NZ501735A

NZ501735A - Method of converting the output of a computer keyboard having a numerical keypad into MIDI-format signals suitable for input to MIDI-compatible devices

Info

Publication number: NZ501735A
Application number: NZ501735A
Authority: NZ
Inventors: Anthony Romagnano; David John Ambry
Original assignee: Dte Solutions Pty Ltd
Priority date: 1997-06-18
Filing date: 1998-06-18
Publication date: 2001-06-29
Also published as: CA2295201A1; AUPO741897A0; WO1998058363A1

Abstract

A signal conversion method and a device for interfacing a PC keyboard 14 with a MIDI sound-generator such as a sound-card fitted within a computer 20 or a standalone sound generator 22. The interface unit can also take inputs from a MIDI keyboard 18 and a PC joystick 16, the latter being used for sound-bending. The interface includes input and output connectors 44, 48, 52, 50, 54 and 62 and associated adaptor circuits 46, 60, 58, 56 and 64 for communication with a microprocessor 40. Read only memories 42 and 43 containing factory and user pre-set data are accessed by the microprocessor 40. In one mode of operation, PC signals generated by the keyboard's keypad are converted into MIDI signals corresponding to the notes of a selectable musical scale such that the root note of the scale is elicited by the same keypad key.

Description

TITLE: COMPUTER KEYBOARD-MIDI INTERFACE TECHNICAL FIELD This invention relates to signal conversion means for adapting the signals output by 5 a standard keyboard - and, optionally, a standard joystick - of a PC (personal computer) to devices (equipment, firmware or software) such as sound cards, sequencers, synthesisers, composers and sound modules which conform to the MIDI (Musical Instrument Digital Interface) protocol established by the International MIDI Association. The signal conversion means, which may be implemented in hardware, 10 software and/or firmware, thus serves as an interface between a PC keyboard and a MIDI device.

A standard computer keyboard (generally referred to herein as a PC keyboard) typically has the following components: • A set of symbol keys comprising about four rows of alphanumeric and punctuation keys having about 10 keys per row. The layout of the symbol keys normally follows that of the QWERTY typewriter, but any other layout of these keys — such as that of the Dvorak typewriter— may be used. The set of symbol keys is normally located centrally or somewhat to the left on the keyboard. 20 • A bottom or fifth row of keys below the symbol keys, comprising at least the spacebar but often including a few function keys on either side of the spacebar. A set of lefthand control keys grouped to the left of the symbol keys and normally including at least three of the following keys—Tab, left-Ctrl, left-Shift, left-Alt and Caps-Lock. The keys of this group are positioned in line with at least 25 three rows of the symbol keys.

A set of righthand control keys to the right of the symbol keys and normally including at least three of the following keys — Backspace, Enter, right-Ctrl, right-Shift, right-Alt, Ins, Del and Home. The keys of this group are normally positioned in line with at least three rows of the symbol keys.

• A set of four courser keys, normally to the right of the set of symbol keys, marked with left, right, up and down arrows. These are sometimes called arrow keys.

Printed from Mimosa WO 98/58363 PCT/AU98/00475 2 A set of at least 10 programmable function keys, usually 12 keys in one row above the symbol keys and marked F1 to F12.

A set of 15-20 keys arranged in the form of a calculator-style numeric keypad. The keypad may not be integrated into the rest of the keyboard but, instead, 5 formed as a physically separate unit connected to it by a suitable cable.

Dedicated electronic circuitry which scans all keys and detects the depression and release of any one or more keys (alone, in sequence or in combination) and generates a corresponding standard PC-format digital signal.

An example of such a keyboard is the IBM-102.

BACKGROUND TO THE INVENTION Where a PC keyboard is used to generate music it is usual to allocate some keys (generally symbol keys) to simulate portion of a piano keyboard. This will enable a 15 person to play tunes as if on a piano. Other keys can then be used to shift octaves and assign voicings to the 'piano' keys. It is also known to use yet other keys of the PC keyboard to generate chords. However, the present invention is based upon the appreciation that the keypad of the PC keyboard can be used to manually generate an arpeggio-like sequence of notes in a given scale or chord, as is often done by a 20 double-bass or base guitar in a small band, or to generate a regular sequence of drum percussion sounds typical of a drummer using a drum set to maintain a regular beat pattern. In other words, it was appreciated that the keypad is well adapted to rhythmic accompaniment with harmonic variation.

