US 3845684 A
The electronic automatic reset switch circuit comprises a plurality of on-off switches each connected between ground and the set input of an associated reset-set flip-flop. The reset inputs of all flip-flops are interconnected and a diode is connected across the inputs of each flip-flop. Momentary closing of any switch grounds the reset output of the associated flip-flop and that output remains grounded until another switch is closed.
Description (OCR text may contain errors)
United States Patent 1191 Herr 1 51 Nov. 5, 1974 Ernest A. Herr, 1850 Rominger Rd., Winston-Salem, NC. 27107  Filed: Nov. 14, 1973  Appl. No.: 415,732
Related US. Application Data  Continuation-impart of Ser. No. 349,233, April 9,
 11.8. C1 84/1.01, 84/1.l7, 84/DIG. 22,
84/470, 35/5  Int. Cl. Gl0h 1/00, GlOh 5/00  Field of Search 84/101, 1.03, 1.17, 1.24,
84/423-425, 433, 443, 470, DIG. 7, DIG. 22; 197/8; 35/5, 6
OTHER PUBLICATIONS John D. Lenk, Handbook of Logic Circuits, C. 1972, by Reston Publishing Company, Inc., Reston, Virginia, p. 43.
RCA Transistor Manual, Copyright 1967, by Radio Corporation of America, p. 41 l.
Millman & Taube, Pulse, Digital, and Switching Waveforms, McGraw-l-lill Book Co., Copyright 1965,
I3 I30 13b 14 p i p Primary ExaminerRichard B. Wilkinson Assistant ExaminerStanley J. Witkowski Attorney, Agent, or FirmBuell, Blenko & Ziesenheim  ABSTRACT The electronic automatic reset switch circuit comprises a plurality of on-off switches each connected between ground and the set input of an associated reset-set flip-flop. The reset inputs of all flip-flops are interconnected and a diode is connected across the inputs of each flip-flop. Momentary closing of any switch grounds the reset output of the associated flipflop and that output remains grounded until another switch is closed.
The musical instrument utilizes a plurality of electronic tone generators which feed an amplifier and speaker. A conventional typewriter keyboard is arranged so that certain keys, representing the melody to be played, work in conjunction with certain other keys, representing the chord to be played, and connected in the switch circuit above described so that in combination, the desired melody note and chord accompaniment are sounded together. Once a chord key is depressed, that chord continues to be utilized and sounded with additional melody notes even though the chord key has been released. This process will continue until another chord key is depressed. Circuitry is also provided for playing melody only. Music for the instrument is written as a succession of the alphabetic, numeric or punctuation signatures of the appropriate typewriter keys.
The instrument is also provided with chord selector switches and a stepping sequence switch arranged so that chords in a musical composition can be set up in advance on the chord selector switches and played by key operation of the sequence switch.
11 Claims, 10 Drawing Figures PATENIEDunv slam 38451684 sum 20; a
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ELECTRONIC AUTOMATIC RESET SWITCH CIRCUIT AND ELECTRONIC KEYBOARD MUSICAL INSTRUMENT INCORPORATING IT This application is a continuation-in-part of my application Ser. No. 349,233, filed Apr. 9, I973, and now abandoned.
This invention relates to electronic keyboard musical instruments. It is more particularly concerned with such an instrument which utilizes a conventional typewriter keyboard, of which certain keys trigger melody notes and certain other keys trigger chords.
Electronic organs are well known. In a true organ each key triggers an electronically generated tone which corresponds to one note, either of a melody or of a chord. Chords are played by depressing simultaneously the keys corresponding to the notes in the chord. The sound is produced by one or more loud speakers into which the amplified outputs of the tone generators are fed.
Chord organs, so-called, are also known. In these, certain keys trigger multi-note chords. Thus, a melody is played by depressing sequentially the keys corresponding to the successive notes of the melody and the accompaniment is played by depressing sequentially, in proper relation to the melody, the keys corresponding to the appropriate chords. The chord sound, as well as the sound of a melody note, continues as long as the appropriate key is depressed, and stops when the key is allowed to rise.
