CA1174311A - Electrical control strip formed with a potentiometer - Google Patents
Electrical control strip formed with a potentiometerInfo
- Publication number
- CA1174311A CA1174311A CA000379340A CA379340A CA1174311A CA 1174311 A CA1174311 A CA 1174311A CA 000379340 A CA000379340 A CA 000379340A CA 379340 A CA379340 A CA 379340A CA 1174311 A CA1174311 A CA 1174311A
- Authority
- CA
- Canada
- Prior art keywords
- support
- potentiometer
- support member
- resistive
- contact member
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Landscapes
- Electrophonic Musical Instruments (AREA)
Abstract
ELECTRICAL CONTROL DEVICES
ABSTRACT OF THE DISCLOSURE
A potentiometer comprises a support member having first and second support regions and an intermediate region located therebetween, a resistive member supported on the support member at the first support region thereof and having a longitudinal dimension extending transversely of a line from the first support region to the second support region, and a resilient contact member secured to the support member at the second support region and extending over the inter-mediate region and terminating superjacent the resistive member The contact member is flexible both about axes which extend parallel to the transverse line and about axes which extend transversely of the transverse line, whereby applica-tion of pressure to the contact member at a location over the intermediate region causes the contact member to engage the resistive member and movement of the point of application of pressure perpendicular to the transverse line causes the point of engagement of the resistive member by the contact member to move along the longitudinal dimension of the resistive member.
ABSTRACT OF THE DISCLOSURE
A potentiometer comprises a support member having first and second support regions and an intermediate region located therebetween, a resistive member supported on the support member at the first support region thereof and having a longitudinal dimension extending transversely of a line from the first support region to the second support region, and a resilient contact member secured to the support member at the second support region and extending over the inter-mediate region and terminating superjacent the resistive member The contact member is flexible both about axes which extend parallel to the transverse line and about axes which extend transversely of the transverse line, whereby applica-tion of pressure to the contact member at a location over the intermediate region causes the contact member to engage the resistive member and movement of the point of application of pressure perpendicular to the transverse line causes the point of engagement of the resistive member by the contact member to move along the longitudinal dimension of the resistive member.
Description
1 ~7~31 ~
This application discloses~ improvements in and modifications o~ the inYention disclosed in my. ~.S. Patent No. 4,052,923, issued October 11, 197.7.
My U.S. Patent No. 4,052,923 discloses a frequency .control strip 5 formed by a potentiometer which comprises an elongate resistive member and a sensing electrode which can . be applied to the resistive member at a position intermediate - its ends. As shown in Figures 2 and 2A of the patent, the frequency control strip 5 comprises a metal strip 6 secured by adhesive on its underside to the upper surface of a slat 3, two lengths of spacer strip 7, for example double adhesive tape, covering the edges of the metal strip 6 but leaving the central area exposed, a resistive strip comprising a length of recording tape 8 having its edges secured to the spacer strips 7 of double adhesive tape and having its magnetic emulsion on the surface facing the metal strip 6, and a pro-tective covering 9 of electrically non-conductive rayon ribbon.
Normally, the spacer strips 7 of double adhesive tape keep the recording tape 8 spaced from the strip 6.
However, when pressure is applied to the covering 9, the recording tape 8 is pressed onto the strip 6 and establishes electrical connection therewith.
The electrical arrangement of the strip 6 and the tape 8, which constitute the active parts of a frequency-control voltage source, is illustrated in Figure 4 of the ,, 117~3~ 1 patent. Thus, the opposite ends of the tape ~ are connected, through a variable range control resistor 10 and a diode drop 33 respectively to the positive and negative poles of a DC voltage source. The metal strip 6 effectively constitutes a wiper contact which taps ofr from the tape 8 a voltage dependent upon the position along the slat 3 at which pressure is applied to the covering 9, and applies that voltage to the VCO and/or VCF of an electronic music synthe-sizer, as shown, or to the frequency-related circuitry of a musical instrument.
The recording tape actually used is Scotch No. 208, having a resistance of about 50,000 ohms/inch, and having a width of 1/4".
The potentiometer provides the advantages of a linear controller, including the capabilities of making swift and subtle changes of intonation and of producing a true vibrato (continuous fluctuating frequency).
The protective covering 9 of rayon ribbon is not essential to the invention disclosed in the patent, ~ut if no protective covering is provided the fingers of ~he musician using the frequency control strip will be in continual and/or repeated sliding contact with the back surface of the tape, moving along its length. In such a case, the back of the tape should be provided with an abrasion-resistant coating, for example comprising carbon pigment suspended in a binder.
Magnetic recording tape is relatively flimsy material, not well adapted to subjection to continual and/or repeated pressure and sliding contact under the conditions encountered in the frequency control strip described in the patent (although it is recognized that it is inherent in normal use of magnetic recording tape that it is subject to continual pressure by sliding contact with, the components of a tape recorder or playback machine). Therefore, the mag-netic recording tape should preferably have a polyester base (to resist moisture, and for good stability and mechanical characteristics), preferably of greatest standard thickness (about 1.5 mils), and with a magnetic oxide coating of ~ 1743~ 1 greatest standard oxide-thickness ~about 0.65 mils~. It is also desirable that the tape and most or all of the remaining parts of the frequency control strip should be made an easily replaceable subunit like a string of a guitar or violin.