The mechanical conversion of a computer keyboard to a little over an octave of a piano keyboard is disclosed in US patent 4,352,313 to RCA Corp. A fold-down or screw-on piano-key overlay is attached to the PC keyboard so that its black piano notes operate some of the PC number keys and its white piano notes operate some of the PC letter keys. While signal conversion means is employed to interpret the 30 keyboard output, a MIDI interface is not used, and many of the PC keys are obscured by the piano overlay and are therefore not available to effect additional musical control. No use was made of a numerical keypad.

Printed from Mimosa WO 98/58363 PCT/AU98/00475 3 It has been further proposed to alter the shape some of the keys of a PC keyboard to make them look more like those of a piano, thereby obviating the need for an overlay. In US patent 5,646,648 and US design patent 367,858 to IBM, the shaping and grouping of the function keys and the symbol keys of a PC keyboard are altered 5 to simulate an octave and a half of piano keys. The accessibility of all the keys is preserved so that the user can enter music and lyrics at essentially the same time. IBM patent 5,646,648 envisages the use of an interface comprising a sound-controller integrated-circuit or a MIDI-compatible soundcard. While octave-shift control using the Shift and Caps Lock keys is also disclosed, no use is made of the keys of the 10 numeric keypad.

US patent No. 4655117 to Roose discloses the use of a non-standard PC keyboard that is said to utilise the skills of touch-typists who are not familiar with piano-style keyboards. At least five new keys are added to each end of each row of symbol keys. 15 When in 'music mode', the tonal progression between the notes generated by keys in each row of keys corresponds to a few octaves of a different diatonic scale. Thus transposition is simply a matter of using the same fingering on a different row of keys. The Roose device allows the generation of polyphony or chords, requires an expensive custom-made key board, is played in a manner quite different to a piano, 20 does not utilise a MIDI interface and does not exploit a numeric keypad for the generation of sounds.

US patent 5,088,378 to DeLaTorre offers a polyphonic system with melody, chord generation and transposition from a PC keyboard, the use of a keypad or MIDI 25 interface not being disclosed. The keyboard is essentially divided in half, those on the left being multiplexed to generate all 48 chords, and those on the right being multiplexed to generate the melody over a range of five or six octaves. The operation of any one of 24 keys on the lefthand side of the keyboard, by itself or in combination with the left Shift key, will generate any one of the 48 possible chords. The operation 30 of any one of 26 keys on the right (in combination with another key on the right) is used to generate 31 tones, or nearly three octaves. The tone of the selected melody note is shifted down by a semitone when the melody key is further combined with the Printed from Mimosa WO 98/58363 PCT/AU98/00475 4 operation of the right Shift key. Not only is the arrangement of musical notes/keys quite different to that of a piano (so that a novel notation is required for sight-reading), but the three-level multiplexing of the melody keys is as foreign to a typist as it would be to a pianist.

US patent No. 5,565,6417 to Gruenbaum discloses the use of a standard PC keyboard (together with foot-operated switches) to generate any desired tone or tone-interval in any desired scale (or non-scalar tone progression) via a MIDI interface. There is no one-to-one correspondence between computer keys and musical notes 10 (key functions being entirely under software control), a 'relativistic' principle being employed whereby a sequence of key-presses indicates a series of tonal intervals. The result is an extremely versatile (but complex) music input device which bears little relationship to the piano keyboard, requires considerable programming skills and knowledge of musical theory. However, the numeric key pad of a standard PC 15 keyboard is not used to effect musical inputs.