Instruments of the types above described are conventionally provided with keyboards quite similar to piano keyboards and are played in the same way as a conventional piano or organ is played. The keys of some of these instruments are marked with the musical signature of the note or of the chord which they trigger. In either case, the ability to read music, in greater or less degree, is required of the performer, and the manual dexterity required is in greater or less degree that of a pianist or an organist. These skills are not possessed by many people who would like to play a keyboard musical instrument and, therefore, represent a barrier to a wider enjoyment of such instruments.
It is an object of my invention to provide an electronic keyboard musical instrument which can be readily played by those who cannot read music and by those who have no piano keyboard dexterity. It is another object to provide an electronic keyboard instrument with both melody and chord keys marked with the markings of conventional typewriter keys. It is another object to provide such an instrument in which music can be played in the same way a letter is typed on a typewriter. It is still another object to provide such instrument with means for selecting in advance the chords to be played in a musical number and for playing the selected chords in selected order. It is yet another object to provide electronic apparatus useful in electronic keyboard musical instruments and in other devices in which the operation of one key-actuated switch to the on" position automatically sets all other key-actuated switches to the off" position. Other objects will appear in the course of the description of my invention which follows.
Without doubt the keyboard familiar to most individuals at the present time is the conventional typewriter keyboard and without doubt many more people can operate a typewriter in some fashion than can play the piano or organ. My instrument to be described utilizes a conventional typewriter keyboard with conventional key markings. Certain keys are responsible for supplying information that actuate electronic tone generators which generate single melody notes, a different note for each such key. Certain other keys are responsible for supplying information that actuates electronic tone generators which generate multiple note chords, a different chord for each key. Music to be played on my instrument is written as a succession of the alphabetic. numeric or punctuation signatures which appear on conventional typewriter keys corresponding in sequence to the notes of the melody and chords of the accompaniment. It is played by depressing the various keys of the keyboard in the sequence written, just as words are typed from copy on a typewriter.
An embodiment of my invention presently preferred by me is illustrated in the attached figures to which reference is now made.
FIG. 1 is a schematic diagram of my instrument illus- FIG. 3 is the same melody as that of FIG. 2 written only in the keyboard notation for melody and accompaniment of my invention;
FIG. 4 is a typewriter keyboard suitable for my instrument;
FIGS. 5 through 9 are schematics of a pair of chord keys and certain of their associated circuits illustrating the way in which the actuation of one chord key disables and resets a previously actuated chord key.
FIG. 10 is a schematic diagram of a modification of the apparatus of FIG. I.
My embodiment comprehends means for producing a plurality of musical notes and a plurality of chords. Each chord comprises a plurality of notes, usually not more than four. I find that 22 melody notes and I2 chords are adequate to recreate most popular music. I also provide means for playing melody unaccompanied, which means are actuated by a thirteenth chord key. As each chord must be available in combination with each melody note the total number of circuits must be 13 times 22 or 286. I further provide a plurality of manually operable selector switches each connected to each chord means and an electrically operated sequence switch connected to the selector switches so that operation of the sequence switch plays the preselected chords in succession. I prefer to use conventional npn transistor logic throughout.
My instrument (FIGS. 1 and 4) is provided with a plurality of melody keys of which three are illustrated, designated 10, 10a and 10b, and a plurality of chord keys of which three are illustrated, designated 13, 13a and 1312. As many melody keys and as many chord keys may be included as are desired, but the circuits for each melody key are merely duplicates of those for melody key 10 and the circuits of each chord are merely duplicates of those for chord key 13. Only the circuits for the two prototype keys will here be described.
Melody key 10 comprises a grounded contact I! and a normally live or ungrounded contact 12. Chord key 13 likewise comprises a grounded contact 14 and a normally ungrounded contact 15. Contact 12 of melody key is connected to one input 16 of a two-input nor gate 17. The other input 18 of gate 17 is connected with key 13 in a way to be described. As my apparatus comprehends l3 chords, contact 12 is also connected to one input each of 12 additional two-input nor gates corresponding to the remaining 12 chords. Three of these are shown as gates 17, 77 and 87. Other melody keys 10a and 10b comprise grounded contacts 110 and 11b, respectively, and ungrounded contacts 12a and 12b, respectively. Contacts 12a and 12b are connected to gates 17a, 77a and 87a and 17b, 77b and 87b, respectively.
