CA2011568A1 - Electronic harmonica for controlling sound synthesizers - Google Patents
Electronic harmonica for controlling sound synthesizersInfo
- Publication number
- CA2011568A1 CA2011568A1 CA 2011568 CA2011568A CA2011568A1 CA 2011568 A1 CA2011568 A1 CA 2011568A1 CA 2011568 CA2011568 CA 2011568 CA 2011568 A CA2011568 A CA 2011568A CA 2011568 A1 CA2011568 A1 CA 2011568A1
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- air flow
- signal
- harmonica
- air
- signals
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Abstract
ELECTRONIC HARMONICA FOR CONTROLLING SOUND SYNTHESIZERS
Abstract of the Disclosure A reedless harmonica generates control signals for a sound synthesizer which may, if desired, be situated away from the harmonica. The harmonica body has multiple air passages, each generating different musical notes through a plurality of air flow sensors which initiate electrical sig-nals which identify each note being played and indicate changes in the amplitude of the note through transducers.
In the preferred embodiment, the sensors are strain gages and circuits are provided for sequentially detecting the electrical resistivity of each gage in a repetitive scanning cycle to produce repetitive sequences of digitally coded signals. Signals produced by the harmonica can be used to control MIDI equipped sound synthesizers or for controlling other forms of electrically operated sound generating equip-ment.
Abstract of the Disclosure A reedless harmonica generates control signals for a sound synthesizer which may, if desired, be situated away from the harmonica. The harmonica body has multiple air passages, each generating different musical notes through a plurality of air flow sensors which initiate electrical sig-nals which identify each note being played and indicate changes in the amplitude of the note through transducers.
In the preferred embodiment, the sensors are strain gages and circuits are provided for sequentially detecting the electrical resistivity of each gage in a repetitive scanning cycle to produce repetitive sequences of digitally coded signals. Signals produced by the harmonica can be used to control MIDI equipped sound synthesizers or for controlling other forms of electrically operated sound generating equip-ment.
Description
Technical Field This inven~ion relat~s to musical instruments and more part.icularly to an electronic harmonica which generates electrical signals ~or controlling elec~ronic sound syn-thesizing devices.
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Backqround of the Inv2ntion The variety of sounds and range of amplitudes which can be produced with a traditional musical instrument are circumscri~ed by its design and by the physical limita-tions of the musician. Most conventional harmonicas, -for example, are tuned to play a very limited range of full tones and cannot produce sharp or flat half tones. An ex-perienced player can Nbend~ the notes to approximate half 1~ tones, but the result is less ~han desirable. The volume or amplitude of the tones produced ~y a conventional harmonica is also limited by the lung capacity of the musician.
Mechanically modified harmonicas have been designed to enable generation of half tones, as well as full tones. U.S. Patent 2,565,100, issuad August 21, 1951 to J.
R. Tate, discloses one example. Such instruments typically require the player learn new lip and hand movements that di~fer substantially from conventional techniques for play-ing a harmonica. These prior art instruments are also in-capable of providing for other embellishments that would be desirable, such as adding chords or ~ctave notes or changing frequencies, key, scale tempo or the like.
Prior e~orts to increase ths ran~e of sound in-tensitles obtainable from a harmonica have included instal-lation of a microphone on the harmonica which is ~oupled to a loudspeaker through an electrical amplifier, as ex-empli~ied by the above ldenti~ied U.S. Patent 2,565,100.
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Backqround of the Inv2ntion The variety of sounds and range of amplitudes which can be produced with a traditional musical instrument are circumscri~ed by its design and by the physical limita-tions of the musician. Most conventional harmonicas, -for example, are tuned to play a very limited range of full tones and cannot produce sharp or flat half tones. An ex-perienced player can Nbend~ the notes to approximate half 1~ tones, but the result is less ~han desirable. The volume or amplitude of the tones produced ~y a conventional harmonica is also limited by the lung capacity of the musician.
Mechanically modified harmonicas have been designed to enable generation of half tones, as well as full tones. U.S. Patent 2,565,100, issuad August 21, 1951 to J.
R. Tate, discloses one example. Such instruments typically require the player learn new lip and hand movements that di~fer substantially from conventional techniques for play-ing a harmonica. These prior art instruments are also in-capable of providing for other embellishments that would be desirable, such as adding chords or ~ctave notes or changing frequencies, key, scale tempo or the like.
Prior e~orts to increase ths ran~e of sound in-tensitles obtainable from a harmonica have included instal-lation of a microphone on the harmonica which is ~oupled to a loudspeaker through an electrical amplifier, as ex-empli~ied by the above ldenti~ied U.S. Patent 2,565,100.
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This results in the production of the music at the harmonica ; itself accompanied by a repr~duction of the music at the ,~, ., ,~ loudspeaker location. Fee~back effects, in such an arrange-~` ment, can disturb the musical performance. Such a system ; 5 also does not enable any embellishments of the musie ~! produced by the harmonica, other than volume amplification.
Recent deveLopments in electronie sound syn-the~ r~ have overcome th~ limitations imposed by the . . , desigll o~ tr~ditional musieal instruments and by the physi-~' 10 cal eapabilities of the musician. Such systems, in the most ~, advaneed forms, are typically controlled by a digital micxoprocessor be actuated with a keyboard or other input deviee, to produce virtually any audible tone and to provide any of a great variety of embellishments.
;, A harmonica construction eapable o~ eontrolling il 15 sueh synthesizers signi~icantly enhanees the range o~ musi-~'l eal options available to har~onica players. Preferably sueh an infitrument should have the ~eel of the traditional in-strument and not require any substantial alteration of the ~ eonventional teehniques ~or playing a harmoniea.
I,~ 20 Prior efforts to dispense with the reeds in the ' eonventional harmoniea and to substitute elee~rieal elements for eontrolling an eleetrieal sound produeing d~vic~ hav~
not extended the eapabilities 9f the eonventional instxu-ments~
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This results in the production of the music at the harmonica ; itself accompanied by a repr~duction of the music at the ,~, ., ,~ loudspeaker location. Fee~back effects, in such an arrange-~` ment, can disturb the musical performance. Such a system ; 5 also does not enable any embellishments of the musie ~! produced by the harmonica, other than volume amplification.
Recent deveLopments in electronie sound syn-the~ r~ have overcome th~ limitations imposed by the . . , desigll o~ tr~ditional musieal instruments and by the physi-~' 10 cal eapabilities of the musician. Such systems, in the most ~, advaneed forms, are typically controlled by a digital micxoprocessor be actuated with a keyboard or other input deviee, to produce virtually any audible tone and to provide any of a great variety of embellishments.
;, A harmonica construction eapable o~ eontrolling il 15 sueh synthesizers signi~icantly enhanees the range o~ musi-~'l eal options available to har~onica players. Preferably sueh an infitrument should have the ~eel of the traditional in-strument and not require any substantial alteration of the ~ eonventional teehniques ~or playing a harmoniea.
I,~ 20 Prior efforts to dispense with the reeds in the ' eonventional harmoniea and to substitute elee~rieal elements for eontrolling an eleetrieal sound produeing d~vic~ hav~
not extended the eapabilities 9f the eonventional instxu-ments~
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u.S. Patent 2,455,032, issued Nove~ber 30, 1948 to A. 0. Williams, describes a construction in which the reeds are replaced with pressura~ensikive switches, each o~ which can be operated by blowing into the harmonica and each o~
which causes a tone generator to produce a different one o~
a series of predeterminecl audio frequencies. The switches are on-of~ d~vices which cannot detect variations in the amplitude of notes that a musician generates.
U.S. Patent 3,516,320, issued ~une 23, 1970 to C.
A. Hillairet et al., also teaches the use of a series of air flow actuated switches to d~tect air flow in any of the pas-sages o~ a harmonica. Actuation of any of the switches changes the output frequency of an electrical oscillator, which is coupled to an audio speaker ~hrough an ampli~ier, to produce the musical note which corresponds to the par-ticular air passage. The circuit is an improvement of the Williams device in that an air velocity detector modulates the amplifier gain to vary the volume of the generated sound in response to variations in the flow rate of the player's breath. Additional controls enable the player to shift oc-taves and to lntroduce effects such as tremolo an~ produc-- tion of semi-tones.
However, the apparatus o~ U.S~ Patent 3,516,320 does not qenerate separate ele trical signals ~or each air passage that are independent-of each other and which encode both activation o~ the passage by the musician and also the desired amplitude of the no~e. The note sensing switches ~ 4 -' .
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are interlinked at the single oscillator which cannot respond accurately to simultaneous actuation of more than one such switch. The separ~te amplitude detecting means is a single detector which jointly monitors all air passages.
These characteristics do not pxovide the necessary ver-satility for controlling a saund synthesizer.
A further characteristic of prior electronic har-monicas is undesirable mechanical complexity and fragility in the air flow sensing mechanisms. This makes such instru-ments costly and prone to malfunc~ion from the e~fects of saliva, dust, impacts or the liXe.
The present invention is directed to overcoming one or more of the problems discussed above.
Summary of the Invention In one aspect, the present invention provides an electronic harmonica hav.ing a body with a plurality of air passages each corresponding to a difPerent musical note, an electrical power source and means for enabling an electri-cally operated sound producing device to produce selected sequences of the musical note signals in response to passage of the player's breath through selected passages. The har-monica includes air flow sensing means for produci~g separate electrical signals in respons~ ~o air ~low through each passage and for individually varying each of the sig-nals in response to variations of air ~low rate and direc-tion in the passage. This provides not characterizing sig-. .