Various proposals have been advanced to employ hand-held electronic calculators to generate musical notes. The keypad of a PC-keyboard is, of course, similar to some hand-held calculators. However, these proposals are directed to the generation 20 of melodies or tunes rather than rhythmic accompaniment. For example, US patent No. 4,519,044 to Munetsugu teaches the use of some calculator keys to generate tones and others to effect a shift of octave or musical scale. When such a calculator is switched to 'music mode' and the desired musical scale has been selected, the appropriate key signature and staff are displayed on the LCD screen of the calculator. 25 A similar proposal for using an electronic calculator to generate music was disclosed in US patent 5,1'51,873 to Hirsh who saw great benefit in allocating specific calculator keys to specific tones and half tones. The restrictions of the calculator keypad mean that such devices cannot be made to resemble a piano keyboard and must have highly restricted musical functions. There is therefore no suggestion of a MIDI 30 interface for such calculators.

Printed from Mimosa OBJECTIVES OF THE INVENTION It is an objective of the present invention to provide signal-converter or interface means that will enable a PC keyboard to drive a MIDI device in a manner which is both versatile and yet familiar to someone with some knowledge of the piano 5 keyboard and a variety of musical scales. It is desirable for the converter to make use of the numeric keypad of the PC keyboard to facilitate rhythmic and varied accompaniment in a manner which is consonant with a chosen musical scale or the last-played chord. It is also desirable to be able to employ the keypad to manually effect common drumming patterns. However, it is not essential for all embodiments of the invention 10 to meet all these objectives.

OUTLINE OF INVENTION As already indicated, the present invention is based upon the realisation that the numeric keypad of a PC keyboard is very appropriate for the manual input in real-time 15 of a sequence of musical notes or sounds which, if desired, can be harmonised with other musical settings of the keyboard, such as chords or music-key. For convenience, this type of musical input will be called 'manual sequencing'. It is of great value in real-time improvisation and is, in that regard, quite distinct from the function of programmable sequencers by which a sequence of sounds can be recorded during 20 a composing or a programming session then replayed in a play mode. In addition to employing the keypad in this way, it is preferable to use the lefthand group of control keys to generate chords and to use most of the first four rows of PC symbol keys as two banks of piano-style keys for musical input. The keys of the lefthand control group used for chord generation may therefore be called 'chord keys'.

One way of utilising the numerical keypad in harmonisation with the chord keys is to automatically map the component notes of the musical scale of each chord as it is played with the left hand onto the keypad so that consonant variations can be played in that scale with the right hand, preferably in a lower register to provide bass 30 accompaniment. This allows bass variations to be generated using consistent fingering from chord to chord without need to be concerned with sharps and flats. For example: if the chord C-major is played, the root note (C) of that chord is allocated to Printed from Mimosa 6 keypad key 1 and keypad keys 2, 3 etc are allocated to successive notes of the C-major scale; if the chord of F-major is played, the root note (F) of that chord is allocated to keypad key one and keypad keys 2,3 etc are allocated to successive notes of the F-major scale; the fingering of the keypad is thus consistent irrespective 5 of scale. There are sufficient keypad notes to cover nearly two octaves above the root note, if desired. This permits simple arpeggios or the like to be played with the right hand which are always in the same scale as the last-played chord. Preferably, upon power-up, the root note on the keypad is a bass note two octaves below the root note of the chord played using a chord key. This mode of keypad use is hereafter referred 10 to as the 'bass mode'.

Another way of utilising the numerical keypad (selected by the use of appropriate control keys) is to fixedly assign the notes of a selected musical scale to the keypad keys so that the scale of the keypad does not change with the scale of the chords. 15 Thus, a conventional musical octave would be assigned to keypad keys 1-7, with key 8, 9 ... being assigned to notes which are an octave higher than those represented by number keys 1,2.... Similarly, a pentatonic scale would be played with keypad keys 1-5 and repeated in the higher register with keys 6-9. Again, this allows for the easy rendition of scales and arpeggios in a manner which is much more straightforward 20 than with the conventional layout of piano keys. This mode of keypad use is herein referred to as the 'scale mode'.

