components.

Referring to Factor 2 and FIG. 4 together, in this embodiment the emulator flow restriction aperture 19 is inserted into a thin plate member 54 that extends along the back side of the body member 12 and fits into the slot 56.
A continuous opening formed in and located in order to be registered in the continuous airflow passage 17. The thin plate member 54 is
If it is desired to adjust the resistance to blowing or drawing experienced by the performer, another member having a different sized opening 19 may be substituted.

Referring specifically to FIG. 4 again, the insertion of the emulator lamella 54 into the slot 56 is followed by the insertion of a small infrared filter 57 in the end region of the slot. A filter 57 is located above the infrared window 58 in the body member 12 facing the Guiprate/tremolo control 41 . One part of the control 41 is an infrared light source 41a directed at the window 58, and another part of the control is an infrared detector 41b positioned to look into the window.

The player's hand is located behind the window 58 and the light source 41
The infrared rays are reflected from a to the detector 41b.

By moving the hand, the performer changes the amount of infrared radiation reflected by detector 41b, and thereby changes the output signal of the detector. As described further below, this signal causes the sound synthesizer to vibrate the sound frequencies, thereby creating a vibrato or tremolo effect. The filter 57 detects ambient visible light from the detector 41.
b to prevent distortion of the desired signal.

A cover 13 having a shallow disc shape fits over the top and bottom of the body member 12, closing off the internal components of the harmonica II and defining a hand grip. The cover 13 is
It has a pair of shallow notches 59 at each end to accommodate the ends of U-shaped spring-loaded clips 61 that secure the assembled components together in Figure tJ1. The ingredients are also
If the instrument is not intended to be disassembled, it may be held together by other fasteners, such as screws, or by adhesive.

Referring to Figure 5, the harmonica's electrical component receives and takes the DC operating voltage from the positive terminal B+ of the voltage regulator 63.
Voltage regulator 63 also has another terminal that defines a common conductor or chassis ground.

Battery 43 and on/off switch 28 are coupled to the input terminals of voltage regulator 63 in series relationship with each other.

Function control switch like strain gauge 21124H, warning sound/altering sound switch 27 and vibrato/tremolo control 41
are each on a separate one of 16 signal channels 67 through signal generation circuit 68. Channel 67 sequentially receives instantaneous input voltages from digital address decoder 64, which will be described further below. The sequence of instantaneous application of the B+ voltage to input terminal 66 of channel 67 is repeated continuously, while the instrument is preferably operated at a high repetition rate, i.e. at a frequency of 20 Hz in this particular example. . The high frequency scan of channel 67 is
It produces high quality sound because airflow changes are detected more quickly and in small increments than is possible at lower frequencies.

Each strain gauge 21, only one of which is shown in FIG. 5, is coupled between the input terminal 66 of the isolation channel 67 and chassis ground in series relationship with a fixed resistor 71. Thus, each gauge 21 and associated resistor 71 functions as a voltage divider, and during successive energizations of channel 67, the voltage at the junction 72 between the gauge and resistor is equal to Caused by variations in the air flow rate through the passageway I; changes in response to changes in gauge resistivity. The variable voltage pulses from each circuit branch 72 are transferred to a separate input terminal 73 of a signal detection circuit 74.

Within the signal detection circuit 74, each input terminal 73 is coupled through an input resistor 77 to the negative or inverting input of one of a series of voltage amplifiers 76, with the positive or non-inverting input of the amplifier being coupled to ground through another resistor 78. connected to. Feedback resistor 79 fixes the gain of amplifier 76 in a known manner.

The output pulses from amplifier 76 are passed through a series of buffer amplifiers 82.
through one of the output terminals 81 of the detection circuit 74. In particular, the output of amplifier 76 is coupled through capacitor 83 to the non-inverting input of buffer amplifier 82, and the input of capacitor 83 is also coupled to ground through resistor 84. The inverting input of the buffer amplifier 82 is
It is coupled to chassis ground through another resistor 86 and to the output of the amplifier through a feedback resistor 87.