Under such an arrangement, all or part of the frequency con-trol strip, including its three terminals and perhaps even all or part of the underlying support (the slat 3 of the patent) should be easily removed and replaced, the terminals being provided with plugs or clamps and the rest of the fre-quency control strip, and possibly also at least part of thesupport, being removable and replaceable by way of plugs, clamps or adhesive.
In order to provide an electronic musical instrument playable as a violin, viola, cello or double bass, four movable slats as described in the patent, each provided with its own frequency control strip, are arranged in parallel, on a base the size and shape of the standard ~acoustic instrument) fingerboard. The player's left hand fingers the slats as if they were strings, and since the fingering action here also controls triggering and the loudness level, the player's right hand is free for other operations, such as manipulating waveform-variation controls and/or VCA controls, filters etc.
In order to provide an electronic substitute for the strings of a guitar, electric bass or other fretted instrument, four to six slats, each provided with its own frequency control strip, are arranged in parallel on a base the size and shape of the standard (acoustic instrument) fretboard. Again, the player's left hand fingers the slats as if they were strings, and since the fingering action also controls triggering and loudness level the player's right hand is free for other operations. The function of frets can be retained by providing indicia in the standard fret positions on the protective covering or other uppermost sur-face of each movable slat. The indicia may be either purely vi~ual, such as colored or etched lines on the protective covering, or partly tactile, alternating, on the uppermost surface, both relatively wide smooth regions with narrower ~ ~7ll31 1 fret-like rough regions fo~med by scoring or grooving, for example, distributed along its length.
In order to provide an electronic instrument play-able by a keyboard player, the slat would be about 2 inches wide and the protective covering would be formed with a black and wh~te keyboard pattern. The black keys and the divisions between the white keys could be provided with a different tactile effect from the white keys themselves, as by rough surfaces, Such an instrument would have only 1~ monophonic capability. In order to provide 2-voice polyphonic capability, two such slats are placed end to end and each played by a different hand. In order to provide 4-voice polyphonic capabiltiy, an additional pair of slats, end to end, are placed slightly behind and slightly higher than the ~irst pair, so that the entire assemblage looks like a 2-manual organ keyboard.
One problem with use of the frequency control strip described in the patent is that in a keyboard instrument the control strip is controlled by application of pressure within a narrow zone defined by the portion of the width of the -resistive strip 8 which upon pressure establishes electrical contact with the metal strip 9, whereas the player of an instrument having a keyboard of standard piano-forte or professional-model organ dimensions is accustomed to applying finger-pressure within a much deeper zone, the maximum depth of which is the length of a long (white) piano key (5.75 inches), although the fingers are usually applied within a somewhat shallower zone (about 3 inches) which extends from the front edges of the long keys to slightly behind the front edges of the short (black) keys. In order to overcome this problem a resilient comb-like member is secured to the slat with the teeth extending perpendicular to the length of the slat and terminating superjacent the recording tape. If the comb is made of conductive material, it may be used in place of the metal strip 6 of the potentiometer of the patent, by omitting any protective covering over the recording tape and positioning the recording tape with its magnetic surface up-~ 17431 ~
ward facing the ~erminations of the teeth~ A protectivecovering could then be provided over the comb~ the protective covering having a printed black and white keyboard pattern.
Alternatively, the metal strip could be retained, and the comb arranged so that when the teeth engage the recording tape the tape is pressed down into contact with the metal strip, just as it is pressed down by finger pressure into contact with the metal strip in the case of the control strip described in the patent. By use of a comb of suitable width, the musician ma~ be provided with a finger-contact zone of standard depth (about 3 inches), since he can apply pressure at any point along the teeth, and the teeth transmit the pressure to the much shallower zone of the record.ing tape.
In order to retain the desirable glissando control, the teeth should be as fine as possible so as to simulate an unbroken contact surface. If glissando control is regarded as relatively unimportant, the comb may be constructed to provide only one tooth for each key, and the teeth themselves may be black or white, as required for a conventional key-board, and the black teeth could be positioned higher thanthe white teeth, in order to provide a three-dimensional key-board surface.
According to the present invention there is pro-vided a potentiometer, comprising a support member having first and second support regions and an intermediate region located therebetween, and a resistive member supported on the support member at said first support region and having a longitudinal dimension extending transversely of a line from the first support region to the second support region, characterized in that a resilient contact member is secured to the support member at said second support region in con-cantilever fashion and extends over the intermediate region and terminates superjaoent the resistive member, the contact member being flexible both about axes which extend parallel to said line and about axes which extend transversely of said line, whereby application of pressure to the contact member at a location over said intermediate region causes the contact member to bend resiliently about an axis per-pendicular to said ~ine and to engage the resisti~e member and movement of the point of application of pressure per-pendicular to said line causes the point of engagement of the resistive member by the contact member to move along the longitudinal dimension of the resistive member.