Yet another way of utilising the numerical keypad (again selected by the use of appropriate control keys) is to map percussion sounds onto its keys so that, for 25 example, repeated manual operation of keys 1 -3 in sequence will reproduce a familiar drum and cymbal backing in, say, 4:4 or 6:8 time. Alternatively, the same drum may be assigned to three adjacent keypad keys (say, 4,5,6) so that drum-rolls can be easily effected. This mode of utilising the keypad is herein referred to as the 'drum mode'.

As indicated, it is preferable to allocate most of the PC symbol keys to a piano-style layout in two pairs of rows, so that black piano notes are represented in the first or Printed from Mimosa 7 upper row of a pair (the first or upper row being that furthest from the keyboard user) and the white piano notes are represented in the second or lower row of that pair. The central group of computer-keys is thus adapted to play montonal melodies or leads as if on a piano. The keys of this group will therefore be referred to as the 'piano' 5 keys. Their use will be familiar to any one with a rudimentary knowledge of Western musical notation.

As also indicated above, it is preferable to assign the lefthand control keys (together with some of the lefthand symbol keys) to the playing of chords and it is convenient 10 to refer to the latter keys as chord keys in a musical context. The musical key of the chords played, as well as the multiplexing of the chords on the lefthand PC keyboard group, is preferably determined by control keys in that group and/or by use of the PC keyboard function keys. The keys used to generate chords in the music mode will therefore be referred to as 'chord' keys.

Given the key allocations indicated above, and as already noted, it is convenient to use the PC function keys to select the mode of operation of the keypad and to program desired percussion sounds onto the keypad (for the drum mode). It is also convenient to assign note variation or modulation (eg, voicing, octave-shift, velocity 20 and instrument selection) affecting the piano, chord and keypad keys, to the righthand group of PC control keys. For example, the up and down arrow keys can be used to increase and decrease the velocity of attack of sounds, the left and right arrow keys can be used for down-octave and up-octave shifts, the Page-Up and Page-down keys can be used to effect corresponding transpositions of musical key, preferably for the 25 chords and scales executed on the keypad as well as the piano notes. Two further function keys in the righthand PC control group may be used for raising and lowering output volume (when the keyboard is in the music mode).

It is further envisaged that the PC function keys (normally F1-F12) may be allocated 30 to the generation of percussive sounds, such as drums, sticks, handclaps, cymbals, triangles and the like, though the assignment of other voicings to these keys is also Printed from Mimosa 8 possible. If desired, the programmable function keys are multiplexed under keyboard or software control so that multiple 'banks' of voicings can be selected.

Preferably, upon 'powering up' the keyboard and MIDI interface in the music mode, 5 the chord keys are set to the chords of C major, the keypad is mapped with the notes of C major starting from two octaves below the root note of the chord keys, and most of the PC function keys are set to percussion. This provides the four common components of many popular music bands (piano/lead, chords, bass backing and drums).

In summary, the invention comprises signal conversion means to effect the conversion of PC keypad signals into MIDI signals with any of the musical effects indicated above. It also comprises a method and an interface means for utilising a standard PC keyboard with a numeric keypad to achieve these effects. Optionally, the 15 signal conversion means and the method may incorporate the use of a PC joystick to effect the bending or wha-wha variation of any note or chord played on the keyboard.

It will be appreciated that the invention may be implemented in hardware and 20 firmware as a interface device which is physically independent of the keyboard and PC, as will be described in the following example. Alternatively, such a hardware/firmware device can be incorporated in the keyboard case or on the soundcard of the computer. Alternatively again, the signal conversion means may be partially or entirely implemented in software running on the PC.

DESCRIPTION OF EXAMPLES Having broadly portrayed the nature of the present invention, particular examples will now be described by way of illustration only. In the following description, reference will be made to the accompanying drawings in which: Figure 1 is a diagrammatic perspective view of a MIDI music system employing the MIDI interface of the chosen example of the present invention, Printed from Mimosa 9 Figure 2 is a plan view of a standard PC computer keyboard showing how general music functions are assigned to key groups in the chosen example, the keys being marked to indicate their normal PC functions, Figure 3 is a plan view of the keyboard of Figure 2 in which the keys are marked to indicate their musical functions, Figure 4 is a tabulation relating PC keypad codes to MIDI codes for the three manual sequencer modes, Figure 5 is a functional block diagram of the interface unit of the chosen example and some of its possible connections, Figure 6 is a system chart summarising the broad musical functions of the 15 keyboard and signal converter of the chosen example.