Thus, each buffer amplifier 82 of the transmitter circuit 74 transfers a voltage pulse to the associated output terminal 81 each time the decoder 64 energizes the associated signal channel 67, the amplitude of the pulse being at the time of the strobe. Indicates the instantaneous rate of airflow through the harmonica air passage.

In order to generate the viprato/tremolo signal within the signal generation circuit 68, the infrared detector 41b is connected to the decoder terminal 66.
and chassis ground in series with a voltage dropping resistor 89. 7, the junction 91 between the ode detector 41b and the resistor 89 connects the associated one in the detection circuit 74 through an amplifier circuit 92b similar to the circuit 92a described above with reference to the signal channel of the strain gauge 21. It is coupled to output terminal 81 . An infrared light source 41a, which is a light emitting diode, is connected between the same input terminal 66 and chassis ground.

Thus, diodes 41a and 41b are both instantaneously energized each time decoder 64 applies an instantaneous voltage to the associated input terminal 66. The amount of infrared light from diode 41a received by diode 41b depends, in the manner described above, on the movement of the harmonica player's hand. Diode detector 41b and resistor 89 are actually voltage dividers.

As a result, because the resistance of diode 41b changes in response to variations in the amount of infrared light received, the magnitude of the continuous voltage pulse at branch point 91 and associated output terminal 81 will vary depending on the player's hand. Changes in response to movement. Vibrations in the player's hands produce similar vibrations in the amplitude of the continuous voltage pulse at terminal 81.

The signal that identifies the setting of the alarm/strange sound selection switch 27 is as follows:
generated in circuit 68 by a linear potentiometer 93 having a resistive element 94 coupled between associated input terminal 66 and chassis ground and shifted to three positions along the resistive element by depression or release of actuator button 97 There is an adjustment tap 96.

Tap 96 is connected to another detection circuit output terminal 81 by another amplifier circuit 92c similar to amplifier circuit 92a described above.
is combined with Thus, with each activation of potentiometer 93 by decoder 64, a voltage pulse appears at terminal 81 having one of three different magnitudes, determined by the harmonica player. The maximum voltage generated when switch 27 is in the standard position signals that the standard is to be played. A partial depression of the actuator 97 to an intermediate position signals a warning tone, and a full depression indicates that an anomalous tone is to be synthesized.

A pair of fixed voltage divider resistors 98 and 99 are coupled in series between the associated input terminal 66 and chassis ground to generate a signal instructing the setting of the function selection switch 24a. A standard quantity function selection switch 24a bridges one of the resistors 98 connected directly to terminal 66. Resistor 9
The branch point 101 between 8 and 99 is coupled to another output terminal 88 of the detection circuit 74 through a further amplifier circuit 92d of the type previously described.

Thus, a repetitive voltage pulse having a first amplitude appears at the associated one detection circuit output terminal 82 when the switch 24a is in the normally open state and indicates that the function controlled by the switch is required. do. Closure of switch 24a by the harmonica player causes a high voltage pulse to appear at terminal 81, indicating to the sound synthesizer that the function is to be realized.

Circuit 68 has been described in detail with respect to only one channel of strain gauge 21 and only one channel of function selection switch 24a. It is understood that the circuit details for each of the other strain gauges and other function selection switches are of similar construction.

Referring to FIGS. 2 and 5 together, a voltage pulse of a predetermined amplitude appears at the detection circuit output terminal 81 when there is no airflow in the harmonica passage 17, and the strain gauge 21 is in a non-life condition. be. Bending of the strain gauge in one direction 21a raises the pulse amplitude from its standard value by an amount that depends on the extent of the bend and thus the air flow rate.