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: '`.. .. . ; ' ' : , nals which identi~y notes ~ b played and also identi~y the amplitude at which the note is to be played. The harmonica further includes means fo~`transmitting each of the note characteri~ing signals to the sound producing transducer.
In another aspect of the pr~sent invention, an ~, .
electronic harmonica for controlling a sound synthesizing device that responds to control signals identifying musical notes includes a body having a plurality of spaced apart air passages and a plurality of electrical strain gages in the n body. Each of the strain gages is positioned to ba flexed by air flow in a separate one of the passages. The electri-cal re istivity of each gage changes in response to such flexing. Means are provided for producing the control sig-nals by dPtec~ing air flow induced changes of the resis-~, tivity of each of the strain gages.
In still another aspect, the invention provides an electronic harmonica for generating and transmitting digital control signals to a digital sound synthesizer. The har-monica body has a plurality of spaced apaxt air passages each corresponding to a different musical note and further ! components include a direct current electrical voltag~
supply and mPans for transmitting the digital control 5ig-nals from the harmonica to the soun~ synthesiæer. A
plurality of strain gages are secured to the body and each gag~ has a flexible resilient element exposed *o the air flow within a separate one of the air ~assages, Each strain -; gage has an electrical resistance which varies in response , , .. .. .
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to flexing of the element a~d which is connected across the voltage supply. Detector means sense changes of the resis-tance of each strain gage and produces a plurality o~ analog electrical signals, each of which indicates changes in the resistance of a separate one of the strain gages. The har-monica furkher includes means for repeti~ively generating a sequence of digitally coded addresses that identify succes-sive ones o~ the strain gages, an analog to digital con-verter, and means for reading out repetitive sequences of the analog signals from the detector means in response to receipt of successive digitally coded addresses. The resulting sequences of analog signals are directed to the analog to digital converter to produce corresponding se-quences of digital signal bytes that identify the amplitudes of musical notes which are to be produced by the sound syn-thesizer. Means are provided for adding address code bitsto each of the signal bytes to identify the musical note which each byte characterizes. The sequences of bytes, in-cluding the address code bits, are directed to the transmit-ting means.
~0 The invention provides a mechanically simple and damage resistant harmonica construction which greatly ex-pands the range o~ musical effects which c~n be created by the player of this novel instrument. The harmonica genera-.
tes electrical signals which continually identify air flow rate and direction in each air passage to enable an electronic sound syntbeslser to producF the desired notes at . . . : . :
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the desired amplitude and, if desired, to modify, augment and embellish the resulting music in wa~s that cannot }~e ac-c o m p 1 i s ~' h e d w i t h the conventional acoustic harmonica. In the preferred form, the invention produces the electrical sig-nals in a digital form which enables control of any of the variety of digital sound synthesizing systems or instruments that are equipped with the internationally standardized MIDI
(Music Instrument Digital Interface) ports.
Brief Description of the Drawinqs Fig. 1 is a perspective view of the exterior of an electronic harmonica in accordance with the preferred em-bodiment of the invention.
Fig. 2 is a cross-section view o~ the harmonica of ,; 15 Fig. 1 taken along line 2-2 thereof.
Fig. 3 is a partial section view talcen along line ;; 3 3 oî Fig. 2 rurther depicting the internal construction of the instrument.
;~ Fig. 4 is an exploded perspective view illustrat-ing the principal components of the harmonica of the preced-ing f igures ~
Fig. 5 is a circuit diagram depicting certain . .
electrical components of the preîerred embodimentO
Fig. 6 lS a circuit diagram showing further com ponents of the circuit which enable coupling of the har-monica to a MIDI equipped digital sound synthesizer.
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Fig. 7 is an electrical circuit diagram for ; another embodiment of the invention which is non-digital and designed for controlling a~ess complex sound producing sys-tem.
`; Detailed Description oE the Preferred Embodiment ~ R~erring initially to Fig. 1 of th,e drawings, an ,~ electronic harmonica 11 in accordance with this embodiment o~ the invention may, if desired, have an external con-; 10 ~iguration closely resembling that of a conventional instru-ment and may be of more or less the same size. Major struc-tural components include a flat body member 12 of rectan-gular outline and cover plates 13 secured against each side ' of the body member.
,~ Referring to Figs. 1 and 2 in conjunction, the forwar~ surface of body member 12 has rounded edges to define a mouthpiece 14 and is transpierced by a row of spaced apart wind'cell apertures 16 through which the musi-cal can blow or draw air in the conventional manne.r. Each such aperture 16 corresponds to a different not of the musi-cal scale as in an acoustical harmonica. ~his embodiment has twelve such apertures 16 to provide a chromatic har-monica although the instrument can also be constricted with other numbers of apertures. A diatonic harmonica, for ex-- ample, requires only ten apertures.
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With reference to Figs. 2 and 3, each wind c~l~
aperture 16 communicates with a separate one of a series of parallel air ~low passages 17 within body member 12, which passages extend through the back of the member. An im-mulator flow restriction 18 at the back of each such passage 17 has an opening 19 which is smaller than the passage and i5 sized to create the same degree of flow resistance that a player experiences in the corresponding passage o a conven-tional acoustic harmonica. This resistance progrPssively decreases at successive ones of the passages 17 and thus the opening~ 19 can be of progressively greater diameter at suc-cessive ones of the passages in the direction of the left or low note end o~ the instrument.
One of a series of electrical strain gages 21 ex~
tends into each passage 17 in order to sense air flow, direc.tion and also the rate of the flow as will be further discussed in connection with the electrical circuit of the harmonica 11. Strain gages 21 may be of ~he known form which have a flexible resilient backing 22 and a thin film-like electrical resistor 23 adhered to the backing. Thus, flexing of the backing tensions or compresses the resistor to cause a detectable change of resistanca. The strain t yages 21 of this particular example are of the form which are pretensioned while being adhered to the backing 22.
Consequently, flexing of the gage 21 in one direction as il-lustrated at 21a causes the electrical resistance to in-crease as a function of the degree o~ flexing and movemen~
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in the opposite direction, as illustrated at 21b, causes a progressive decrease in resistance. This enables sound processing equlpment whlch~,may be coupled to the harmonica ll to distinguish signals produced by blowing into ~he pas-sage 17 from signals caused by drawing air through same pas-sage. ~ir flow direction is sensed to provide two note sig-;~ ~als from each passage.
Reerring a~ain to Fig. 1, the manually operated controls 24 on the harmonica 11 o~ this particular embodi-ment include two push button switches 24a and 24b that are accessible at the central region of the top cover plate 13.
The switches 24 enable the player to signal th~ sound syn-thesizer 26 to select the various alterations which such systems are programmed to per~orm such as, for example, the introduction of chords or simulation o~ the sound of another , 15 musical instrument. Additional switches 24 may be provided to increase the number of such options available to the har-monica player of this novel instrument. Electrical connec-tions to such switches will be hereinafter described.
Another push button 27 extends from the right side ` 20 of harmonica 11 for selectively causing the generation of sharp or flat notes as will also be further discussPd. A
switch 2~ for turning the harmonica 11 on and off is situated at the back of body member 12 in this example.
The harmonica 11 is Xurther provide~ with trans-, 25 mitting means 29 for delivering signals to the remote sound ; synthesiz~r ~6. Such means 29 as depicted in Fig. 1 include .
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a signal output port of jack 31 located at the left side2o~ ~
body member 1~ into which a multi-conductor electrical cable 32 can be plugged to condu~ signals to the synthesizer 26.
Other modes of signal transmission can also be used such as fiber optic transmission of coded light signals. It is ad-vantageous in many cases, such as in stage performances, to dispense with any ~orm of cable 32. For this purpose, the harmonica 11 may contain a small low power radio transmitter 33 having an antenna wire 3~ which extends for a short dis-lo tance along the left side and back of the exterior of body member 12~
Fig. 4 depicts a compact, and acceptable detailed construction for the novel harmonica 11, although it should be recognized that the components can have other configura-tions and also may ~e differently arranged.
Body member 12 in this embodiment is a rectangular frame having a series of spaced apart partitions 36 extend-ing from front to back to define the side walls of the air passages 17. Preferably, a pair o~ such partitions 36 are disposed between each passage 17 and the ad]acent passages, which pair o~ partitions axe slightly spaced apart as better seen in Fig. 3. This provides a thin cushioning dead air space 37 between successive passages 17 which prevents cross-talk. Any flexing o~ the partition 36 at one passage 17 that may occur from changing air flow is not transferred`~
to the adjoining passages and thus doeæ not result in spurious signals in adjoining passages.
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Xeferring again to Fig. 4, most of the components of the electrical circuit of the harmonica 11 are attached to or formed in a thin fl~t rectangular circuit board 38 which seats in a rectangular shelf 39 at the top of body 5member 12. Most such components, other than function switches 24a, 24b, output port 31 and a vibrato/tremolo con-trol 41, are not depicted in Fig. 4, as the scale of the drawing does not permit such depiction and such components will be hereinafter described with reference to circuit 10diagrams.
Another thin flat board ~2 similarly seats against the underside of body member 12 and carries the sharp/flat switch 27 and a rechargeable electrical battery 43 at op-posite end locations where such components can be received in the body men~er at opposite ends of the series of parti-15tions 36. Battery 43 has projecting needle-like terminals 44 that penetrate into positive and negative power supply terminal regions 46 of the circuit board 38 upon assembly of the components. Body member 12 has an opening 47 located to provide access to the recharging terminal port 48 for bat-20tery 43~
The strain gages 21 in this embodiment are linked together at the top by a continuous strip of material 49 which may b~ integral with the previously described backing material 22 of the individual gagesO In the assembled har-25monica 11, the gages 21 extend down into separate ones o~
the air passages 17 through a row of aligned slots 51 in the .