Referring to Figure 1, the music system 10 of the chosen example is based upon a free-standing hardware-implemented keyboard-to-MIDI interface 12 that (i) accepts inputs (alone or in combination) from a standard PC keyboard 14, a standard games 20 joystick 16 and/or a conventional piano-style MIDI keyboard 18, and (ii), delivers MIDI-coded outputs to the MIDI-input of the soundcard (not shown) of a PC 20 and/or to a commercial MIDI-compatible sound-generator 22 (eg, a Yamaha MU50 or a Roland SC-50). The multi-channel analogue outputs generated by the soundcard of PC 20 and sound-generator 22 are fed to a conventional amplifier 24 that drives a 25 pair of conventional loudspeakers 26. It will be appreciated that some standard PC keyboards have sockets for the connection of joysticks and that it is immaterial whether joystick 16 is connected direct to interface 12 or indirectly via keyboard 14.

Figures 2 and 3 show the manner in which the principal musical functions are 30 assigned to the keys of PC keyboard 14, Figure 2 showing PC key-caps and Figure 3 showing musical key-caps . In both Figures 2 and 3, the keys are allocated to four groups according to musical function, each group being identified by a reference Printed from Mimosa numeral and by name. For the sake of clarity, the following key-cap abbreviations are used in Figure 2: PS = Print Screen, SL = Scroll Lock, PB = Pause Break, HM = Home, PU = Page Up, PD = Page Down, NL = Number Lock, and Ent = Enter. The key markings employed in Figure 3 will be identified below, but it will be appreciated 5 that key functions can change with the use of function control keys.

Most of the PC symbol keys are assigned to the central and large piano group 30. The keys of the first row of this group — bearing semi-tone symbols — represent the black keys of about one an a half piano octaves, while the keys of the second row 10 (including the large Enter key) represent most of the white notes of these octaves, the notes represented by these keys also being marked on the faces of the keys. The same pattern is repeated in the third and fourth rows of the keys of the piano group 30, though progressively fewer keys are assigned to the piano group in the latter rows. Preferably, the diatonic piano octaves represented by the two pairs of key rows 15 are contiguous.

To the left of piano keys 30, and including (i) the lefthand PC control keys, (ii) the far left symbol keys (namely, ~, 1, 2, Q, W, A, S, Z and X) and (iii) the spacebar (marked 7), is the group of chord keys 32. In this example, there are twelve chord keys (the 20 chords for the key of C being indicated by markings on the faces of the keys in Figure 3) and four chord control keys (m7, M7 and 7) by the use of which all 48 chords can be generated. Pressing the m7 and C chord keys together will generate a PC keyboard signal that is converted by interface 12 into the MIDI code for the component notes of the C minor 7th chord , M7 and C will elicit the C major 7th chord 25 , m and C will elicit C minor, while 7 (spacebar) and C will elicit the dominant C7th chord. The allocation of the C major chords to the chord keys 32 is default, that is it occurs upon power-up or reset (key RST Figure 3).

The keypad group 34 is labelled 'Bass, Drums and Scales' to indicate the three 30 modes of operation already indicated. In Figure 3, the key-caps are marked to show the default allocation of musical notes. This is the sale of C major with the root note Printed from Mimosa WO 98/58363 PCT/AU98/00475 11 (PC keypad key 1) set two octaves below the root note of the C major chord elicited by chord-key C of chord group 32.