Ungrounded contact of chord key 13 is connected to the set input 21 of a reset-set flip-flop memory circuit the reset output 22 of which is connected to input 18 of two-input gate 17. The reset input 23 of memory circuit 20 is connected to a busbar 33, which is common to the reset inputs of all the other memory circuits. Two of these are shown as memory circuits 20a and 20b. A diode 34 has its positive lead connected to reset input 23 and its negative terminal to set input 21 of memory circuit 20.
Appropriate direct current operating voltage is also supplied to two-input nor gate 17 and memory circuit 20 through conductors not shown. Output 19 of twoinput nor gate 17 is connected to the direct current operating voltage terminal 24 of chord composer 25. Chord composer is a buffered gate having four inputs, and an output terminal 30. Each of the four inputs is connected to a separate tone generator 26, 27, 28 and 29, respectively, which supplies a different frequency. The output of the chord composer is connected to the input of amplifier 31 which in turn drives a loud speaker 32.
I have mentioned that my apparatus comprises 286 two-input nor gates 17. Each of these requires and is associated with a separate chord composer 25. As my apparatus comprises thirteen different chords, a plurality of tone generators is required to supply the appropriate notes for each chord to the group of 22 chord composers connected to each chord key. One of the keys 13 which I have denominated a chord key is a melody only, or chord by-pass key.
Although my apparatus may contain additional elements to be described, its overall operation will best be understood if the operation of that much of it so far described is first explained.
The nor gates typified by gate 17 provide a positive output at output terminal 19 only when both inputs l6 and 18 are grounded. The memory circuits 20 are conventional flip-flops formed by two two-input and gates, the output of each being connected to an input terminal of the other. Understanding of the operation of memory circuits 20 will be facilitated by reference to FIGS. 5-9. Each of those figures shows two chord keys, l3 and 13a, with their associated memory circuits 20 and 20a. The numerals in the blocks representing memory circuits 20 and 20a indicated symbolically the voltage at the adjoining terminal of that circuit at that step in the sequence of operating conditions to be described. The chord keys l3 and 13a and their memory circuits 20 and 20a are typical of any two chord keys and memory circuits of my invention.
Those familiar with binary logic devices will recognize that the reset-set flip-flops and the two-input gates utilized in my apparatus respond only to two levels of signal voltage-0 or l-and provide only the same two levels of output. Hereinafter, I denominate a nominal 1 signal as positive and a nominal 0 signal as ground. I also denominate two signal inputs or outputs which are both nominally 0 or nominally l signals of the same character.
FIG. 5 illustrates the conditions obtaining when no chord key is depressed and there is no output from speaker 32. Positive voltages appear at inputs 21 and 23 of memory circuit 20 and at its reset output 22. That output, which is connected to input nor 18 of two-input gate 17, is effectively open circuited. The same conditions apply to memory circuit 20a. When chord key 13 is depressed the conditions obtaining in the two sets of circuits are then shown in FIG. 6. Input 21 of memory circuit 20 is grounded, as is input 23 through diode 34. A positive voltage still appears at output terminal 22. As all reset inputs 23, 23a, etc. are connected by busbar 33, input 23a of memory circuit 20a is also grounded. A positive voltage still appears on input terminal 21a and on output terminal 22a. Therefore, there is still no output from speaker 32.
When key 13 is released, however, the conditions are those shown in FIG. 7. A positive voltage again appears on terminal 21 and, through diode 34, on terminal 23. This results in ground condition at output terminal 22. Input terminal 21a of memory 20a continues to show a positive voltage, and the positive voltage now on busbar 33 appears on input terminal 23a of memory circuit 20a. Its output terminal 22a therefore continues to show a positive voltage.