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circuit board 38. Referring again to Fig. 2, the strip por-tion 49 of the strain gage 21 assembly is clamped between two parallel insulative li~ear members 52 that are secured to the top of circuit board 38. Needle-like contacts 53 are penetra~ed through one such member 52 to provide for electrical connections between the strain gayes 21 and other circuit components.
Re~erring to Figs. 2 and 4 in conjunction, the im-mulator flow reskriction openin~s 19 in this example are formed in a slat-like member 54 which ~its into a slot 56 that extends along the back of body member 1~, successive ones of the openings being located to register with succes-sive ones of the air flow passages 17. Slat member 54 can be replaced with another one having different sized openings 19 if it is desired to adjust the resistance to blowing or drawing which the player experiences.
Referring again to Fig~ 4 in particular, insertion of the immulator slat 54 into slot 56 is followed by inser-tion of a small infrared light filter 57 into the end region of the slot. Filter 57 seats over an infrared light window 58 in body member 12 which ~aces the vibrato/tremolo control 41. One portion of control 41 is an infrared light source 41a directed at window 58 and another portion of the contrQl is an infrared detector 41b positioned to view the windowO
The player's hand is situated behind the window 58 and reflects infrared from source 41a back to detector 41b. By movement o~ tha hznd, the player =ay vary the amount of in-.
, frared light that is re~lected back to detector 41b and thereby vary the output signal of the detector. As will hereinafter be further descri~ed, this signal will cause the sound synthesizer to oscillate a sound ~requency and thereby cause a vibrato or ~rem~lo effect. The ~ilter 57 prevents distortion of the desired signals by keeping al~bient visible light awa~ ~rom detector 4lb.
Covers 13, which have a shallow dished shape, fit against the top and bottom of hody member 12 to enclose the internal components of the harmonica 11 and to define a hand grip. Covers 13 have a pair of shallow notches 59 at each end for, with reference to Fig. 1, receiving the ends of U-shaped spring tensioned clips 61 which secure the as-sembled components together. The components may also be held together by other fasteners such as screws or by adhesives if the instrument is not intended to be disas~
semble.
Referring now to Fig. 5, electrical components of the harmonica receive D.C. operating voltage fxom the posi-tive terminal B~ o~ a voltage xegulator 63 which also has another terminal 69 de~ining a common conductor or chassis ground. The battery 43 and on-off switch 2 ~ are connected across the voltage regulator 63 input terminals ~3t in series relationship vith each other.
The strain gages 21, the function control switches such as 24a, the sharp/flat switch 27 and the vi~rato/tremolo control 41 are each in a separa~e one o~
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sixteen signal channels 67 through a signal generating cir~
cuit 68. Channels 67 sequentially receive a momentary input , ' voltage from a digital ,~`ddress decoder 64 which will ;, hereinafter be further discussed. The sequence of momentary ;" 5 applications of B-t vol~age to the input terminals 66 of ,' ` channels 67 is continually repeated, while the instrumant is '',' in operation, preferably at a high repetition rate or fre-quency which is 20 ~2 in this particular example. ~igh fre-quency scanning of the channels 67 produces higher quality ;~ 10 sound as air flcw changes are detected more quickly and in ,'` smaller increments than is possible at lower frequencies.
Each s.rain ~age 21, of which only a single one is ` depicted in Fig. 5, is connected between the input terminal ~ 66 of a separate channel 67 and chassis ground in series ,1 relationship with a fixed resistor 71. Thus each such gage 21 and its associated resistor 71 functions as a voltage ~, divider and the voltage at the junction 72 between the gage '' , and resistor, during successive energizations of the channel 67, varies in response to the changes of resistivity of the gage that are caused by variations in air flow ra~e through : !
~ 20 the corresponding one of the harmonica passages as previ-,,~,' ~` ously descxibed. The varying voltage pulses from each such `~``. circuit junction 72 are transmitted to a separate input ter-`,~ minal 73 of a signal sensing circuit 74.
Within the signal sensing circuit 7~, each input terminal 73 is connected to the nega~iv~ or inverting input of a separate one of a series of voltage amplifiers 76 :
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through an input resistor 77, the positi~e or noninvertiny input of the amplifier being connected to ground through another resistor 78~ A feedback resistor 79 fixes the gain of the amplifier 76 in the known mannèr.
Ou~put pulses ~rom ampli~ier 76 are transmitted to a separate one of a series of output terminals 81 of the sensing circuit 74 through one of a series of buffer ampli~iers 82~ In particular, the output of amplifier 76 is coupled to the noninverting input of buf~er amplifier 82 through a capacitor 83 which input is also connected to ground through a resistor ~4. The inverting input of the - bu~er amplifier 82 is connected to chassis ground through another resistor 86 and to the output o~ the amplifier through a feedback resistor 87. Thus, each ~uf~er amplifier 82 of the sending circuit 74 transmits a voltage pulse to the associated out-terminal 81 each time decoder 64 ener-gizes the associated signal channel 67, the amplitude of the pulse being indicative o~ the momentary rate of air flow thxough the corresponding one of the harmonica air passages at the time of the strobe.
To generate the vibrato/tremolo signal within the signal generating circuit 68, the in~rared lig~t detector 4lb is a photodiode connected between a decoder terminal 66 and chassis ground in series wi h a voltage droppi~g resis-tor 89. The junction 91 between photodiode d2tector 41b and resistor 89 is coupled to the associated separa~e one o~ th outpu~ terminals 81 in sensing circuit 7~ through an ,, ' : ' , ' amplifier circuit 92b which may bs similar to the circui~
92a described above wi~h refer~nce to the s~rain gage 21 signal ohannel. The inf~a~d light source 41a, which may be a light emitting diode, is connected between the same input terminal 66 and chassis ground.
Thus the diodes ~la and 41~ ara bokh momentarily energized each time that decoder 64 applies a momentary vol~age to the associated input terminal 66. The amount of in~rared light from diode 41a that is received by diode 41b is dependent on the harmonica player's hand movements in the manner previously described. The diode detector 41b and resistor 89 are in effect a voltage divider. Consequently, as the resistance of diode 4lb varies in response to varia-tions in the amount of infrared which it receives, the mag-nitude of successive voltage p~lses at junction 91 and at . . . .
~ 15 the associated output terminal 81 is varied in response to ; the player's hand movements. Oscillation o~ the player's hand causes a similar oscillation oP the amplitude of suc-cessive voltage pulses at the terminal 81.
Signals identiying the setting of the sharp/flat selector switch 27 are generated in circuit 68 by a linear potentiometer 93 having a resistive element 94 connected be-tween the associated input terminal 66 and chassis ground and having an adjustable tap 96 which is shiftable to any of three positions along the resistiYe element by depresslo~ or release of the actuator button 97.
~; - 18 -. ~. .'. , . ' . ' ' ' ' ' ' ': : ' Tap 96 is coupled to another of the sensing clr-cuit output terminals 81 by another amplifier circuit 92c similar to the previous~y,~escribed amplifier circuit 92a.
Thus, upon each energization of the potentiomater 93 by decoder 64, a voltage pulse appears at the terminal 81 that has one of three different magnitudes as determined by the harmonica player. ~he highest magnitude vol~age, produced when switch 27 is at its normal position, signals that natural notes are to be played. Partial depression of the actuator 97 to the intermediate position signals ~or sharp notes and full depression indicates that flat notes are to be synthesized.
In order to genera~e signals indicating the set-ting of function selector switch 24a, a pair of fixed volt-age divider resistors 98 and 99 are connected in series be-tween the associated input terminal 66 and chassis ground.
the normally open function selector switch 24a bridges the one of the resistors 98 that is directly connected to ter-minal 66. The junction 101 between resistors 98 and 99 is coupled to another output terminal 88 of sensing circuit 7~
through still another amplifier circuit 92d of the type pre-viously described.
Thus repetitive voltages pulses having a ~irst amplitude appear at the associated one of the sensing cir-cuit output terminals 81 when switch 24a is in the normal open condition and indicate hat the unction:aontrolled by the switch iR not wanted. Cl~sing of th~ ~witch 24a by the l9 _ ::
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harmonica player causes higher voltaga pulses to appear at - the terminal 81 to signal the sound synthesizer that the function is to be implemen~ed.
The circuit 68 has been described in detail with respect to only one of the s~rain gage 21 channels and only one o~ the function selector switch 2~a channels. It should be understood that the circuit detail for each of the other strain gages and th2 o~her ~unction selec~or switch may be of sin~ilar conPiguration.
It may be noted, with refer~nce jointly to Figs. 2 and 5, that voltage pulses of a predetermined amplitude will appear at sensing circuit output terminals 81 when there is no air flow in the harmonica passages 17 and tha strain gages 21 are in the unflexed state. Flexing of the strain gages 21 in one direction 21a causes the pulse amplitudes to rise from this normal value by an amount dependent on the ' degree of flexing and thus the rate of air flow. Flexin~ of ~, the gages 21 in the opposite direction 21b causes a lowering of pulse amplitudes to a degree dependent on the magnitude of the flexing. The normal pulse voltage that is produced under conditions of no air flow is in~erpreted by the signal utilizing system as calling for an off or no sound signal.
Increasing or dPcreasing voltage~ Prom any of the strain gage channels 67 are interpreted as calling ~or syntheslzing of the particular musical note to which that channel cor-~ 25 responds at an amplitude or volume dependen~ on the amount '` of the voltage increase or decrease. The fact that the .1 .
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pulse amplitudes may either increase or decrease from the no air flow value, depending on direction o~ air flow, enables definition be~ween notes ~oduced by blowing into the har-monica 11 and notes producing by drawing or sucking on the 5harmonica.