According to a second aspect of the present inven-tion there is provided a potentiometer, comprising a support member having first and second support regions and an inter-mediate region located therebetween, and resistance meanssupported on the support member at said first support regions and comprising a resistive member and a sensing electrode which are spaced apart from each other but, on application of pressure, come into contact with each other, and having a longitudinal dimension extending transversely of a line from the first support region to the second support region, characterized in that a resilient contact member is secured to the support member at said second support region and ex-tends over the intermediate region and terminates superjacent the resistance means, the contact member being flexible both about axes which extend parallel to said line and about axes which Pxtend transversely of said line, whereby application of pressure to the contact member at a location over said intermediate region causes the contact member to bend resiliently about an axis perpendicular to said line and to engage the resistance means, and movement of the point of application of pressure perpendicular to said line causes the point of engagement of the resistance means by the contact member to move along the longitudinal dimension of the re-sistance means, so that when the ends of said resistive mem-ber are connected to opposite respective poles of a voltage source a voltage may be tapped off from the resistive member by way of said sensing electrode by appl~ing pressure to the intermediate region of the contact member, the tapped-off voltage being selectively variable by varying the position along the contact member at which pressure is applied thereto.
Certain of the improvements and modifications ~ 1 7 ~
discussed above will now be described in fur~her de~ail with reference to the accompanying drawings in which:-Figure 1 shows a cross-sectional view of a device for generating a Relected voltage;
Figure 2 shows a detail of the device illustrated in Figure l;
Figure 3 shows a plan view of one component of the Figure 1 device Figure 4 shows a plan view of the device illustrated 10 in Figure l;
Figure 5 ~hows a longitudinal sectional view of a first modification of the device illustrated in Figure 1, while Figure 5A is a circuit diagram showing the electrical circuit used with the Figure 5 device;
Figure 6 shows a vertical sectional view illustrating additional components of the Figures 1 and 5 devices, while Figure 6A is an elevational view taken in the direction of the arrow VIA of Figure 6 and Figure 6B
shows the ele~trical arrangement of these additional 20 components, Figure 7 shows an end view of a second modification of the devios shown in Figure 1, while Figure 7A shows a front elevation of the device, Figure 7B shows a longitudinal sectional view, to an enlarged scale, of part of the device;
25 and Figure 7C shows a circuit diagram of this modification;
Figure 8 ~hows a longitudinal sectional view of a first modification of the Figure 7 device, while Figure 8A
is a circuit diagxam of this modification;
F~gure 9 shows a fragmentary plan view of a second 30 modification of the Figure 7 device, while Figure 9A shows a circuit diagram of this modification and, Figure 9B shows a circuit diagram of a modification of the Figure 9 de~ice;
Figure 10 shows a circuit diagram of a further modification of the Figure 7 or 9 device;
Figure 11 shows a cross sectional view of one component of one v~rsion of the device employing the Figure 10 circuit; and ~1743~ ~
Figure 12 shows a circuit diagram of a further modification of the device illustrated in Figures ~ and 9A.
The device illustrated in Figure 1 comprises a slat 3 which is mounted upon a support (not shown) in the same manner 5 as the slat 3 of the patent. A frequency control strip 5 extends along one edge of the slat 3. As illustrated ~n Figure 2, the frequency control strip comprises a metal strip 6 secured by adhesive on its underside to the upper surface of the slat 3, two lengths of spacer strip 7, for 10 example double adhesive tape, covering the edges of the metal strip 6 but leaving the central area exposed, a resietive strip comprising a length of recording kape 8 having its edges secured to the spacer strips 7 of double adhesive tape and having its magnetic emulsion on i~s 15 under surface (facing the metal strip 6), and a protective CQVering 9 of electrically non-conductive rayon ribbon.
Normally the spacer strips 7 of double adhesive tape keep the recording tape 8 spaced from the strip 6.
Howe~er, when pressure is applied to the coverlng 9, the 20 recording tape 8 is pressed onto the strip 6 and establishes electrical connection therewith. The electrical arrangement of the strip 6 and the tape 8 æe as described in the patent.
A resiliént member 34 is mounted on the slat 3 with one edge secured to the slat, along the opposite edge 25 from the frequency control strip 5, by means of screws 35.
An intermediate part 34' of the member 34 extends acro~
the slat 3, perpendicular to its length~ and slightly spaced ab~ve its upper surface. The free edge of the member 34 is bent at 34a downward and/or into a U-shape. It wiil be 30 appreciated that since the member 34 is secured to the slat along only one edge, the other edge being spaced from the slat, the member 34 is supported in cantilever fashion.
As in the case of the frequency control strip described in the patent, the recording tape is Scotch No.
35 208 having a resistance of about 50,000 ohms/inch. The width of the tape is one quarter inch. The depth of the part 34' of the member 34 is about 3 inches. The member ~17~3~ ~
_g _ 34 is flexible both about longitudinal axes extending parallel to its edges and about axes extending transverseIy of its edges. When pressure is applied to the intermediate part 34' of the member 34, the corresponding lowermost 5 point of the edge 34a moves down into engagement with the protective covering 9 and thus presses the recording tape 8 into electrical connection with the metal strip 6. Thus, the member 34 serves as a transmission device for concen-trating the effect of pressure applied at any point over a 10 reIatively deep area (the depth of the part 34') into a relatively shallow area (the width of the recording tape).