Bending of the gauge 21 in the opposite direction 21b results in a reduction in pulse amplitude, depending on the magnitude of the bend. Standard pulse voltages generated under conditions of no air flow are interpreted by the signal utilization system as a request for an off or silence signal. An increase or decrease in voltage from any of the strain gauge channels 67 is interpreted as a request for synthesis of a particular musical note to which the channel responds in amplitude or volume by the amount the voltage increases or decreases. The fact that the pulse amplitude increases or decreases by one from the no-airflow value, depending on the direction of the airflow, indicates that the musical tone produced by blowing into the harmonica l' 1 and the musical tone produced by sucking or sucking in the harmonica Allows for provisions between.

The circuit described above causes instantaneous voltage pulses to appear sequentially on the 16 output terminals 81 of the detection circuit 74 in repetitive cycles, each pulse being as desired by the harmonica player at that moment for a particular musical note or for a particular control function. It is an analog signal that characterizes something.

These signals are used in a variety of ways to control sound synthesizers of known types.

For example, referring to FIG. 6, the analog signal from the detection circuit output terminal 81 is digitized and MIDI
The signal is transferred to one or more digital sound synthesizers 102 in the form of a signal interface lO:l, typically a computer or microprocessor-10.
Controlled by 4. The structure and operation of such sound generating devices 106 are well understood in the art and range from electronic keyboards sold for amateur use.
It is widely used in equipment ranging from complex and expensive installations for professional synthesis of music or other sound effects. Typically, such devices include a function selection switch 107 that allows the operator to add a chord, convert a tonic, substitute a warning or alteration, or select a signal, among many other examples. Microprocessor-104 for modifying the original sounds produced by the musician in a variety of ways, including simulating sounds of instruments other than those actually produced.
condition to increase the amount of

The signal from the output 81 of the detection circuit 74 is transmitted to the receiving device 106 over 16 separate wires or radio channels, but this complexity is avoided by serializing the transmitted data over a single channel. To this end, multiplexer 108 sequentially reads the voltage from each terminal 81 and sends the corresponding signal voltage through a single signal channel lit to analog-to-digital converter 109 in serial form. Multiplexer 108 receives the same address signal as decoder 64;
Thus, synchronized with the activation of channel 67 by decoder 64, the sequence of signals is repeatedly read out.

The digital address codes for cycling through the multiplexer 108 and the repeating sequence for repeatedly enabling such components are generated by a type of circuit specifically designed for that purpose. For these purposes, a microprocessor-1 is coupled to a random access memory 113, a read-only memory 114 and an address launch 116.
It is convenient to use 12. Programming microprocessor 112 to read a series of stored digital addresses from memory 114 and generate circular enable signals for peripheral components 64, 108, 109, and 112 is a relatively primitive operation; Well understood in technology.

Analog-to-digital converter 109 converts each continuous signal voltage received on channel Ill into a multi-bit digital byte or word and converts the magnitude of the voltage and thus the instantaneous amplitude of the musical tone desired by the musician. identify. Converter 109 produces a 10-bit digital word in this example, providing a dynamic range of 60 dB, which exceeds that of an acoustic harmonica.

To transmit data to remote receiving device 106 on a single channel, the digital words produced by converter 109 are serialized prior to transmission to transmitter 33. A separate parallel-to-serial signal converter is used for this purpose, which is preferably performed by the microprocessor 112, and includes address bits with each word to identify the musical tone that the word characterizes. to transmit. Similarly, a separate serial-to-parallel converter is provided between the receiver 105 and the sound synthesizer 102 to re-parallelize successive signal bytes, which may also advantageously Receiver microprocessor-1
04.

The signal-generating harmonica is not limited to the generation of digital signals for transmission to the MIDI-equipped sound-equipped synthesizer 1 of the kind described above, and is adapted to control a wide variety of other sound-generating devices. For example, referring to FIG. 7, a harmonica may include any of a series of electrical oscillator circuits 117 configured to produce an audio frequency output in response to a control signal voltage and at an amplitude proportional to the magnitude of the control signal voltage. Used for selective activation. Each oscillator 117 is
It has different frequencies corresponding to the frequencies of different musical tones.