Th~ circuit described above causes momentary volt-age pulses to appear sequentially at the sixteen output ter-minals 81 of the sensing circuit 74 in a repetitive cycle, each pulse being an analog signal which characterizes what 10the harmonica player desires at that instant with respect to a particular musical note or with respect to a particular control function. These signals may be used in any of various way for controlling known forms of sound synthesiz-ing apparatus.
For example, with reference to Fig. 6, the analog 15signals from sensing circui~ output terminals 81 may be digitized and transmitted to one or more digital sound syn-thesizers 102 oE the type having a MIDI signal interface 103 and which are typically controlled by a computer or microprocessor 104. ~he construction and operation of such 20sound generating equipment 106 are well understood in the art and widely employed in apparatus ranging from electronic keyboards sold for amateur use to complex, costly ins~alla-tions for professional synthesizing of music or other acous-tical effects. Typically such apparatus incIudes a function 25selector console 107 by which an operator can condi~ion the microprocessor 104 to augment to modify the oriqinal notes 2 0 ~
produced by the musician in any of a variety of ways, ln-cluding, among many other ~xamples, addition of chords, con-version of musical key, substitution of sharp or flat notes or simulation of the sound of some instrument other than the one at which the signals actually originate.
The signals from the outputs 81 o~ sensing circuit 74 can be transmitted to the receiving e~uipment 106 over sixteen separate lines or radio channels but this complica-tion can be avoided by serializing the data for transmission by a single channel. For this purpose, a multiplexer 108 reads out the voltages from each term.inal 81 in sequence and `` delivers corresponding signal voltages to an analog to digi-tal signal converter 109 in serial form through a single signal channel 111. Multiplaxer 108 receives the same ad-dress signals as decoder 64 and thus repetitively reads out ".;~ 15 the sequence of signals in synchronism with the energizing , of the channels 67 by decoder 64.
`,, The repetitive sequence of digital address codes for cycling decoder 64 and multiplexer 108 and clock signals ` for repetitively enabling such components can be generated ;. 20 by circuits of the type specifically designed ~or the pur-pose but it is advantageous to use a microprocessor 112, coupled to a random access memory 113, read only memory 114 and address latch 116, for these purposes. Programming o~ a ~- microprocessor 112 to repetitlvely ~read out a~serLe of stored digital address~d ~rom memory 114 and to generate .
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cyclical enabling signals for peripheral components 64, 108, los and 112 is a relatively simple operation well understood in the art.
Analog to digital converter 109 converts each suc-cessive signal voltage received on channel 111 to a multibit digital byte or word that identifies the magnitud~ of the voltage and thus the momentary amplitude of the musical note that the h~rmonica player desires. Converter 109 produces ten bit digital words in this example in order to provide 60 dB of dynamic range which exceeds that of an acoustic har-monica.
To provide ~or transmission of the data to the remote receiving equipment 106 over a single channel, the digital words produced by converter 109 are serialized prior to delivery to the transmitter 33. While a separate paral-lel to ,serial signal converter can be used for the purpose, this is preferably done by the microprocessor 112 which also transmits the address bits with each such word to identify the note which the word characterizes. Similarly, a separate serial to parallel converter may be provided be-tween the received 105 and sound synthesizer 102 to reparal-lelize the successive signal bytes but this is more con-veniently done by the receiver microprocessor 104.
The signal generating harmonica is not limited to production of digital signals for transmission to a MIDI
e~uipped sound synthesizing device 106 of the above described kind and can be adapted to~control a variety of 2011~
other sound generating devices. For example, with reference to Fig. 7, the harmonica can be used to selectively actuate any of a series of electri~l oscillator circuits 117 of the type that gen~rate an audio fre~uency output in response to a control signal voltage and at an amplitude that is propor-tional to the magnitude of the control signal voltage. Each such oscillator 117 may have a di~ferent frequency cor-responding to the frequency of a di~ferent musical note.
i Each such oscillator 117 may be coupled to an audio speaker lo 118 through a separate one of a series of bu~fer amplifiers 119. Thus the speaker 118 produces sounds having audio fre-quencies corresponding to ~he electrical frequency received from any of the oscillators 117.
; Modifications of the harmonica circuits for this purpose include connecting the battery 43 and on-off switch 28 to a D.C. power supply 63a of the bipolar type which has ~..
both positive and negative output terminals B+ and B-. A
pair of equa`l resistances 121 are connected in series across ~ the B+ and B- terminals and the junction between the two ; resistances define the chassis ground for the circuit. Thus, ~ 20 the positive and negative voltages provided by the power .t~ .
` supply 63a have equal magnitudes relative to ground but are of opposite polarities.
Each strain gage 21 is connected across the power supply terminals B+, B- in series with one of a group of ; 25 resistors 122 each of which has a re istance equal to that ~; of the strain gage when it is in the relaxed o~ unflexed :; :
i - 24 -~ .
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, ' ' ., condition. Thus, the junctions 123 between the resistors ~, 122 and strain gages 21 are at ground potential when the gages are in the unflexe~ state and no output signal is ' present. As each strain gage 21 and the associated resistor ; 5 122 is in effect a voltage divider, an increase of the resistance of the gage caused by flexing results in a posi-tive voltage at junction 1~3 that is proportional to the amount oP ~lexing. Similarly, a ~ecrease of the strain gage ` ! resistance caused by flexing in the opposite direction produces a proportionate negative voltage at junction 123.
ach junction 123 is connected to chassis ground through a first diode 124 and resistor 126 and also through ~l~ a second diode 127 and resistor 128, the two diodes being oppositely oriented to conduct positive and negative volt-.
` ages respectively. The junction 129 between first diode 124 : 15 and resistor 126 is coupled to the control input of a first ~; o~ the oscillators 117 through a D.C.amplifier 131 and the ',~ junction 132 between second diode 127 and resistor 128 is `, coupled to another of the oscillators 117 through a separate D.C.amplifier 133. Amplifier 133 is a polarity inverting amplifier as the oscillators 117 of this embodiment all raspond to control voltages of the same polarity. While ~he - connections to only two of the strain qages 21 are depicted f in Fig. 7, each of the other s rain gages in the harmonlca is similarly connected to a separate pair o~ the oscillators 117.
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Thus blowing into any selected air passage of the harmonica actuates a corresponding one of the oscillators 117 resulting in generat~n of the corresponding musical note at speaker 11~. Sucking or drawing air through the same passage actuates a different oscillator 117 t.o produce a different musical note. If it is desired that the system produce the same musical note in response to air flow in a particular harmonica passage without regard to the direction of flow, the D.C. amplifiers 131 and 133 may be coupled to the same oscillator 117.
While the invention has been disclosed with respect to certain particular embodiments for purposes of example, many variations and modifications are possible and it is not intended to limit the invention except as de~ined in the following claims.
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u.S. Patent 2,455,032, issued Nove~ber 30, 1948 to A. 0. Williams, describes a construction in which the reeds are replaced with pressura~ensikive switches, each o~ which can be operated by blowing into the harmonica and each o~
which causes a tone generator to produce a different one o~
a series of predeterminecl audio frequencies. The switches are on-of~ d~vices which cannot detect variations in the amplitude of notes that a musician generates.
U.S. Patent 3,516,320, issued ~une 23, 1970 to C.
A. Hillairet et al., also teaches the use of a series of air flow actuated switches to d~tect air flow in any of the pas-sages o~ a harmonica. Actuation of any of the switches changes the output frequency of an electrical oscillator, which is coupled to an audio speaker ~hrough an ampli~ier, to produce the musical note which corresponds to the par-ticular air passage. The circuit is an improvement of the Williams device in that an air velocity detector modulates the amplifier gain to vary the volume of the generated sound in response to variations in the flow rate of the player's breath. Additional controls enable the player to shift oc-taves and to lntroduce effects such as tremolo an~ produc-- tion of semi-tones.
However, the apparatus o~ U.S~ Patent 3,516,320 does not qenerate separate ele trical signals ~or each air passage that are independent-of each other and which encode both activation o~ the passage by the musician and also the desired amplitude of the no~e. The note sensing switches ~ 4 -' .
2 0 ~
are interlinked at the single oscillator which cannot respond accurately to simultaneous actuation of more than one such switch. The separ~te amplitude detecting means is a single detector which jointly monitors all air passages.
These characteristics do not pxovide the necessary ver-satility for controlling a saund synthesizer.
A further characteristic of prior electronic har-monicas is undesirable mechanical complexity and fragility in the air flow sensing mechanisms. This makes such instru-ments costly and prone to malfunc~ion from the e~fects of saliva, dust, impacts or the liXe.
The present invention is directed to overcoming one or more of the problems discussed above.
Summary of the Invention In one aspect, the present invention provides an electronic harmonica hav.ing a body with a plurality of air passages each corresponding to a difPerent musical note, an electrical power source and means for enabling an electri-cally operated sound producing device to produce selected sequences of the musical note signals in response to passage of the player's breath through selected passages. The har-monica includes air flow sensing means for produci~g separate electrical signals in respons~ ~o air ~low through each passage and for individually varying each of the sig-nals in response to variations of air ~low rate and direc-tion in the passage. This provides not characterizing sig-. .
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: '`.. .. . ; ' ' : , nals which identi~y notes ~ b played and also identi~y the amplitude at which the note is to be played. The harmonica further includes means fo~`transmitting each of the note characteri~ing signals to the sound producing transducer.