The ground condition at terminal 22 is applied to terminal 18 of two-input nor gate 17. A key 10 representing the first note of the melody is then depressed. This supplies ground directly to input 16 of two-input nor gate 17 and causes that gate to produce a positive direct current voltage at its output 19. Although memory circuit 20 supplies ground to the chord input terminal of 21 additional two-input gates and key 10 supplies ground to the melody input terminal of 12 other twoinput gates, none of these will produce an output signal.
The output 19 of two-input nor gate 17 is adjusted to a value equal to the operating voltage of chord composer 25. When this voltage is applied to operating voltage terminal 24 of that chord composer, the latter closes the circuits between the tone generator inputs 26, 27, 28 and 29 and the output 30, and allows all those frequencies to be amplified by amplifier 31 and reproduced as music through loud speaker 32.
One of the notes of the chord will be that selected by melody key 10. If now another melody key, 10a, is depressed, another two-input nor gate, 17a, will be actuated, but it will only be one of the 22 strapped to memory circuit 20 as has been mentioned. Therefore, the chord produced will have the same three chord notes as that first produced but a different melody note.
A new chord is generated by depressing another chord key, such as 13a. The conditions with respect to keys l3 and 13a and their associated memory circuits 20 and 20a are then those shown in FIG. 8. Depressing key 13a grounds input 21a of memory circuit 20a. Input terminal 23a is also grounded through diode 34a, and this ground is extended by busbar 33 to input terminal 23 of memory circuit 20. Output terminal 22 of memory circuit 20 is thus switched to a positive voltage, and the chord corresponding to key 13 is cut off. Both inputs of memory circuit 20a are grounded and its reset output 22a is positive. The condition of memory circuits and 20a are the reverse of FIG. 6, and neither circuit produces a chord. When key 13a is released, the conditions of memory circuit 20 and 20a, shown in FIG. 9, are the reverse of those of FIG. 7, and the ground at output 22a of memory circuit 20a is supplied to terminal 78 of two-input nor gate 77. Gate 77v is identical to gate 17 previously described.
It is evident, therefore, that the chord corresponding to key 13 will continue to be heard until another key, 13a, is depressed and released, and that operation resets memory circuit 20.
The thirteenth chord key previously mentioned which is depressed when melody only is to be played is connected to a memory circuit and a plurality of twoinput gates in the same way as the other chord keys. The chord composers connected with the thirteenth chord key, however, are each connected to a single tone generator only.
The remainder of the apparatus shown in FIG. 1 will now be described. It provides for the preselecting of the chords in a piece of music and the playing of those chords in an automatic sequence. For this purpose my instrument is provided with a plurality of manually operated selector switches, of which three are shown, designated 38, 38a and 38b. The total number of selector switches 38 provided in an instrument should be at least equal to the number of successive chords in the accompaniment of the longest piece expected to be played on the instrument. As all selector switches are identical only switch 38 will be described in detail. It is a rotary switch having a plurality of circumferentially spaced contacts of which three are shown, designated 39, 40 and 41. The number of such contacts is equal to the number of chords provided in the instrument.
Switch 38 also has a rotary contact arm 42 which is movable manually into successive conductive engagement with contacts 39, 40 and 41. Contact arm 42 is provided with a conducting lead-out terminal 43. Switch contact 39 is connected by conductor 66 and busbar 44 with live contact 15 of chord key 13. Switch contact 40 is connected by conductor 67 and busbar 45 with contact 15a of chord key 13a. Switch contact 41 is connected with conductor 68 and busbar 46 with contact 15b of chord key 13b. The corresponding contacts of the other switches 38a and 38b are likewise connected with busbars 44, 4S and 46. Each switch also has a zero position unconnected with any chord key.
My apparatus is also provided with an electrically operated sequence switch 48. This switch is a rotary tap stepping switch with spaced circumferential contacts 49, 50 and 51. The number of those contacts equals the total number of selector switches 38 and the switch is also provided with a zero position unconnected to any selector switch. Contact 49 is connected by conductor 52 to terminal 43 of selector switch 38. Contact 50 is connected by conductor 53 to terminal 43a of selector switch 38a, and contact 51 is connected by conductor 54 to terminal 431) of selector switch 38b. Rotary contact arm 55 of sequence switch 48 is connected through conducting lead 56 to ground.