Each oscillator 117 is coupled to an acoustic speaker 118 through one of a series of buffer amplifiers 119. Thus, speaker 118 produces sound having an audible frequency that corresponds to the electrical frequency received from oscillator 117.

A modification of the harmonica circuit for this purpose requires battery 4
3 and on/off switch 28, positive and negative output terminals B
It includes connecting to a bipolar type DC power source 63a having + and B-. A pair of equal resistors 121 are connected in series to the B+ and B terminals, and the junction between the two resistors defines chassis ground for the circuit. Thus, the positive and negative voltages provided by power supply 63a have equal magnitude with respect to ground, but are of opposite polarity.

Each strain gauge 21 is connected in series to one of the groups of resistors 122 to the power supply terminals B+, B-, each of the resistors having a resistance equal to that of the strain gauge when in the relaxed or unbending state. has. Thus, the junction 123 between resistor 122 and strain gauge 21 is at ground potential when the gauge is in the unbending state, and there is no output signal. Because each strain gauge 21 and associated resistor 122 is actually a voltage divider, the increase in resistance of the gauge caused by bending is proportional to the amount of bending at branch point 122.
produces a positive voltage at Similarly, the decrease in strain gauge resistance caused by bending in the opposite direction is at branch point 1
A proportional negative voltage is generated at 23.

Each branch point 123 has a first diode 124 and a resistor 12
6 is connected to chassis ground through a second diode 127 and a resistor 128, the two diodes having opposite orientations to conduct positive and negative voltages, respectively. First diode 124 and resistor 126
The branch point 129 between is coupled through a DC amplifier 131 to a first control input of the oscillator 117, and the branch point 132 between the second diode 127 and the resistor 128 is
It is coupled to another oscillator 117 through a separate DC amplifier 133. Amplifier 133 is similar to oscillator 11 in this embodiment.
7 are all polarity inverting amplifiers in order to respond to control voltages of the same polarity. two strain gauges 21
Although the connections to are shown in FIG. 7, each of the other strain gauges in the harmonica is similarly connected to a separate pair of oscillators 117.

Thus blowing into a selected air passage of the harmonica activates a corresponding one of the oscillators 117 and produces a corresponding sound in the speaker 118. Air suction or suction through the same passage activates different oscillators 117 to produce different musical tones. DC amplifiers 131 and 133 are coupled to the same oscillator 117 if it is desired that the system generate the same tone in response to airflow in a particular harmonica passage without regard to flow direction.

Although the invention has been disclosed with respect to particular embodiments for purposes of illustration, many variations and modifications are possible and no limitations are intended to the invention other than as described in the claims. Not done.

The main features and aspects of the invention are as follows.

1. a body having a plurality of air passages, each corresponding to a different musical note; a power source; and a body that generates selected sequences of musical notes in response to the passage of the performer's breath through the selected passages; and means for causing the generating device to generate a sound characteristic signal passing through each of the passages to provide a sound characteristic signal identifying the note played and also identifying the amplitude at which the note is played. In response to the airflow
air flow sensing means for generating distinct electrical signals and for individually varying each of the signals in response to variations in air flow rate and direction in the passageway; An improvement comprising means for transferring the manufactured Rj.

2. the airflow sensing means includes a plurality of airflow sensors fixed to the body, each coupled to the power source and each exposed to the airflow within a separate one of the passageways; ,
Each of the airflow sensors has a separate output terminal at which a separate signal voltage is generated, and where the airflow sensing means is responsive to variations in airflow rate and direction in the passageway in which the sensor is located. The device according to item I above, wherein the output voltage at each of the sensor output terminals is independently varied.