Of course, the member 34 should not be so flexible about longitudinal axes that application of pressure to the member causes the entire edge 34a to move down into engage-15 ment with the protective covering 9. As illustrated inFigure 3, the member 34 may be in the form of a comb having its back secured to the slat 3 by the screws 35 and the individual teeth 3Ç of the comb being so narrow and closely spaced that use of a single fingertip to apply pressure to 20 the comb will press the tips 36a of several adjacent teeth simultaneously against the protective covrsring 9.
The upper surface of the member 34 may be covered by a flexible protective covering 37 (which is preferably eIectrically inert), for example a plastic film, having 25 on its upper surface a smooth and rough and~or black and white pattern 38, as shown in Figure 4, similar to the pattern of black and white ke~s of a piano keyboard, and with:lines 39, printed on or scored into its surface and extending perpendicular to the length of the slat near the 30 middle of the key position, as a guide to the player showing the location of the underlying tooth which, on contacting the covering 9, produces a note of the exact or "correct"
pitch for that key, for observance of the standards of fixed-intonation tuning.
In a modification of the device illustrated in Figures 1 and 2, the frequency control strip 5 comprises only a strip of recording tape which has its back surface secured ~t~d~3~1 to the slat, so that its magnetlc coating is faclng upwards, and the moving part of the fre~u~ncy control 5trip comprls~s the member 34. In this casel the member 34 is made of conductive material and is connected in the same manner as S the metal strip 6 of the frequency control strip 5 of the patent. Of course, in the case of th1s modi~icatlon the protective covering 9 is not retained, but in order to prevent leakage currents and other perturbations when the musician presses the member 34 a protective covering is 10 required and this must be made of electrically non-conductive material, such as plastic film. The covering may bear the same type of pattern and/or lines as the protective covering 37 of the device illustrated in Figures 1, 2 and 3. As in the case of Figure 1, the member 34 may have a 15 continuous intermediate portion 34', provided that it is sufficiently resistant to bending about the axes extending longitudinally of the slat, or the member 34 may be in the form of a comb ~ith teeth 360 It is preferred that the member 34 be in the 20 form of a comb with teeth 36, rather than have a contlnuous intermediate part 34', because although sultable materials are available to produce the member 34 with a contlnuous intermadiate part 34' ~i.e~ materials are avallable with suitable resilient and flexible qualities~, the physi~al 25 properties of the member 34 depend upon the conditions under which the member was produced, and the condi~ions under which the material of the member 34 was produced, and change with time, and therefore the difference in flexible and resilient qualitles about the different a*es 30 cannot be relied upon to obtain in the future, whereas in the case of a comb it is only necessary that each tooth remain flexible about axe~ extending longitudlnally of the slat: flexibility of the member 34 about axes perpendicular to the slat is achieved by vlrtue of the member being 35 in the form of a comb, not upon the physical properties of the material from which the member is made, and 90 will not be affected by passage of time.
1 ~7431 1 In a fur~her modlfication o~ the device illustrated in Figure 1, the L`Le~UenCy control strip 5 i8 rep~aced by a series of discrete electrical contacts S' illustrated in Figure 5 which are connected to respectlve points of 5 different potential in a chain of resistors 8i, illustrated in Figure 5A, which takes the place of ~he recording tape 8 In the case of the Plgure S embodiment, the intermediate portion of the member 34 ma~ be continuous as in the case of the other described embodlments, but it is preferable 10 that the member 34 should, as illustrated~ be a comb having one tooth 36 for each of the discrete con~acts 5'0 It will be appreciated that each of the contacts 5' establishes a discrete voltage level which, when applied to a VC0, VCF or other unit whose pitch or fre~uency response 15 is affected by voltage, establishes a predetermined frequencyO Thus, the de~ice illustrated in Figure 5 i~
monophonic, and iæ especially well suited for playlng fixed-intonation music, As in the case of the device disclosed in the 20 patent, in each of the devi~es il1ustrated in Figur~s 1 to 5 the siat 3 and the base member 1 upon whicn it is supported are provided with parts for g~eratlng an electrical analog signal dependent on the po~ition of Ihe slat with respec~ to the base member, and rhe de~ice i5 25 al50 provided with means for genera~ing a prede~ermined response when the slat is moved from a null position through an initiating thresholc posikion against the bias establlshed by a tension spring and for terminating the re~ponse when the support meml,er is returned from beyond ths initiatlng 30 threshold positlon towards the null positlon through a termination threshold positlon. These additional components are illustrated in Figures 6, 6A and 6B and comprise light-emitting diodes 11 and 12, a light dependent re~istor 13, a photodiode 14 and a trigger circuit lS~ The light 35 dependent resistor 13 is one component of a T-network 13a, which comprises in addition two resistors 13D and two capacitors 13c.