Contact arm 55 of sequence switch 48 is caused to rotate around the switch circumference from one contact to the next in steps by a conventional solenoid rachet device 58. One terminal of the solenoid 58 is connected by conductor 59 to ground and to a key 63 which I prefer to be a typewriter space bar. The other end of the solenoid is connected by conductor 60 to one terminal of a source of power, such as a battery 61. The other terminal of battery 61 is connected by conductor 62 to live contact 64 of key 63.
The switch apparatus above described is used in place of chord keys 13 as may be desired. If the operator of the instrument wishes to use chord keys 13 in the way which has been described he manually turns switch arm 42 of the selector switch 38 to the zero position and does the same with the arms of all the other selector switches. Those switches are, of course, provided with knobs and face plates which indicate the chord key corresponding to eachposition of the switch arm. Alternatively, the operator can cause the contact arm 55 of sequence switch 48 to rotate to its zero position in the manner to be described. In either case, the connection between the ground on'conductor 56 and live contacts 15, 15a, etc. of chord keys 13, 13a, etc. is broken.
If the operator wishes to use the switching apparatus he first turns contact arm 42 of switch 38 to the contact corresponding to the first chord of the composition to be played. In FIG. 1 that contact is indicated to be contact 41. He then turns contact arm 42a of switch 38a to the contact corresponding to the second chordcontact 39a. He turns contact 42b of switch 38b to the contact corresponding to the third chord-contact 40b, and so on until every chord in the composition is set up on a selector switch. It is evident from FIG. 1 that the operation above described connects arm 42 with contact 15b of key 13b through conductors 68 and 46, arm 42a with contact 15 of key 13 through conductors 66a and 44, and arm 42b with contact 15a of key 13a through conductors 67b and 45, and the contact arms of the remaining selector switches with the live contacts of the appropriate chord keys. It is, therefore, only necessary to connect the contact arms of the selector switches successively to ground to cause those chords to be sounded in succession.
This connection is accomplished by sequence switch 48. When key 63 is depressed so as to make contact with live contact 64 current from battery 64 flows through solenoid 58. The armature of the solenoid is attracted, operating the conventional stepping switch ratchet mechanism which moves contact arm 55 from the zero position to contact 49. This connects arm 42 of selector switch 38 to ground through conductors 52 and lead 56. The chord corresponding to chord key 13b is thus set up and is played when a melody key is depressed, in the way which has been described. When the next chord is to be played the operator depresses key 63 again, which brings about movement of arm 55 to the next contact 50 in the way described, and so renders the next chord ready to be played. Thus, the operator, having selected the appropriate chords in advance, need only depress key 63 momentarily at the proper time to have the chord played.
FIG. 10 illustrates a modification of the apparatus of FIG. 1. Only one melody key and one chord key and memory are shown. In the apparatus of FIG. I as it has been described herein the melody key switch 10 when depressed connects contact 12 to ground. In the modification of FIG. 10 melody key 10 is connected to the positive terminal of voltage source 75, such as a battery, the other terminal of which is grounded. Contact 12 is connected to one input 16 of a two-input and gate 80. The other input 18 of that gate is connected to the set output 74 of memory circuit 20. All other connections of the remaining memory circuits and gates remain unchanged.
The operation of chord key 13 and memory circuit 20 in the apparatus of FIG. is the same as their operation in FIG. 1, which has been described. When melody key 10 of FIG. 10 is depressed, it connects the positive voltage of source 75 to one input 16 of two-input and gate 80. When chord key 13 is depressed and released, the voltage at set output 74 of memory circuit is the opposite of that at terminal 22, that is to say it is a positive voltage, and that voltage is applied to the other input 18 of and gate 80. And gate 80, therefore, produces a positive voltage at its output 19, and that voltage is applied to terminal 24 of chord composer as before.