In another aspect of the pr~sent invention, an ~, .
electronic harmonica for controlling a sound synthesizing device that responds to control signals identifying musical notes includes a body having a plurality of spaced apart air passages and a plurality of electrical strain gages in the n body. Each of the strain gages is positioned to ba flexed by air flow in a separate one of the passages. The electri-cal re istivity of each gage changes in response to such flexing. Means are provided for producing the control sig-nals by dPtec~ing air flow induced changes of the resis-~, tivity of each of the strain gages.
In still another aspect, the invention provides an electronic harmonica for generating and transmitting digital control signals to a digital sound synthesizer. The har-monica body has a plurality of spaced apaxt air passages each corresponding to a different musical note and further ! components include a direct current electrical voltag~
supply and mPans for transmitting the digital control 5ig-nals from the harmonica to the soun~ synthesiæer. A
plurality of strain gages are secured to the body and each gag~ has a flexible resilient element exposed *o the air flow within a separate one of the air ~assages, Each strain -; gage has an electrical resistance which varies in response , , .. .. .
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to flexing of the element a~d which is connected across the voltage supply. Detector means sense changes of the resis-tance of each strain gage and produces a plurality o~ analog electrical signals, each of which indicates changes in the resistance of a separate one of the strain gages. The har-monica furkher includes means for repeti~ively generating a sequence of digitally coded addresses that identify succes-sive ones o~ the strain gages, an analog to digital con-verter, and means for reading out repetitive sequences of the analog signals from the detector means in response to receipt of successive digitally coded addresses. The resulting sequences of analog signals are directed to the analog to digital converter to produce corresponding se-quences of digital signal bytes that identify the amplitudes of musical notes which are to be produced by the sound syn-thesizer. Means are provided for adding address code bitsto each of the signal bytes to identify the musical note which each byte characterizes. The sequences of bytes, in-cluding the address code bits, are directed to the transmit-ting means.
~0 The invention provides a mechanically simple and damage resistant harmonica construction which greatly ex-pands the range o~ musical effects which c~n be created by the player of this novel instrument. The harmonica genera-.
tes electrical signals which continually identify air flow rate and direction in each air passage to enable an electronic sound syntbeslser to producF the desired notes at . . . : . :
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the desired amplitude and, if desired, to modify, augment and embellish the resulting music in wa~s that cannot }~e ac-c o m p 1 i s ~' h e d w i t h the conventional acoustic harmonica. In the preferred form, the invention produces the electrical sig-nals in a digital form which enables control of any of the variety of digital sound synthesizing systems or instruments that are equipped with the internationally standardized MIDI
(Music Instrument Digital Interface) ports.
Brief Description of the Drawinqs Fig. 1 is a perspective view of the exterior of an electronic harmonica in accordance with the preferred em-bodiment of the invention.
Fig. 2 is a cross-section view o~ the harmonica of ,; 15 Fig. 1 taken along line 2-2 thereof.
Fig. 3 is a partial section view talcen along line ;; 3 3 oî Fig. 2 rurther depicting the internal construction of the instrument.
;~ Fig. 4 is an exploded perspective view illustrat-ing the principal components of the harmonica of the preced-ing f igures ~
Fig. 5 is a circuit diagram depicting certain . .
electrical components of the preîerred embodimentO
Fig. 6 lS a circuit diagram showing further com ponents of the circuit which enable coupling of the har-monica to a MIDI equipped digital sound synthesizer.
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Fig. 7 is an electrical circuit diagram for ; another embodiment of the invention which is non-digital and designed for controlling a~ess complex sound producing sys-tem.
`; Detailed Description oE the Preferred Embodiment ~ R~erring initially to Fig. 1 of th,e drawings, an ,~ electronic harmonica 11 in accordance with this embodiment o~ the invention may, if desired, have an external con-; 10 ~iguration closely resembling that of a conventional instru-ment and may be of more or less the same size. Major struc-tural components include a flat body member 12 of rectan-gular outline and cover plates 13 secured against each side ' of the body member.
,~ Referring to Figs. 1 and 2 in conjunction, the forwar~ surface of body member 12 has rounded edges to define a mouthpiece 14 and is transpierced by a row of spaced apart wind'cell apertures 16 through which the musi-cal can blow or draw air in the conventional manne.r. Each such aperture 16 corresponds to a different not of the musi-cal scale as in an acoustical harmonica. ~his embodiment has twelve such apertures 16 to provide a chromatic har-monica although the instrument can also be constricted with other numbers of apertures. A diatonic harmonica, for ex-- ample, requires only ten apertures.
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With reference to Figs. 2 and 3, each wind c~l~
aperture 16 communicates with a separate one of a series of parallel air ~low passages 17 within body member 12, which passages extend through the back of the member. An im-mulator flow restriction 18 at the back of each such passage 17 has an opening 19 which is smaller than the passage and i5 sized to create the same degree of flow resistance that a player experiences in the corresponding passage o a conven-tional acoustic harmonica. This resistance progrPssively decreases at successive ones of the passages 17 and thus the opening~ 19 can be of progressively greater diameter at suc-cessive ones of the passages in the direction of the left or low note end o~ the instrument.
One of a series of electrical strain gages 21 ex~
tends into each passage 17 in order to sense air flow, direc.tion and also the rate of the flow as will be further discussed in connection with the electrical circuit of the harmonica 11. Strain gages 21 may be of ~he known form which have a flexible resilient backing 22 and a thin film-like electrical resistor 23 adhered to the backing. Thus, flexing of the backing tensions or compresses the resistor to cause a detectable change of resistanca. The strain t yages 21 of this particular example are of the form which are pretensioned while being adhered to the backing 22.
Consequently, flexing of the gage 21 in one direction as il-lustrated at 21a causes the electrical resistance to in-crease as a function of the degree o~ flexing and movemen~
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in the opposite direction, as illustrated at 21b, causes a progressive decrease in resistance. This enables sound processing equlpment whlch~,may be coupled to the harmonica ll to distinguish signals produced by blowing into ~he pas-sage 17 from signals caused by drawing air through same pas-sage. ~ir flow direction is sensed to provide two note sig-;~ ~als from each passage.
Reerring a~ain to Fig. 1, the manually operated controls 24 on the harmonica 11 o~ this particular embodi-ment include two push button switches 24a and 24b that are accessible at the central region of the top cover plate 13.
The switches 24 enable the player to signal th~ sound syn-thesizer 26 to select the various alterations which such systems are programmed to per~orm such as, for example, the introduction of chords or simulation o~ the sound of another , 15 musical instrument. Additional switches 24 may be provided to increase the number of such options available to the har-monica player of this novel instrument. Electrical connec-tions to such switches will be hereinafter described.
Another push button 27 extends from the right side ` 20 of harmonica 11 for selectively causing the generation of sharp or flat notes as will also be further discussPd. A
switch 2~ for turning the harmonica 11 on and off is situated at the back of body member 12 in this example.
The harmonica 11 is Xurther provide~ with trans-, 25 mitting means 29 for delivering signals to the remote sound ; synthesiz~r ~6. Such means 29 as depicted in Fig. 1 include .
.~ :
a signal output port of jack 31 located at the left side2o~ ~
body member 1~ into which a multi-conductor electrical cable 32 can be plugged to condu~ signals to the synthesizer 26.
Other modes of signal transmission can also be used such as fiber optic transmission of coded light signals. It is ad-vantageous in many cases, such as in stage performances, to dispense with any ~orm of cable 32. For this purpose, the harmonica 11 may contain a small low power radio transmitter 33 having an antenna wire 3~ which extends for a short dis-lo tance along the left side and back of the exterior of body member 12~
Fig. 4 depicts a compact, and acceptable detailed construction for the novel harmonica 11, although it should be recognized that the components can have other configura-tions and also may ~e differently arranged.
Body member 12 in this embodiment is a rectangular frame having a series of spaced apart partitions 36 extend-ing from front to back to define the side walls of the air passages 17. Preferably, a pair o~ such partitions 36 are disposed between each passage 17 and the ad]acent passages, which pair o~ partitions axe slightly spaced apart as better seen in Fig. 3. This provides a thin cushioning dead air space 37 between successive passages 17 which prevents cross-talk. Any flexing o~ the partition 36 at one passage 17 that may occur from changing air flow is not transferred`~
to the adjoining passages and thus doeæ not result in spurious signals in adjoining passages.
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Xeferring again to Fig. 4, most of the components of the electrical circuit of the harmonica 11 are attached to or formed in a thin fl~t rectangular circuit board 38 which seats in a rectangular shelf 39 at the top of body 5member 12. Most such components, other than function switches 24a, 24b, output port 31 and a vibrato/tremolo con-trol 41, are not depicted in Fig. 4, as the scale of the drawing does not permit such depiction and such components will be hereinafter described with reference to circuit 10diagrams.
Another thin flat board ~2 similarly seats against the underside of body member 12 and carries the sharp/flat switch 27 and a rechargeable electrical battery 43 at op-posite end locations where such components can be received in the body men~er at opposite ends of the series of parti-15tions 36. Battery 43 has projecting needle-like terminals 44 that penetrate into positive and negative power supply terminal regions 46 of the circuit board 38 upon assembly of the components. Body member 12 has an opening 47 located to provide access to the recharging terminal port 48 for bat-20tery 43~
The strain gages 21 in this embodiment are linked together at the top by a continuous strip of material 49 which may b~ integral with the previously described backing material 22 of the individual gagesO In the assembled har-25monica 11, the gages 21 extend down into separate ones o~
the air passages 17 through a row of aligned slots 51 in the .
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circuit board 38. Referring again to Fig. 2, the strip por-tion 49 of the strain gage 21 assembly is clamped between two parallel insulative li~ear members 52 that are secured to the top of circuit board 38. Needle-like contacts 53 are penetra~ed through one such member 52 to provide for electrical connections between the strain gayes 21 and other circuit components.