Most of the remainder of the keys are allocated to the 'Control & Drums' group of keys 5 36 which also perform modulation functions.These keys comprise the PC function keys and the righthand group of PC control keys. In fact, the modulation functions are performed by most of the righthand PC control keys, together with two keys in the fifth row. The key marked 'MIDI-out' is used to select a prerecorded MIDI signal for transmission to the sound system along with the keyboard output; that marked 'MIDI-10 in' is used to select a MIDI input signal for transmission to the sound system instead of the keyboard output. The key marked 'MP' is used to toggle a multi-layering function in which the notes played are sent to more than one MIDI channel and therefore given more than one voicing. The key marked 'KEY' is used to shift the musical key of the keypad group 34 when in bass mode. The keys marked 'TSP t' 15 (with an up-arrow) and 'TSP J* (with a down arrow) are used to respectively effect the up-scale and down-scale transposition of the chords elicited by key group 32 and to the bass and scales notes generated by keypad group 34. Operation of the key marked 'ACB' causes a bass note to be added to all chords elicited by key group 32, the added base note being one or two octaves below the root note of the chord. The 20 key marked 'ABS' is used to select the scale to be played in the scale mode of the keypad group 34. The keys marked 'V J' and .'V t' are used to decrease and increase the volume of the music output to the sound system; those marked 'OCT*-' and 'OCT-*' are used to shift the octave of the notes output by the keys of the piano group an octave down and an octave up respectively; while those marked 'VEL"1" and 'VEU' 25 are used to effect an increase or decrease in the attack of the sound elicited by the keys of the piano group, the keys of the chord group and the keys of the manual sequencer group.

Finally, the PC function keys, together with PC keys Esc, Print-Scrn, Scroll-Lock and 30 Pause-Break (which form part of the Control & Drums group 36), are primarily used to multiplex and determine the musical functions of the keys of the other groups. The key markings indicating musical functions shown in Figure 3 will now be briefly Printed from Mimosa 12 explained. The key marked 'RST' effects the resetting of the keyboard to its default settings. Those marked 'CRD' with numbers 1-3, when used with a control key marked C-1 (located in the fifth row of keys), effect changes in the allocations of chords to the chord keys of group 32, while those marked 'SCL' 1-2, when used with 5 key C-1, effect the selection of the musical scale employed in the scale mode of the keypad group 34. The use of the four keys marked 'DRM' 1-4, when used with a control key marked C-2 (located in the fifth row of keys), effects the selection of the percussion or drum kits applied to the PC function keys (in the drum mode) and to the keyboard group 34 in the drums mode. Upon power-up, the PC function keys are 10 assigned a default set of percussion sounds, including drums and, unless used with control keys C-1 and C-2 will elicit the default sound. The key 'FX', when used with control key C-2, allocates pre-recorded sound effects to the piano keys. That marked 'SEQ' is used to control a sequencer connected to the interface, while that marked 'MIDI CC' is used to place the joystick output onto the MIDI continuous controller 15 channel to effect pitch bend or a wha-wha effect.

The tabulation of Figure 4 illustrates the conversion — effected by interface 12 -- of the PC code (in decimal format) output from the PC keypad into a MIDI code (also in decimal format) for each of the three music modes of operation of the keypad when 20 used as a manual sequencer. The MIDI codes will normally be output on any one or more of MIDI piano channels 4-6. Thus, upon power-up, pressing PC keypad key 0 generates PC-keyboard code 99. This is received by interface 12 and converted to MIDI code 31 which indicates a frequency corresponding to G in the C major scale. When the keypad is switched to the scales mode and the minor pentatonic scale of 25 C major is selected, PC code 99 results in MIDI code 41 corresponding to F. If the scale is switched to C major blues, the MIDI code generated by interface 12 will be 42, resulting in Gb. In the drums mode, MIDI signals are output on MIDI channel 10. Here, PC code 99 results in the generation of MIDI codes 35 and 49 which, on channel 10, generate the sound of a bass drum and a crash cymbal sounded 30 together.