~ -~7431 1 It ls a1so posslbi.e to use the princlple~ of the devices illustrated in Figures 1 to 5 to produce a pol~phonlc device. In such a dev~ce, a plurality of relatively short slats 3' forming keys are mounted side by side on a base 5 member l as shown in Flgures 7, 7A and 7B by mean~ of respective hinges 20 Each of the keys 3l is provided with its own frequency control strip Sl and pressure transmitting member 34 having a solldl~ colored protective covering 37.
above it di~playing an în tune or exact pitch indicator line.
lO Each frequency control strip 51 and pressure transmitting member 34 may be constructed as described with reference to Figures l and 2 or as described with reference to the modification in which the frequency control strip comprises only a strip of recording tape~ The output from each of 15 the metal strips 6 ~in the case of the Figure l construction) or from each of the members 35 ~in the case of the modifica-tion) is processed in the same manner as the output from the metal ~trip 6 of the patent, up to but not including the power amplifler 30 and loudspeaker 26 shown in Flgure 20 5 and 6 of the patent~ In thls polyphonic devlce, a1l the outputs from the VOC~VCF circultry 20~21 fea by metal str~ps 6 or members 34 are indlvidually attenuated by light-d~pendent re iStoLs 13 assoclated with the respective keys 3' and are then mixed together in a mixer 30a and fed 25 into a single power amplifler 30 driving a sing`le loud-speaker 26, as illustrated in ~lgure 7C, The device illustrated in Figures 7, 7A, and 7B
may be modified in the light of the teaching of Figure~ 5 to 5A to provide a monphonic instrument, as illustrated in 30 Figure 8, in which each of the frequency control strips 51 is replaced by a di~crete electrode 51' and ~he separate electrodes are connected a~ illustrated in F~gure 5A. The member 34 connected to each key 3'has a continuous intermedl-ate portion 34' and is not in the form of a comb. However, 35 in the case of Figures 7, 7A and 7B each indi~idual key 3' has its own set of components for triggering and amplitude control. The different pressure transmi~ting members 34, of ~ 1743 1 1 the keys 3' respec~iveLy, are conn2cled together to a common output which i~ ultimately connected to a VC0, VCF or other unit whose pitch or fxequency response is affected by voltage as shown in Figure 5A . Of course~ the respective 5 protective coverings provided on the keys 3' respectiveIy are solidly colored and since discrete contacts are used the coverings are not provided with in tune or exact pitch indicators as in the case of Figure 7~
The device of Fiyure 8 may also be modified to 10 provide a polyphonic devlce in which each key has a fixed intonation, rather than a variable intonation as in the case of the polyphonic device of Figures 7, 7A and 7B.
In the case of this modification the electrodes 51' are connected to respective po~ential dividers, establishing 15 discrete voltage levels for the electrodes, as shown in Figure 8A~ Each potential divider comprises a fixed resistor 45 and a variable trlmmer resistor 46 connected in series with a diode drop 33 between the positive and negative poles of a D,C~ voltage source. The different 20 pressure transmit~lng members 34 are connected to respecti~e VCO's and VC~'s as in the case of Figure 7C, and each ke~
is provided with its own set of componen~s for triggering and amplitud control.
In a development shown in Figure 9 of the device 25 illustrated in Figures 7, 7~ and 7B a single elongate member 40 of resilient material is secured on one of its two longer edges by screws to a base member 1 and is formed with cuts 42 extending perpendicular to its other long edge and dividing that part of the member 40 which pro~ects 30 from the base member 1 into a series of long and short keys 43 and 44 respectively ~n such a way that the entire member 40, viewed from above~ reqembles a piano keyboard, with the length and width of each of the keys 43 and 44 equal to those of ~he corresponding piano keys. Each of 35 the keys 43 and 44 has itS own frequency control ~trip 51 attached to its upper surface adjacent the free end of the key, and its own pressure transmis~lon member 34 ~ ~4~ 1 ~
covered by a so1idly-colored protectl~e COVeElng 37 display-ing an in tune o~ exact pltch indlcator llne 39O Each of the keys 43 and 44 carries near its free end a light-emltting diode 12 ~shown in Figure 9A9 which illuminates a photodiode 5 14. Each frequency control strip 51 and pressure transmitting mem~er 34 may be constructed as described with reference to Figures l and 2 or as described with reference to the modification in which the frequency control strip comprises only a strip of recording tape The output from each of 10 the metal strips 6 (in the case of the Figure l construction) or from each of the members 34 (in the case of the modifi-cation) is processed in the same manner as the output from the metal strip 6 of the patent, up to but not including the power amplifier 30 and loudspeaker 26 shown in Figure 15 6 of the par:ent. In this polyphonic device, all the out-puts from the VCO/VCF circuitry 20/21 fed ~ metal strips 6 or members 34 are individually attenuated by light-dependent resistors 13 associated with the respective keys 3' and are then mixed together in a mixer 30a and 20 fed into a single power amplifier 30 driving a single loud-speaker 26, as illustrated in Figure 9A~
The circuit illustrated in F~gure 9A corresponds to that illustrated in Figure 6 of the patent, but a circult corresponding to that illustrated in Figure 5 could be used instead 25 if, for example, each key carried a shutter whlch passea, on depression of the key, between two LED's ~corresponding to the LED's ll and 12 of the patent9 and an LDR and a photodiode tcorresponding to the LDR 13 and the photodiode 14 of the patent) so as to decrease the illuminatlon of the LDR and 3~ the photodiode when increaYing pressure is applied to the key.