3. The airflow sensing means includes a plurality of strain gauges, each of which is sensitive to a flexural elastic element exposed to the airflow in a separate one of the passageways and variations in the extent and direction of bending of the elastic element. In response, the device has a varying electrical resistance, and wherein the airflow sensing means generates the signal by detecting variations in the electrical resistance in each of the strain gauges. .

4. The airflow detection means includes a plurality of airflow sensors, each exposed to the airflow within a separate one of the air passages, and each configured to detect a separate one of the acoustic characteristic signals. an output conductor provided, and in which case the airflow sensing means cycles through sequential reading of the signal from successive output conductors, and the transmission means repeatedly reads out corresponding repetitions of the signal. The device according to item 1 above, wherein the sound characteristic signal is transmitted to the sound generating device in a sequence.

5. The air flow detection means generates the signal in the form of a variable DC voltage and further comprises an analog to digital signal converter coupled between the air flow detection means and the signal transmission means. Device.

6. The apparatus of claim 5, further comprising a parallel-to-serial signal converter coupled between the analog-to-digital converter and the transmission means.

7. The sound generating device is an electronic sound synthesizer of the type responsive to digital signal bytes in parallel form, the device further comprising: a receiver for receiving the signal from the sound generating device, the transmission means; 7. The apparatus of claim 6, comprising means and a serial-to-parallel signal converter coupled between said receiver means and said sound producing device.

8. further comprising means for digitizing the signal generated by the airflow detection means into a sequence of signal bytes, and address encoding means for appending additional signal bits to the signal bytes; Apparatus according to item 1 above, wherein the additional signal bit identifies the particular air passageway in which the particular signal was generated.

9. further comprising at least one manual control on the harmonica for selectively causing the sound generating device to make selected modifications in the generated music, the control being configured to perform auxiliary functions in response to the manual operation; Apparatus according to item 1 above, comprising means for generating a signal, and in which case the transmission means transmits the auxiliary function signal together with the sound characteristic signal to the sound generating device.

IO2 the airflow sensing means is a plurality of strain gauges, each of which is a flexural elastic element positioned to be bent by the airflow through a separate one of the air passages and changes in response to the bending; a plurality of strain gauges having an electrical resistance and a separate note signal output terminal; and a plurality of voltage dividing resistors, each in series with a separate one of the strain gauge resistors through the output terminal of the strain gauge. a plurality of voltage divider resistors coupled together; means for applying a predetermined voltage across each series voltage divider resistor and electrical resistance; and a plurality of note signal sense amplifiers, each with an associated electrical resistor. a plurality of note signal detection amplifiers having an input coupled to a separate one of the strain gauge signal output terminals for detecting changes in the voltage drop of the strain gauge; and sequentially transmitting an output signal from each of the amplifiers to the transmission means. and multiplexing means for repeated transmission.

11. further comprising address generating means for repeatedly generating a sequence of address codes, each identifying a distinct one of said air passages, and in this case applying a predetermined voltage across each series voltage divider resistor and electrical resistance. said means for applying said voltages successively in a sequence in response to said sequence of address codes, and in which case said multiplexing means, in response to said sequence of address codes, apply said voltages successively in sequence; 10. The apparatus of claim 10, wherein each of said amplifiers is sequentially coupled to said transmission means, said apparatus further comprising means for effecting transmission of said address code correspondingly with each said note signal.

12. The address generating means generates the address code in the form of a digital signal, and in this case the means for applying a predetermined voltage across each series voltage dividing resistor and electrical resistance is a digital signal receiving the address code. a decoder and having a plurality of outputs sequentially activated in response thereto;
and coupled in a separate series of electrical resistances with the series voltage divider resistor, the device further comprising an analog-to-digital signal converter for converting the note signal into digital form for simultaneous transmission by the address code. 12. The device according to claim 11, further comprising one means.

13. The device according to claim 12, wherein the address generating means and the means for producing the transmission of the corresponding analog symbol with each of the note signals are components of a digital microprocessor contained within the harmonica. Device.