Printed from Mimosa 13 Figure 5 is a block diagram of the interface 12, while Figure 6 provides a systems diagram of the combined keyboard and interface when operating in the music mode. Referring particularly to Figure 5, interface 12 is based around the operation of a dedicated microprocessor 40 that is connected to two EPROM memory chips 42 and 5 43. Chip 42 contains factory-defined data for keyboard key allocations, the conversion of PC keyboard signals to MIDI signals, and other factory-set data. Chip 43 stores data relating to user-defined preferences and can be selectively overwritten under user control. The data in each memory is conveniently arranged in the form of look-up tables, not unlike the tabulations of Figure 4.

The output of PC keyboard 14 is connected to input socket 44 and is processed by a handler circuit 46 which puts the code into a form suited to microprocessor 40. Handler circuit 46 has an output which is connected to an output socket 48 that may be connected, in turn, to keyboard port of PC 20. In normal use of the PC, signals are 15 passed from keyboard 14 directly to the PC 20 so that the keyboard functions as a conventional computer keyboard. Operation of the PC Ctrl and End keys together may be used to toggle between the MIDI and computer input modes.

On the MIDI side of interface unit 12 are a combined input/output socket 50 for 20 connection to the sound card of PC 20, a standard MIDI output 52 for sound generator 22 and a standard MIDI input socket 54 which accepts the output from a standard MIDI piano-style keyboard 18 (Figure 1). Microprocessor 40 is interfaced with these input/outputs via a MIDI converter circuit 56, a MIDI combiner circuit 58 and a MIDI driver circuit 60. In addition, a joystick input port 62 is provided for 25 connection to joystick 16, being interfaced to microprocessor 40 via an adapter circuit 64. These circuit elements are known in themselves as they are used in many MIDI devices and specialised chip sets are available for their implementation.

The system diagram of Figure 6 sets out the functional relationship of the keyboard 30 and interface from a different perspective. It indicates the MIDI channel allocations used in the example.

Printed from Mimosa 14 While one particular example of the implementation of the invention has been described, it will be appreciated by those skilled in the art that many variations and modifications may be made without departing from the scope of the invention as claimed below.

Printed from Mimosa

Claims

1 A method of converting the output of a PC keyboard having a numerical keypad into MIDI-format signals suitable for input to MIDI-compatible devices, the keyboard

5 having a plurality of control keys and the method comprising the steps of:

converting keyboard signals generated by activation of a sequence of keys in the keypad into MIDI-format signals corresponding to successive notes in a first musical scale, such that the MIDI signal for the root note of said scale is elicited from a given keypad key, and

10 upon activation of one or more of the control keys, converting keyboard signals generated by activation of the same sequence of keys in the keypad into MIDI-format signals corresponding to successive notes in a second musical scale, such that activation of said given key elicits the MIDI signal for the root note of said second scale.

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2 A method of converting the output of a PC keyboard to MIDI-format signals suitable for input into MIDI-compatible devices, the keyboard having a lefthand group of keys and a numerical keypad disposed toward on the right of the keyboard, said method comprising the steps of:

20 converting keyboard signals generated by activation of single keys in the lefthand group into MIDI-format signals corresponding to the chords of a given musical scale, and converting keyboard signals generated by activation of a sequence of keypad keys into MIDI-format signals corresponding to a sequence of notes in said scale,

25 such that-the MIDI signal for the root note of said scale is elicited from a given keypad key.
3 A method according to claim 2 characterised in that, upon activation of successive keys in the lefthand group corresponding to chords of different musical

30 keys or musical scales, activation of said given keypad after generation of each chord will elicit the root note of the musical key or scale of that chord.

Printed from Mimosa

WO 98/58363

PCT/AU98/00475

16
4 A method of converting signals output from a PC keyboard having a numeric keypad into MIDI-format signals suitable for input into MIDI-compatible devices, the method comprising the step of converting keyboard signals generated by activation of a sequence of keys of the keypad into MIDI-format signals corresponding to a

5 sequence of musical sounds in a chord of a predetermined musical key, a sequence of musical sounds in a predetermined musical scale, or a sequence of musical sounds in a predetermined group of percussion instruments.
5 A method according to claim 4 including the step of converting keyboard signals 10 generated by activation of a sequence of keys of the keypad into MIDI-format signals corresponding to a sequence of musical sounds similar to successive members of a predetermined group of percussion instruments, such that activation of a sequence of adjacent keys in the keypad is converted to a drum progression or a drum roll.