In the case of the devlce de~cribed with referellce to Figures 9 and 9A, each key 43 and 44 has its top surface coplanar with the top surfaces of the other teeth, when not subject to dewnward pressure~ However, the entire one-piece 35 member 40 may be molded or stamped in such a manner that the top surfaces of the shorter keys 44 would, when not sub~ect to downward pressure, be coplanar with each other in ~17431 1 a plane higher ~han that of the top surfaces of the longer keys 43, thus givîng the entire member 40 the three dimensional pattern shown by the arrangement of black and white keys in a piano keyboardc The device illustrated in Figures 9 and 9A could be modified to produce a monophonic keyboard by providing each of the teeth 43 and 44 with a single electrical contact instead of a frequency control strip, connected as in the case of the contacts 5' of~ Figures 5 and 5A. As in the 10 monophonic modification of Figures 7, 7A and 7B, the member 34 of the monophonic modification of Figures 9 and 9A would have a continuous intermediate portion and would not be in the form of a comb.
The monophonic modification of Figures 9 and 9A
15 could be further modified to provide a polyphonic device having a fixed intonation for each key, rather than a variable intonation, in the manner described with reference to Figure 8A, i.e~ by using a plurality of potential dividers connected to the electrical contacts respec~ively and 20 providing each key with its ~wn set of components or triggering and ampli~ude control. In a simplified form of these polyphonic devices the contacts 34 and the discrete contacts associated therewith are repiaced by direct connections between the potential dividers and the respective 25 voltage-responsive variable frequency devices 20~21, as shown in Figure 9B.
The polyphonic devices described above allow for variable intonation from each key. A polyphonic device may be produced to provide the user with a choice between 30 variable intonation from each key and a fixed intonation from each key. In order to achieve this mod1flcation, each key is provided with a double pole, double throw switch 52, and in one po~ition of the switch the output is taken from the metal strip 6 or the member 34 (depending upon whether 35 the arrangement of the frequency control strip and the member 34 is as described with reference to Figure 1 or the modification thereof) whereas in the other position of the ~7433 1 switch the output is taken from a potential divider establishing a fixed voltage output. A suitable switching arrangement is illustrated in Figure 10 of the drawings.
As illustrated in Figure 10, the positive termi~al of a 5 D.C. voltage source is connected bo the negative pole thereof through a diode drop 33 and either a variable trimmer re-sistor 10 and the strip of tape 8 or through a fixed resistor 45 and a variable trimmer re~istor 46, depending upon the position of the switch 52, and the output i8 re-10 ceived either from the metal strip 6 or member 34 or fromthe junction point of the resi~tors 45 and 46, depending upon the position of the switch 52. The connection to the~
~unction point 47 may either be a permanent connection, as illustrated in broken line, or it may be a second movable 15 contact 48 which is placed so that it establishes electrical connection with anearby fixed metal contact 49, which is connected to the junction 47, when finger pressure i8 applie~
to the protective covering 37 on the key. In the case where the connection is made permanently to the ~unction p~int 47,
This application discloses~ improvements in and modifications o~ the inYention disclosed in my. ~.S. Patent No. 4,052,923, issued October 11, 197.7.
My U.S. Patent No. 4,052,923 discloses a frequency .control strip 5 formed by a potentiometer which comprises an elongate resistive member and a sensing electrode which can . be applied to the resistive member at a position intermediate - its ends. As shown in Figures 2 and 2A of the patent, the frequency control strip 5 comprises a metal strip 6 secured by adhesive on its underside to the upper surface of a slat 3, two lengths of spacer strip 7, for example double adhesive tape, covering the edges of the metal strip 6 but leaving the central area exposed, a resistive strip comprising a length of recording tape 8 having its edges secured to the spacer strips 7 of double adhesive tape and having its magnetic emulsion on the surface facing the metal strip 6, and a pro-tective covering 9 of electrically non-conductive rayon ribbon.
Normally, the spacer strips 7 of double adhesive tape keep the recording tape 8 spaced from the strip 6.
However, when pressure is applied to the covering 9, the recording tape 8 is pressed onto the strip 6 and establishes electrical connection therewith.
The electrical arrangement of the strip 6 and the tape 8, which constitute the active parts of a frequency-control voltage source, is illustrated in Figure 4 of the ,, 117~3~ 1 patent. Thus, the opposite ends of the tape ~ are connected, through a variable range control resistor 10 and a diode drop 33 respectively to the positive and negative poles of a DC voltage source. The metal strip 6 effectively constitutes a wiper contact which taps ofr from the tape 8 a voltage dependent upon the position along the slat 3 at which pressure is applied to the covering 9, and applies that voltage to the VCO and/or VCF of an electronic music synthe-sizer, as shown, or to the frequency-related circuitry of a musical instrument.
The recording tape actually used is Scotch No. 208, having a resistance of about 50,000 ohms/inch, and having a width of 1/4".
The potentiometer provides the advantages of a linear controller, including the capabilities of making swift and subtle changes of intonation and of producing a true vibrato (continuous fluctuating frequency).
The protective covering 9 of rayon ribbon is not essential to the invention disclosed in the patent, ~ut if no protective covering is provided the fingers of ~he musician using the frequency control strip will be in continual and/or repeated sliding contact with the back surface of the tape, moving along its length. In such a case, the back of the tape should be provided with an abrasion-resistant coating, for example comprising carbon pigment suspended in a binder.