Re~erring to Figs. 2 and 4 in conjunction, the im-mulator flow reskriction openin~s 19 in this example are formed in a slat-like member 54 which ~its into a slot 56 that extends along the back of body member 1~, successive ones of the openings being located to register with succes-sive ones of the air flow passages 17. Slat member 54 can be replaced with another one having different sized openings 19 if it is desired to adjust the resistance to blowing or drawing which the player experiences.
Referring again to Fig~ 4 in particular, insertion of the immulator slat 54 into slot 56 is followed by inser-tion of a small infrared light filter 57 into the end region of the slot. Filter 57 seats over an infrared light window 58 in body member 12 which ~aces the vibrato/tremolo control 41. One portion of control 41 is an infrared light source 41a directed at window 58 and another portion of the contrQl is an infrared detector 41b positioned to view the windowO
The player's hand is situated behind the window 58 and reflects infrared from source 41a back to detector 41b. By movement o~ tha hznd, the player =ay vary the amount of in-.
, frared light that is re~lected back to detector 41b and thereby vary the output signal of the detector. As will hereinafter be further descri~ed, this signal will cause the sound synthesizer to oscillate a sound ~requency and thereby cause a vibrato or ~rem~lo effect. The ~ilter 57 prevents distortion of the desired signals by keeping al~bient visible light awa~ ~rom detector 4lb.
Covers 13, which have a shallow dished shape, fit against the top and bottom of hody member 12 to enclose the internal components of the harmonica 11 and to define a hand grip. Covers 13 have a pair of shallow notches 59 at each end for, with reference to Fig. 1, receiving the ends of U-shaped spring tensioned clips 61 which secure the as-sembled components together. The components may also be held together by other fasteners such as screws or by adhesives if the instrument is not intended to be disas~
semble.
Referring now to Fig. 5, electrical components of the harmonica receive D.C. operating voltage fxom the posi-tive terminal B~ o~ a voltage xegulator 63 which also has another terminal 69 de~ining a common conductor or chassis ground. The battery 43 and on-off switch 2 ~ are connected across the voltage regulator 63 input terminals ~3t in series relationship vith each other.
The strain gages 21, the function control switches such as 24a, the sharp/flat switch 27 and the vi~rato/tremolo control 41 are each in a separa~e one o~
.
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sixteen signal channels 67 through a signal generating cir~
cuit 68. Channels 67 sequentially receive a momentary input , ' voltage from a digital ,~`ddress decoder 64 which will ;, hereinafter be further discussed. The sequence of momentary ;" 5 applications of B-t vol~age to the input terminals 66 of ,' ` channels 67 is continually repeated, while the instrumant is '',' in operation, preferably at a high repetition rate or fre-quency which is 20 ~2 in this particular example. ~igh fre-quency scanning of the channels 67 produces higher quality ;~ 10 sound as air flcw changes are detected more quickly and in ,'` smaller increments than is possible at lower frequencies.
Each s.rain ~age 21, of which only a single one is ` depicted in Fig. 5, is connected between the input terminal ~ 66 of a separate channel 67 and chassis ground in series ,1 relationship with a fixed resistor 71. Thus each such gage 21 and its associated resistor 71 functions as a voltage ~, divider and the voltage at the junction 72 between the gage '' , and resistor, during successive energizations of the channel 67, varies in response to the changes of resistivity of the gage that are caused by variations in air flow ra~e through : !
~ 20 the corresponding one of the harmonica passages as previ-,,~,' ~` ously descxibed. The varying voltage pulses from each such `~``. circuit junction 72 are transmitted to a separate input ter-`,~ minal 73 of a signal sensing circuit 74.
Within the signal sensing circuit 7~, each input terminal 73 is connected to the nega~iv~ or inverting input of a separate one of a series of voltage amplifiers 76 :
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through an input resistor 77, the positi~e or noninvertiny input of the amplifier being connected to ground through another resistor 78~ A feedback resistor 79 fixes the gain of the amplifier 76 in the known mannèr.
Ou~put pulses ~rom ampli~ier 76 are transmitted to a separate one of a series of output terminals 81 of the sensing circuit 74 through one of a series of buffer ampli~iers 82~ In particular, the output of amplifier 76 is coupled to the noninverting input of buf~er amplifier 82 through a capacitor 83 which input is also connected to ground through a resistor ~4. The inverting input of the - bu~er amplifier 82 is connected to chassis ground through another resistor 86 and to the output o~ the amplifier through a feedback resistor 87. Thus, each ~uf~er amplifier 82 of the sending circuit 74 transmits a voltage pulse to the associated out-terminal 81 each time decoder 64 ener-gizes the associated signal channel 67, the amplitude of the pulse being indicative o~ the momentary rate of air flow thxough the corresponding one of the harmonica air passages at the time of the strobe.
To generate the vibrato/tremolo signal within the signal generating circuit 68, the in~rared lig~t detector 4lb is a photodiode connected between a decoder terminal 66 and chassis ground in series wi h a voltage droppi~g resis-tor 89. The junction 91 between photodiode d2tector 41b and resistor 89 is coupled to the associated separa~e one o~ th outpu~ terminals 81 in sensing circuit 7~ through an ,, ' : ' , ' amplifier circuit 92b which may bs similar to the circui~
92a described above wi~h refer~nce to the s~rain gage 21 signal ohannel. The inf~a~d light source 41a, which may be a light emitting diode, is connected between the same input terminal 66 and chassis ground.
Thus the diodes ~la and 41~ ara bokh momentarily energized each time that decoder 64 applies a momentary vol~age to the associated input terminal 66. The amount of in~rared light from diode 41a that is received by diode 41b is dependent on the harmonica player's hand movements in the manner previously described. The diode detector 41b and resistor 89 are in effect a voltage divider. Consequently, as the resistance of diode 4lb varies in response to varia-tions in the amount of infrared which it receives, the mag-nitude of successive voltage p~lses at junction 91 and at . . . .
~ 15 the associated output terminal 81 is varied in response to ; the player's hand movements. Oscillation o~ the player's hand causes a similar oscillation oP the amplitude of suc-cessive voltage pulses at the terminal 81.
Signals identiying the setting of the sharp/flat selector switch 27 are generated in circuit 68 by a linear potentiometer 93 having a resistive element 94 connected be-tween the associated input terminal 66 and chassis ground and having an adjustable tap 96 which is shiftable to any of three positions along the resistiYe element by depresslo~ or release of the actuator button 97.
~; - 18 -. ~. .'. , . ' . ' ' ' ' ' ' ': : ' Tap 96 is coupled to another of the sensing clr-cuit output terminals 81 by another amplifier circuit 92c similar to the previous~y,~escribed amplifier circuit 92a.
Thus, upon each energization of the potentiomater 93 by decoder 64, a voltage pulse appears at the terminal 81 that has one of three different magnitudes as determined by the harmonica player. ~he highest magnitude vol~age, produced when switch 27 is at its normal position, signals that natural notes are to be played. Partial depression of the actuator 97 to the intermediate position signals ~or sharp notes and full depression indicates that flat notes are to be synthesized.
In order to genera~e signals indicating the set-ting of function selector switch 24a, a pair of fixed volt-age divider resistors 98 and 99 are connected in series be-tween the associated input terminal 66 and chassis ground.
the normally open function selector switch 24a bridges the one of the resistors 98 that is directly connected to ter-minal 66. The junction 101 between resistors 98 and 99 is coupled to another output terminal 88 of sensing circuit 7~
through still another amplifier circuit 92d of the type pre-viously described.
Thus repetitive voltages pulses having a ~irst amplitude appear at the associated one of the sensing cir-cuit output terminals 81 when switch 24a is in the normal open condition and indicate hat the unction:aontrolled by the switch iR not wanted. Cl~sing of th~ ~witch 24a by the l9 _ ::
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harmonica player causes higher voltaga pulses to appear at - the terminal 81 to signal the sound synthesizer that the function is to be implemen~ed.
The circuit 68 has been described in detail with respect to only one of the s~rain gage 21 channels and only one o~ the function selector switch 2~a channels. It should be understood that the circuit detail for each of the other strain gages and th2 o~her ~unction selec~or switch may be of sin~ilar conPiguration.
It may be noted, with refer~nce jointly to Figs. 2 and 5, that voltage pulses of a predetermined amplitude will appear at sensing circuit output terminals 81 when there is no air flow in the harmonica passages 17 and tha strain gages 21 are in the unflexed state. Flexing of the strain gages 21 in one direction 21a causes the pulse amplitudes to rise from this normal value by an amount dependent on the ' degree of flexing and thus the rate of air flow. Flexin~ of ~, the gages 21 in the opposite direction 21b causes a lowering of pulse amplitudes to a degree dependent on the magnitude of the flexing. The normal pulse voltage that is produced under conditions of no air flow is in~erpreted by the signal utilizing system as calling for an off or no sound signal.
Increasing or dPcreasing voltage~ Prom any of the strain gage channels 67 are interpreted as calling ~or syntheslzing of the particular musical note to which that channel cor-~ 25 responds at an amplitude or volume dependen~ on the amount '` of the voltage increase or decrease. The fact that the .1 .
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pulse amplitudes may either increase or decrease from the no air flow value, depending on direction o~ air flow, enables definition be~ween notes ~oduced by blowing into the har-monica 11 and notes producing by drawing or sucking on the 5harmonica.