14, the air passages extending in spaced parallel relationship within the body, and wherein the body further includes two pairs of parallel interior wall members between each air passage and an adjacent air passage; 1, wherein the wall members prevent air flow exchange between the passages, and the wall members of each pair of the pairs are spaced apart to define an empty air chamber between successive air passages. Device.

15. The apparatus of claim 1, further comprising means for establishing a flow restriction in each of the air passages, the flow restriction being of a progressively varying magnitude in successive air passages.

16. An electronic harmonica for controlling a tone synthesizer responsive to control signals for identifying musical tones to be synthesized, comprising: a harmonica body having a plurality of spaced air passages; and a plurality of electrical strain gauges in the body. , each is
a plurality of electrical strain gauges positioned to be bent by the air flow in a separate one of the air passages and having an electrical resistance that changes in response to the bending produced by air flow fluctuations in the air passage; and means for generating the control signal by detecting a change in the resistivity of each of the strain gauges.

17. An electronic harmonica for generating and transmitting digital control signals to a digital sound synthesizer, having a plurality of spaced air passages, each corresponding to a different musical note, and a harmonica body within the body. a signal transmission means for transmitting the digital control signal from the harmonica to the sound synthesizer; and a plurality of strain gauges fixed to the body, each of which is connected to a separate section of the air passageway. having a flexurally elastic element exposed to airflow within one of the elements and having an electrical resistance that changes in response to bending of the element, the electrical resistance being connected to a plurality of strains coupled to the voltage supply. a gauge; a detector means for detecting a change in the electrical resistance of each of the strain gauges and generating a plurality of analog electrical signals, each indicative of a change in the electrical resistance of a separate one of the strain gauges; and means for repeatedly generating a sequence of digitally encoded addresses identifying successive said strain gauges; and an analog-to-digital signal converter and said detector in response to receiving said successive said digitally encoded addresses. means for reading out a repetitive sequence of said analog electrical signals from said means for reading out said repeated sequences of said analog electrical signals to produce corresponding sequences of digital signal bytes identifying amplitudes of different musical tones produced by said sound synthesizer; means for directing a sequence to the analog-to-digital signal converter; means for appending an address code bit to each of the signal bytes to identify the musical tone each byte characterizes; and the address code. and means for directing said sequence of signal bytes comprising bits to said transmission means.

18. In a signal-generating harmonica for operating a sound converting device, a rectangular body having a plurality of independent air passages formed in a parallel arrangement, each air passage having an opening at one end and an opening at the other end. a rectangular body having resistor means in the section; a plurality of air flow sensing means, one air flow sensing means located in the center of each independent air passage; and each of the air flow sensing means comprising: a plurality of airflow sensing means operative to generate signals proportional to variations in airflow velocity and airflow direction in the associated airflow passages; and each airflow sensing means operative to detect a signal generated by each airflow sensing means. circuit means coupled to the air flow detection means for transmitting the resulting output signal to a sound transducer, whereby blowing and inhaling by the performer in the air passage produces a performance sound from the transducer; A signal generating harmonica comprising means.

19. The signal generating harmonica as described in 18 above, wherein each air flow detection means is a strain gauge device.

20. The signal of claim 19, wherein each strain gage device includes a resistance circuit placed on a flexural elastic element in communication with an associated air passageway, the signal varying in electrical resistance proportional to the degree and direction of bending of the elastic element. Generated harmonica.

21. The circuit means includes an electric strobe means and an output for each air passageway to repeatedly detect the signal of each airflow detection means and generate a musical note in the sound transducer as the air passes through. 19. The signal generating harmonica of claim 18, wherein the signal generating harmonica generates an electrical signal representative of instantaneous air flow rate and direction in an associated air passageway operative to generate the signal.