Magnetic recording tape is relatively flimsy material, not well adapted to subjection to continual and/or repeated pressure and sliding contact under the conditions encountered in the frequency control strip described in the patent (although it is recognized that it is inherent in normal use of magnetic recording tape that it is subject to continual pressure by sliding contact with, the components of a tape recorder or playback machine). Therefore, the mag-netic recording tape should preferably have a polyester base (to resist moisture, and for good stability and mechanical characteristics), preferably of greatest standard thickness (about 1.5 mils), and with a magnetic oxide coating of ~ 1743~ 1 greatest standard oxide-thickness ~about 0.65 mils~. It is also desirable that the tape and most or all of the remaining parts of the frequency control strip should be made an easily replaceable subunit like a string of a guitar or violin.
Under such an arrangement, all or part of the frequency con-trol strip, including its three terminals and perhaps even all or part of the underlying support (the slat 3 of the patent) should be easily removed and replaced, the terminals being provided with plugs or clamps and the rest of the fre-quency control strip, and possibly also at least part of thesupport, being removable and replaceable by way of plugs, clamps or adhesive.
In order to provide an electronic musical instrument playable as a violin, viola, cello or double bass, four movable slats as described in the patent, each provided with its own frequency control strip, are arranged in parallel, on a base the size and shape of the standard ~acoustic instrument) fingerboard. The player's left hand fingers the slats as if they were strings, and since the fingering action here also controls triggering and the loudness level, the player's right hand is free for other operations, such as manipulating waveform-variation controls and/or VCA controls, filters etc.
In order to provide an electronic substitute for the strings of a guitar, electric bass or other fretted instrument, four to six slats, each provided with its own frequency control strip, are arranged in parallel on a base the size and shape of the standard (acoustic instrument) fretboard. Again, the player's left hand fingers the slats as if they were strings, and since the fingering action also controls triggering and loudness level the player's right hand is free for other operations. The function of frets can be retained by providing indicia in the standard fret positions on the protective covering or other uppermost sur-face of each movable slat. The indicia may be either purely vi~ual, such as colored or etched lines on the protective covering, or partly tactile, alternating, on the uppermost surface, both relatively wide smooth regions with narrower ~ ~7ll31 1 fret-like rough regions fo~med by scoring or grooving, for example, distributed along its length.
In order to provide an electronic instrument play-able by a keyboard player, the slat would be about 2 inches wide and the protective covering would be formed with a black and wh~te keyboard pattern. The black keys and the divisions between the white keys could be provided with a different tactile effect from the white keys themselves, as by rough surfaces, Such an instrument would have only 1~ monophonic capability. In order to provide 2-voice polyphonic capability, two such slats are placed end to end and each played by a different hand. In order to provide 4-voice polyphonic capabiltiy, an additional pair of slats, end to end, are placed slightly behind and slightly higher than the ~irst pair, so that the entire assemblage looks like a 2-manual organ keyboard.
One problem with use of the frequency control strip described in the patent is that in a keyboard instrument the control strip is controlled by application of pressure within a narrow zone defined by the portion of the width of the -resistive strip 8 which upon pressure establishes electrical contact with the metal strip 9, whereas the player of an instrument having a keyboard of standard piano-forte or professional-model organ dimensions is accustomed to applying finger-pressure within a much deeper zone, the maximum depth of which is the length of a long (white) piano key (5.75 inches), although the fingers are usually applied within a somewhat shallower zone (about 3 inches) which extends from the front edges of the long keys to slightly behind the front edges of the short (black) keys. In order to overcome this problem a resilient comb-like member is secured to the slat with the teeth extending perpendicular to the length of the slat and terminating superjacent the recording tape. If the comb is made of conductive material, it may be used in place of the metal strip 6 of the potentiometer of the patent, by omitting any protective covering over the recording tape and positioning the recording tape with its magnetic surface up-~ 17431 ~
ward facing the ~erminations of the teeth~ A protectivecovering could then be provided over the comb~ the protective covering having a printed black and white keyboard pattern.
Alternatively, the metal strip could be retained, and the comb arranged so that when the teeth engage the recording tape the tape is pressed down into contact with the metal strip, just as it is pressed down by finger pressure into contact with the metal strip in the case of the control strip described in the patent. By use of a comb of suitable width, the musician ma~ be provided with a finger-contact zone of standard depth (about 3 inches), since he can apply pressure at any point along the teeth, and the teeth transmit the pressure to the much shallower zone of the record.ing tape.
In order to retain the desirable glissando control, the teeth should be as fine as possible so as to simulate an unbroken contact surface. If glissando control is regarded as relatively unimportant, the comb may be constructed to provide only one tooth for each key, and the teeth themselves may be black or white, as required for a conventional key-board, and the black teeth could be positioned higher thanthe white teeth, in order to provide a three-dimensional key-board surface.
According to the present invention there is pro-vided a potentiometer, comprising a support member having first and second support regions and an intermediate region located therebetween, and a resistive member supported on the support member at said first support region and having a longitudinal dimension extending transversely of a line from the first support region to the second support region, characterized in that a resilient contact member is secured to the support member at said second support region in con-cantilever fashion and extends over the intermediate region and terminates superjaoent the resistive member, the contact member being flexible both about axes which extend parallel to said line and about axes which extend transversely of said line, whereby application of pressure to the contact member at a location over said intermediate region causes the contact member to bend resiliently about an axis per-pendicular to said ~ine and to engage the resisti~e member and movement of the point of application of pressure per-pendicular to said line causes the point of engagement of the resistive member by the contact member to move along the longitudinal dimension of the resistive member.