Th~ circuit described above causes momentary volt-age pulses to appear sequentially at the sixteen output ter-minals 81 of the sensing circuit 74 in a repetitive cycle, each pulse being an analog signal which characterizes what 10the harmonica player desires at that instant with respect to a particular musical note or with respect to a particular control function. These signals may be used in any of various way for controlling known forms of sound synthesiz-ing apparatus.
For example, with reference to Fig. 6, the analog 15signals from sensing circui~ output terminals 81 may be digitized and transmitted to one or more digital sound syn-thesizers 102 oE the type having a MIDI signal interface 103 and which are typically controlled by a computer or microprocessor 104. ~he construction and operation of such 20sound generating equipment 106 are well understood in the art and widely employed in apparatus ranging from electronic keyboards sold for amateur use to complex, costly ins~alla-tions for professional synthesizing of music or other acous-tical effects. Typically such apparatus incIudes a function 25selector console 107 by which an operator can condi~ion the microprocessor 104 to augment to modify the oriqinal notes 2 0 ~
produced by the musician in any of a variety of ways, ln-cluding, among many other ~xamples, addition of chords, con-version of musical key, substitution of sharp or flat notes or simulation of the sound of some instrument other than the one at which the signals actually originate.
The signals from the outputs 81 o~ sensing circuit 74 can be transmitted to the receiving e~uipment 106 over sixteen separate lines or radio channels but this complica-tion can be avoided by serializing the data for transmission by a single channel. For this purpose, a multiplexer 108 reads out the voltages from each term.inal 81 in sequence and `` delivers corresponding signal voltages to an analog to digi-tal signal converter 109 in serial form through a single signal channel 111. Multiplaxer 108 receives the same ad-dress signals as decoder 64 and thus repetitively reads out ".;~ 15 the sequence of signals in synchronism with the energizing , of the channels 67 by decoder 64.
`,, The repetitive sequence of digital address codes for cycling decoder 64 and multiplexer 108 and clock signals ` for repetitively enabling such components can be generated ;. 20 by circuits of the type specifically designed ~or the pur-pose but it is advantageous to use a microprocessor 112, coupled to a random access memory 113, read only memory 114 and address latch 116, for these purposes. Programming o~ a ~- microprocessor 112 to repetitlvely ~read out a~serLe of stored digital address~d ~rom memory 114 and to generate .
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cyclical enabling signals for peripheral components 64, 108, los and 112 is a relatively simple operation well understood in the art.
Analog to digital converter 109 converts each suc-cessive signal voltage received on channel 111 to a multibit digital byte or word that identifies the magnitud~ of the voltage and thus the momentary amplitude of the musical note that the h~rmonica player desires. Converter 109 produces ten bit digital words in this example in order to provide 60 dB of dynamic range which exceeds that of an acoustic har-monica.
To provide ~or transmission of the data to the remote receiving equipment 106 over a single channel, the digital words produced by converter 109 are serialized prior to delivery to the transmitter 33. While a separate paral-lel to ,serial signal converter can be used for the purpose, this is preferably done by the microprocessor 112 which also transmits the address bits with each such word to identify the note which the word characterizes. Similarly, a separate serial to parallel converter may be provided be-tween the received 105 and sound synthesizer 102 to reparal-lelize the successive signal bytes but this is more con-veniently done by the receiver microprocessor 104.
The signal generating harmonica is not limited to production of digital signals for transmission to a MIDI
e~uipped sound synthesizing device 106 of the above described kind and can be adapted to~control a variety of 2011~
other sound generating devices. For example, with reference to Fig. 7, the harmonica can be used to selectively actuate any of a series of electri~l oscillator circuits 117 of the type that gen~rate an audio fre~uency output in response to a control signal voltage and at an amplitude that is propor-tional to the magnitude of the control signal voltage. Each such oscillator 117 may have a di~ferent frequency cor-responding to the frequency of a di~ferent musical note.
i Each such oscillator 117 may be coupled to an audio speaker lo 118 through a separate one of a series of bu~fer amplifiers 119. Thus the speaker 118 produces sounds having audio fre-quencies corresponding to ~he electrical frequency received from any of the oscillators 117.
; Modifications of the harmonica circuits for this purpose include connecting the battery 43 and on-off switch 28 to a D.C. power supply 63a of the bipolar type which has ~..
both positive and negative output terminals B+ and B-. A
pair of equa`l resistances 121 are connected in series across ~ the B+ and B- terminals and the junction between the two ; resistances define the chassis ground for the circuit. Thus, ~ 20 the positive and negative voltages provided by the power .t~ .
` supply 63a have equal magnitudes relative to ground but are of opposite polarities.
Each strain gage 21 is connected across the power supply terminals B+, B- in series with one of a group of ; 25 resistors 122 each of which has a re istance equal to that ~; of the strain gage when it is in the relaxed o~ unflexed :; :
i - 24 -~ .
. ~ . .
.. ~ ...~.
.
!
, ' ' ., condition. Thus, the junctions 123 between the resistors ~, 122 and strain gages 21 are at ground potential when the gages are in the unflexe~ state and no output signal is ' present. As each strain gage 21 and the associated resistor ; 5 122 is in effect a voltage divider, an increase of the resistance of the gage caused by flexing results in a posi-tive voltage at junction 1~3 that is proportional to the amount oP ~lexing. Similarly, a ~ecrease of the strain gage ` ! resistance caused by flexing in the opposite direction produces a proportionate negative voltage at junction 123.
ach junction 123 is connected to chassis ground through a first diode 124 and resistor 126 and also through ~l~ a second diode 127 and resistor 128, the two diodes being oppositely oriented to conduct positive and negative volt-.
` ages respectively. The junction 129 between first diode 124 : 15 and resistor 126 is coupled to the control input of a first ~; o~ the oscillators 117 through a D.C.amplifier 131 and the ',~ junction 132 between second diode 127 and resistor 128 is `, coupled to another of the oscillators 117 through a separate D.C.amplifier 133. Amplifier 133 is a polarity inverting amplifier as the oscillators 117 of this embodiment all raspond to control voltages of the same polarity. While ~he - connections to only two of the strain qages 21 are depicted f in Fig. 7, each of the other s rain gages in the harmonlca is similarly connected to a separate pair o~ the oscillators 117.
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. ~
Thus blowing into any selected air passage of the harmonica actuates a corresponding one of the oscillators 117 resulting in generat~n of the corresponding musical note at speaker 11~. Sucking or drawing air through the same passage actuates a different oscillator 117 t.o produce a different musical note. If it is desired that the system produce the same musical note in response to air flow in a particular harmonica passage without regard to the direction of flow, the D.C. amplifiers 131 and 133 may be coupled to the same oscillator 117.
While the invention has been disclosed with respect to certain particular embodiments for purposes of example, many variations and modifications are possible and it is not intended to limit the invention except as de~ined in the following claims.
.
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Claims (21)
1. In an electronic harmonica having a body with a plurality of air passages each corresponding to a dif-ferent musical note, an electrical power source, and means for enabling an electrically operated sound producing device to produce selected sequences of said musical notes in response to passage of the player's breath through selected ones of said passages, the improvement comprising:
air flow sensing means for producing separate electrical signals in response to air flow through each of said passages and for individually varying each of said sig-nals in response to variations of the rate of air flow and direction in the passage to provide note characterizing sig-nals which identify notes to be played and also identify the amplitude. at which the note is to be played, and means for transmitting each of said note characterizing signals to said sound producing device.
air flow sensing means for producing separate electrical signals in response to air flow through each of said passages and for individually varying each of said sig-nals in response to variations of the rate of air flow and direction in the passage to provide note characterizing sig-nals which identify notes to be played and also identify the amplitude. at which the note is to be played, and means for transmitting each of said note characterizing signals to said sound producing device.
2. The apparatus of claim 1 wherein said air flow sensing means includes a plurality of air flow sensors secured to said body, each being coupled to said power source and each being exposed to the air flow within a separate one of said passages, with each of said air flow sensors having a separate output terminal at which a separate signal voltage is produced and wherein said air flow sensing means independently varies the output voltage at each of said sensor output terminals in response to variations of air flow rate and direction in the passage at which the sensor is located.
3. The apparatus of claim 1 wherein said air flow sensing means includes a plurality of strain gages each having a flexible resilient element exposed to the air flow within a separate one of said passages and having an electrical resistance which varies in response to changes in the degree of and direction of flexing of the resilient ele-ment, and wherein said air flow sensing means produces said signals by detecting variations of said electrical resis-tance at each of said strain gages.
4. The apparatus of claim 1 wherein said air flow sensing means includes a plurality of air flow sensors each being exposed to the air flow within a separate one of said air passages and each having an output conductor for which a separate one of said note characterizing signals is provided, and wherein said air flow sensing means repeti-tively cycles through a sequential read-out of said signals from successive ones of said output conductors and said transmitting means transmits said note characterizing sig-nals to said sound producing device in corresponding repeti-tive sequences of said signals.
5. The apparatus of claim 1 wherein said air flow sensing means produces said signals in the form of variable D.C. voltages, further including an analog to digi-tal signal converter coupled between said air flow sensing means and said signal transmitting means.
6. The apparatus of claim 5 further including a parallel to serial signal converter coupled between said analog to digital converter and said transmitting means.
7. The apparatus of claim 6 wherein said sound producing device is an electronic sound synthesizer of the type which responds to digital signal bytes in parallel form, said apparatus further including said sound producing device, receiver means for receiving said signals from said transmitting means, and a serial to parallel signal conver-sion device coupled between said receiver means and said sound producing device.
8. The apparatus of claim 1 further including means for digitizing said signals that are produced by said air flow sensing means into sequences of signal bytes, and address encoding means for adding additional signal bits to said signal bytes which additional signal bits identify the particular air passage at which the particular signal originated.