The keys of my keyboard carry the markings of conventional typewriter keys-letters, numbers and punctuation marks and are arranged in the same way as a typewriter keyboard. I prefer to use the bottom row of the keyboard, as far as possible, for my chord keys, 7
as shown in H0. 4. Music for my instrument is written as a sequence of typewriter key markings or signatures, as may be seen in FlG. 2. The letter C below the first note of the first line of music in that figure indicates the key for the initial chord, and the letter R is the initial melody note. in the next bar the chord is changed to that represented by key V. The melody is accompanied by that same chord throughout the remainder of the first line and the first three bars of the second line; in the fourth bar a new chord is played by depressing key B, and so on. The music is compactly written as a sequence of the characters, as is shown in FIG. 3. The chord keys are indicated as subscript characters and timing information is conveyed by underlining the appropriate melody characters.
in the foregoing description I have referred to chord composer 25 as a four-input gate, but it is operated as a four-pole single throw relay. While I have described keys 10 and 13 as having one grounded contact, I include under the term ground a busbar common to one contact of each key and other points at ground potential, whether or not it is actually grounded. My apparatus is not, of course, limited to 22 melody keys and 13 chord keys, but may comprise any number of either. It requires only one amplifier and one speaker, but two or more amplifiers and speakers may be employed.
In the foregoing specification l have described a presently preferred embodiment of this invention; however, it will be understood that this invention can be otherwise embodied within the scope of the following claims.
' I claim:
' 1. Apparatus comprising a plurality of reset-set flipflops, an on-off switch connected between ground and the set input of each flip-flop, a reset bus bar connecting-the reset inputs of all the flip-flops, and a diode connected between the set and reset inputs of each flipflop with its positive terminal connected to the reset input, the on-off switch being a key operated chord switch, a plurality of key-operated melody note on-off switches, a plurality of two-input gates equal to the product of the plurality of melody notes by the plurality of chords. each gate being adjusted to produce a positive output when both input signals are of the same character, means connecting each melody note switch between a signal source and one input of a plurality of the two-input gates equal to the number of chords,
' means connecting the output of each reset-set flip-flop having the same character as the signal source with the other input of the plurality of the two-input gates equal to the number of melody notes, a plurality of multiinput chord composers equal to the plurality of twoinput gates, each chord composer being connected to the output of a single two-input gate and activated by the output from that gate to connect the chord composers inputs with its output, a plurality of tone generators connected to the inputs of the chord composers, and means connecting the outputs of the chord composers with a sound-producing device.
2. Apparatus of claim 1 in which the chord composer is a multi-input gate, each tone generator is connected to one input of that gate, and the output from the twoinput gate connected to its melody note switch provides the operating potential which opens the multi-input gate.
3. Apparatus of claim 1 including chord composers having a single tone generator each connected thereto.
4. Apparatus of claim 1 including a plurality of chord composers equal to the number of melody keys, each chord composer being connected to a single tone generator.
5. Apparatus of claim 4 including a chord key and a reset-set flip-flop circuit connected with each of the chord composers which is connected to a single tone generator.
6. Apparatus of claim 1 in which the keys operating the melody note switches and the keys operating the chord switches are arranged in the form of a typewriter keyboard.
7. Apparatus of claim 6 in which the keys carry distinguished indicia in the form of typewriter characters and are arranged in the order of the characters of a typewriter keyboard.
8. Apparatus of claim 1 including a plurality of manually operable selector switches, each having a separate contact connected to each chord switch, a multicontact sequence switch, means connecting the arm of each selector switch to a separate contact of the sequence switch, means connecting the arm of the sequence switch to ground, and electrical means including an on-off switch for operating the sequence switch.
9. Apparatus of claim 8 in which the keys operating the melody note switches and the keys operating the chord switches are arranged in the form of a typewriter keyboard and the switch for operating the sequence switch is operated by the space bar of the typewriter keyboard.
10. Apparatus of claim 1 in which the signal source for the melody note switches is ground, the two-input gates are nor gates, and the reset output of each resetset flip-flop is connected with the other input of the plurality of two-input gates equal to the number of melody notes.
11. Apparatus of claim 1 in which the signal source for the melody note switches is a voltage source, the twoinput gates are and gates, and the set output of each resetset flip-flop is connected with the other input of the plurality of two-input gates equal to the number of melody notes.
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