[Brief explanation of the drawing]

FIG. 1 is an external perspective view of an electronic harmonica according to a preferred embodiment of the invention. FIG. 2 is a cross-sectional view of the harmonica of FIG. 1 taken along line 2--2. Figure 3 shows line 3 of Figure 2 further showing the internal structure of the instrument.
- Partial cross-section taken along 3. FIG. 4 is an exploded perspective view showing the main components of the harmonica shown in the preceding figure. FIG. 5 is a circuit diagram showing some electrical components of the preferred embodiment. FIG. 6 is a circuit diagram further illustrating the components of a circuit that enables coupling of a harmonica to a MIDI-equipped digital sound synthesizer. FIG. 7 is an electrical schematic diagram of another embodiment of the non-digital invention designed to control a simple acoustic acid system. 11...Electronic harmonica 16...Air hole 17...Air flow path 21...Strain gauge 24...Switch

Claims (1)

[Claims] 1. A main body having a plurality of air passages each corresponding to a different musical tone, a power source, and a main body having a plurality of air passages each corresponding to a different musical tone; and means for causing the electric operating sound generating device to generate a sequence of sounds to be played.
air for generating distinct electrical signals in response to airflow through each of the passageways and for individually varying each of the signals in response to variations in airflow velocity and direction in the passageways; An electronic harmonica comprising: flow sensing means; and means for sending each of the sound characteristic signals to the sound generating device. 2. An electronic harmonica for controlling a tone synthesizer that responds to control signals that identify musical tones to be synthesized, comprising: a harmonica body having a plurality of spaced air passages; and a plurality of electric strain gauges in the body. a plurality of electrical strain gauges, each positioned to be bent by the air flow in a separate one of the air passages, each having an electrical resistance that changes in response to the bending; and air flow variations in the air passage. and means for generating the control signal by detecting a change in the resistivity of each of the strain gauges generated by the electronic harmonica. 3. An electronic harmonica for generating and transmitting digital control signals to a digital sound synthesizer, comprising: a harmonica body having a plurality of spaced air passages, each corresponding to a different musical tone; a signal transmission means for transmitting the digital control signal from the harmonica to the sound synthesizer; and a plurality of strain gauges fixed to the body, each of which is connected to a separate section of the air passage. flexurally elastic elements exposed to the airflow within the tube, and each having an electrical resistance that changes in response to bending of the element, the electrical resistance being connected to a plurality of strain a gauge; a detector means for detecting a change in the electrical resistance of each of the strain gauges and generating a plurality of analog electrical signals, each indicative of a change in the electrical resistance of a separate one of the strain gauges; and means for repeatedly generating a sequence of digitally encoded addresses identifying successive strain gauges; an analog-to-digital signal converter; and in response to receiving successive digitally encoded addresses;
means for reading out a repetitive sequence of said analog electrical signals from said detector means, said analog signals so as to produce corresponding sequences of digital signal bytes identifying amplitudes of different musical tones produced by said sound synthesizer; means for directing the resulting sequence of signals to the analog-to-digital signal converter; means for appending an address code bit to each of the signal bytes to identify the musical note each byte characterizes; and and means for directing said sequence of signal bytes including a sign bit to said transmission means. 4. In a signal generating harmonica for operating a sound converting device, it is a rectangular body having a plurality of independent air passages formed in parallel arrangement, each air passage having an opening at one end and an opening at the other end. a rectangular body having resistor means in the section; a plurality of air flow sensing means, one air flow sensing means located in the center of each independent air passage; and each of the air flow sensing means comprising: a plurality of airflow sensing means operative to generate signals proportional to variations in airflow velocity and airflow direction in the associated airflow passages; and each airflow sensing means operative to detect a signal generated by each airflow sensing means. circuit means coupled to the air flow detection means for transmitting the resulting output signal to a sound transducer, whereby blowing and inhaling by the performer in the air passage produces a performance sound from the transducer; A signal generating harmonica comprising means.