9. The apparatus of claim 1 further including at least one manually operable control on said harmonica for selectively causing said sound producing device to perform a selected alteration in the music produced hereby, said con-trol having means for generating an auxiliary function sig-nal in response to manual operation thereof, and wherein said transmitting means transmits said auxiliary function signal to said sound producing device together with said note characterizing signals.
10. The apparatus of claim 1 wherein said air flow sensing means includes:
a plurality of strain gages each having a flexible resilient element positioned to be flexed by air flow through a separate one of said air passages and each having an electrical resistance which varies in response to said flexing, and each having a separate note signal output terminal, a plurality of voltage dividing resistors, each being connected in series with a separate one of said strain gage resistances through said output terminal of the strain gage, means for applying a predetermined voltage across each series connected voltage dividing resistor and electrical resistance, a plurality of note signal detector amplifiers each having an input connected to a separate one of said strain gage signal output terminals to detect changes in the voltage drop across the associated one of said electrical resistances, and multiplexing means for sequentially and repetitively transmitting an output signal from each of said amplifiers to said transmitting means.
a plurality of strain gages each having a flexible resilient element positioned to be flexed by air flow through a separate one of said air passages and each having an electrical resistance which varies in response to said flexing, and each having a separate note signal output terminal, a plurality of voltage dividing resistors, each being connected in series with a separate one of said strain gage resistances through said output terminal of the strain gage, means for applying a predetermined voltage across each series connected voltage dividing resistor and electrical resistance, a plurality of note signal detector amplifiers each having an input connected to a separate one of said strain gage signal output terminals to detect changes in the voltage drop across the associated one of said electrical resistances, and multiplexing means for sequentially and repetitively transmitting an output signal from each of said amplifiers to said transmitting means.
11. The apparatus of claim 10 further including address generating means for repetitively generating a se-quence of address codes each of which identifies a separate one of said air passages and wherein said means for applying a predetermined voltage across each series connected voltage dividing resistor and electrical resistance applies said voltage to successive ones thereof in sequence in response to said sequence of address codes and wherein said multi-plexing means sequentially couples each of said amplifiers to said transmitting means in corresponding response to said sequence of address codes, said apparatus further including means for causing transmission of the corresponding one of said address codes together with each of said note signals.
12. The apparatus of claim 11 wherein said ad-dress generating means generates said address codes in digi-tal signal form and wherein said means for applying a predetermined voltage across each series connected voltage dividing resistor and electrical resistance includes a digi-tal decoder receiving said address codes and having a plurality of outputs which are sequentially activated in response thereto and which are connected to separate succes-sive ones of said series connected voltage dividing resis-tors and electrical resistances, said apparatus further in-cluding analog to digital signal converter means for con-verting said note signals to digital form for joint trans-mission with said address codes.
13. The apparatus of claim 12 wherein said ad-dress generating means and said means for causing transmis-sion of the corresponding one of said address codes together with each of said note signals are components of a digital microprocessor contained within said harmonica.
14. The apparatus of claim 1 wherein said air passages extend in spaced apart parallel relationship within said body and wherein said body further includes a pair of parallel internal wall members between each air passage and the adjacent air passage which wall members block air flow exchange between passages, the wall members of each of said pairs being spaced apart to define dead air chambers between successive ones of said air passages.
15. The apparatus of claim 1 further including means for establishing a flow restriction in each of said air passages which flow restrictions are of progressively changing size in successive ones of said air passages.
16. An electronic harmonica for controlling a sound synthesizing device that responds to control signals identifying musical notes which are to by synthesized, com-prising:
a harmonica body having a plurality of spaced apart air passages, a plurality of electrical strain gages in said body, each being positioned to be flexed by air flow in a separate one of said air passages and each having an electrical resistivity which changes in response to said flexing, and means for producing said control signals by detecting changes of said resistivity of each of said strain gages that are produced by air flow variations in said air passages.
a harmonica body having a plurality of spaced apart air passages, a plurality of electrical strain gages in said body, each being positioned to be flexed by air flow in a separate one of said air passages and each having an electrical resistivity which changes in response to said flexing, and means for producing said control signals by detecting changes of said resistivity of each of said strain gages that are produced by air flow variations in said air passages.
17. An electronic harmonica for generating and transmitting digital control signals to a digital sound syn-thesizer comprising:
a harmonica body having a plurality of spaced apart air passages each corresponding to a different musical note, a direct current electrical voltage supply within said body, signal transmitting means for transmitting said digital control signals from said harmonica to said sound synthesizer, a plurality of strain gages secured to said body each having a flexible resilient element exposed to air flow within a separate one of said air passages and each having an electrical resistance which varies in response to flexing of said element, said electrical resistance being connected across said voltage supply, detector means for sensing changes of said electrical resistance of each of said strain gages and for producing a plurality of analog electrical signals each of which is indicative of changes of the electrical resistance of a separate one of said strain gages, means for repetitively generating a sequence of digitally coded addresses that identify successive ones of said strain gages, an analog to digital signal converter, means for reading out repetitive sequences of said analog electrical signals from said detector means in response to receipt of successive ones of said digitally coded addresses and for directing the resulting sequences of analog signals to said analog to digital signal converter to produce corresponding sequences of digital signal bytes that identify the amplitudes of different musical notes which are to be produced by said sound synthesizer, means for adding address code bits to each of said signal bytes to identify the musical note which each byte characterizes, and means for directing said sequences of signal bytes including said address code bits to said transmitting means.
a harmonica body having a plurality of spaced apart air passages each corresponding to a different musical note, a direct current electrical voltage supply within said body, signal transmitting means for transmitting said digital control signals from said harmonica to said sound synthesizer, a plurality of strain gages secured to said body each having a flexible resilient element exposed to air flow within a separate one of said air passages and each having an electrical resistance which varies in response to flexing of said element, said electrical resistance being connected across said voltage supply, detector means for sensing changes of said electrical resistance of each of said strain gages and for producing a plurality of analog electrical signals each of which is indicative of changes of the electrical resistance of a separate one of said strain gages, means for repetitively generating a sequence of digitally coded addresses that identify successive ones of said strain gages, an analog to digital signal converter, means for reading out repetitive sequences of said analog electrical signals from said detector means in response to receipt of successive ones of said digitally coded addresses and for directing the resulting sequences of analog signals to said analog to digital signal converter to produce corresponding sequences of digital signal bytes that identify the amplitudes of different musical notes which are to be produced by said sound synthesizer, means for adding address code bits to each of said signal bytes to identify the musical note which each byte characterizes, and means for directing said sequences of signal bytes including said address code bits to said transmitting means.
18. A signal generating harmonica for operating sound transducing equipment comprising:
a rectangular body having a plurality of in-dependent air passages from therein which are formed in a parallel alignment, each air of passage having an opening at one end and a restrictor means at the other end;
a plurality of air flow sensing means, one said air flow sensing means centrally located in each inde-pendent air passage and each of said air flow sensing means operable to generate signals proportional to variations in air flow rate and air flow direction in its associated air passage;
circuit means connected to each air flow sensing means operable to sense a signal generated by each air flow sensing means and to transmit a resulting output signal to a sound transducer whereby a player's blowing and drawing on said air passages can produce music sounds from said transducer.
a rectangular body having a plurality of in-dependent air passages from therein which are formed in a parallel alignment, each air of passage having an opening at one end and a restrictor means at the other end;
a plurality of air flow sensing means, one said air flow sensing means centrally located in each inde-pendent air passage and each of said air flow sensing means operable to generate signals proportional to variations in air flow rate and air flow direction in its associated air passage;
circuit means connected to each air flow sensing means operable to sense a signal generated by each air flow sensing means and to transmit a resulting output signal to a sound transducer whereby a player's blowing and drawing on said air passages can produce music sounds from said transducer.
19. The signal generating harmonica defined in Claim 18 wherein each air flow sensing means is a strain gage device.
20. The signal generating harmonica defined in claim 19 wherein each strain gage device includes a resis-tive circuit deposited on a flexible resilient element in communication with its associated air passage which varies in electrical resistance proportional to the degree and direction of flexure of said resilient element.
21. The signal generating harmonica defined in Claim 18 wherein the circuit means includes electrical strobe means which repetitively senses the signal of each air flow sensing means and develops an electrical signal representing the instantaneous air flow rate and direction in its associated air passage which is operable to generate an output signal for each air passage for generating musical notes in a sound transducer when air passes therethrough.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US31955789A | 1989-03-06 | 1989-03-06 | |
| US319,577 | 1989-03-06 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2011568A1 true CA2011568A1 (en) | 1990-09-06 |
Family
ID=23242754
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2011568 Abandoned CA2011568A1 (en) | 1989-03-06 | 1990-03-06 | Electronic harmonica for controlling sound synthesizers |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPH02298994A (en) |
| CA (1) | CA2011568A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109003595A (en) * | 2018-07-18 | 2018-12-14 | 冯金硕 | A kind of panpipes pattern digital music instruments having intelligent algorithm |
| CN108847205B (en) * | 2018-05-29 | 2020-04-24 | 成都磐基机电设备有限公司 | Digital harmonica |
-
1990
- 1990-03-06 JP JP2052861A patent/JPH02298994A/en active Pending
- 1990-03-06 CA CA 2011568 patent/CA2011568A1/en not_active Abandoned
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108847205B (en) * | 2018-05-29 | 2020-04-24 | 成都磐基机电设备有限公司 | Digital harmonica |
| CN109003595A (en) * | 2018-07-18 | 2018-12-14 | 冯金硕 | A kind of panpipes pattern digital music instruments having intelligent algorithm |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH02298994A (en) | 1990-12-11 |
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