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6 A method according to claim 4 or 5 wherein the PC keyboard includes a plurality of function keys, and wherein said conversion of keyboard signals generated by activation of a sequence of keys of the keypad into MIDI-format signals corresponding to a sequence of musical sounds in a chord of a predetermined musical key comprises a first mode of operation, conversion of keyboard signals generated by 20 activation of a sequence of keys in the keypad into MIDI-format signals corresponding to a sequence of musical sounds in a predetermined musical scale comprises a second mode of operation, and conversion of keyboard signals generated by activation of a sequence of keys in the keypad into MIDI-format signals corresponding to a sequence of musical sounds in a predetermined group of percussion instruments 25 comprises a third mode of operation, said method including the step of employing keyboard signals generated by activation of one or more of the function keys to effect selection between said modes of operation.
7 A method according to any preceding claim wherein the PC keyboard has a 30 central group of symbol keys arranged in four rows of keys, the first row of keys being furthest from the user and the fourth row being closest to the user, the method including the steps of:

Printed from Mimosa

WO 98/58363

PCT/AU98/00475

17

converting keyboard signals generated by activation of keys in the first row of symbol keys into MIDI-format signals corresponding to respective tones of a first set of black piano notes that fall within at least one first octave of a piano keyboard, converting keyboard signals generated by activation of keys in the second row of 5 symbol keys into MIDI-format signals corresponding to respective tones of a first set of white piano notes that fall within said one first octave,

converting keyboard signals generated by activation of keys in the third row of symbol keys into MIDI-format signals corresponding to respective tones of a second set of black piano notes that fall within at least one second octave of a piano 10 keyboard, and converting keyboard signals generated by activation of keys in the fourth row of symbol keys into MIDI-format signals corresponding to respective tones of a second set of white piano notes that fall within said second octave.

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8 Interface means adapted to convert signals output from a PC keyboard having a numerical keypad into MIDI-format signals suitable for driving MIDI-compatible devices, said means comprising:

input means for receiving signals PC-format signals output from the keyboard when keys of the keyboard are activated,

20 output means for delivering MIDI-format output signals to the MIDI-compatible devices,

signal conversion means functionally arranged between said input and said output means, such that keyboard signals generated by activation of a sequence of keys in the keypad are converted into MIDI-format signals corresponding to a 25 sequence, of notes in a predetermined musical scale, or to a sequence of musical sounds in a predetermined group of percussion instruments.
9 Interface means according to claim 8 wherein the keyboard includes a lefthand group of keys, wherein:

30 keyboard signals generated by activation of single keys in the lefthand group are converted into MIDI-format signals corresponding to the chords of a given musical scale, and

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WO 98/58363

PCT/AU98/00475

18

keyboard signals generated by activation of a sequence of keypad keys following activation of a key of the lefthand group are converted into MIDI-format signals corresponding to a sequence of notes in the scale of the corresponding chord, such that the MIDI signal for the root note of each scale is generated from 5 activation of the same keypad key.
10 Interface means according to claim 8 or 9 wherein the PC keyboard has a central group of symbol keys arranged in four rows, said means being such that: input signals from the keyboard generated by the depression of keys in the first 10 row of symbol keys are output as MIDI-format signals corresponding to respective tones of a first set of black piano notes that fall within at least one first octave of a piano keyboard tuned to a given musical key,

input signals generated by the depression of keys in the second row of symbol keys are output as MIDI-format signals corresponding respective tones of 15 a first set of white piano notes that fall within said at least one first octave,

input signals generated by the depression of keys in the third row of symbol keys are output as MIDI-format signals corresponding respective tones of a second set of black piano notes that fall within at least one second octave of a piano keyboard tuned to said musical key, and 20 input signals generated by the depression of keys in the fourth row of symbol keys are output as MIDI-format signals corresponding respective tones of a second set of white piano notes that fall within said at least one second octave.

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