According to a second aspect of the present inven-tion there is provided a potentiometer, comprising a support member having first and second support regions and an inter-mediate region located therebetween, and resistance meanssupported on the support member at said first support regions and comprising a resistive member and a sensing electrode which are spaced apart from each other but, on application of pressure, come into contact with each other, and having a longitudinal dimension extending transversely of a line from the first support region to the second support region, characterized in that a resilient contact member is secured to the support member at said second support region and ex-tends over the intermediate region and terminates superjacent the resistance means, the contact member being flexible both about axes which extend parallel to said line and about axes which Pxtend transversely of said line, whereby application of pressure to the contact member at a location over said intermediate region causes the contact member to bend resiliently about an axis perpendicular to said line and to engage the resistance means, and movement of the point of application of pressure perpendicular to said line causes the point of engagement of the resistance means by the contact member to move along the longitudinal dimension of the re-sistance means, so that when the ends of said resistive mem-ber are connected to opposite respective poles of a voltage source a voltage may be tapped off from the resistive member by way of said sensing electrode by appl~ing pressure to the intermediate region of the contact member, the tapped-off voltage being selectively variable by varying the position along the contact member at which pressure is applied thereto.
Certain of the improvements and modifications ~ 1 7 ~
discussed above will now be described in fur~her de~ail with reference to the accompanying drawings in which:-Figure 1 shows a cross-sectional view of a device for generating a Relected voltage;
Figure 2 shows a detail of the device illustrated in Figure l;
Figure 3 shows a plan view of one component of the Figure 1 device Figure 4 shows a plan view of the device illustrated 10 in Figure l;
Figure 5 ~hows a longitudinal sectional view of a first modification of the device illustrated in Figure 1, while Figure 5A is a circuit diagram showing the electrical circuit used with the Figure 5 device;
Figure 6 shows a vertical sectional view illustrating additional components of the Figures 1 and 5 devices, while Figure 6A is an elevational view taken in the direction of the arrow VIA of Figure 6 and Figure 6B
shows the ele~trical arrangement of these additional 20 components, Figure 7 shows an end view of a second modification of the devios shown in Figure 1, while Figure 7A shows a front elevation of the device, Figure 7B shows a longitudinal sectional view, to an enlarged scale, of part of the device;
25 and Figure 7C shows a circuit diagram of this modification;
Figure 8 ~hows a longitudinal sectional view of a first modification of the Figure 7 device, while Figure 8A
is a circuit diagxam of this modification;
F~gure 9 shows a fragmentary plan view of a second 30 modification of the Figure 7 device, while Figure 9A shows a circuit diagram of this modification and, Figure 9B shows a circuit diagram of a modification of the Figure 9 de~ice;
Figure 10 shows a circuit diagram of a further modification of the Figure 7 or 9 device;
Figure 11 shows a cross sectional view of one component of one v~rsion of the device employing the Figure 10 circuit; and ~1743~ ~
Figure 12 shows a circuit diagram of a further modification of the device illustrated in Figures ~ and 9A.
The device illustrated in Figure 1 comprises a slat 3 which is mounted upon a support (not shown) in the same manner 5 as the slat 3 of the patent. A frequency control strip 5 extends along one edge of the slat 3. As illustrated ~n Figure 2, the frequency control strip comprises a metal strip 6 secured by adhesive on its underside to the upper surface of the slat 3, two lengths of spacer strip 7, for 10 example double adhesive tape, covering the edges of the metal strip 6 but leaving the central area exposed, a resietive strip comprising a length of recording kape 8 having its edges secured to the spacer strips 7 of double adhesive tape and having its magnetic emulsion on i~s 15 under surface (facing the metal strip 6), and a protective CQVering 9 of electrically non-conductive rayon ribbon.
Normally the spacer strips 7 of double adhesive tape keep the recording tape 8 spaced from the strip 6.
Howe~er, when pressure is applied to the coverlng 9, the 20 recording tape 8 is pressed onto the strip 6 and establishes electrical connection therewith. The electrical arrangement of the strip 6 and the tape 8 æe as described in the patent.
A resiliént member 34 is mounted on the slat 3 with one edge secured to the slat, along the opposite edge 25 from the frequency control strip 5, by means of screws 35.
An intermediate part 34' of the member 34 extends acro~
the slat 3, perpendicular to its length~ and slightly spaced ab~ve its upper surface. The free edge of the member 34 is bent at 34a downward and/or into a U-shape. It wiil be 30 appreciated that since the member 34 is secured to the slat along only one edge, the other edge being spaced from the slat, the member 34 is supported in cantilever fashion.
As in the case of the frequency control strip described in the patent, the recording tape is Scotch No.
35 208 having a resistance of about 50,000 ohms/inch. The width of the tape is one quarter inch. The depth of the part 34' of the member 34 is about 3 inches. The member ~17~3~ ~
_g _ 34 is flexible both about longitudinal axes extending parallel to its edges and about axes extending transverseIy of its edges. When pressure is applied to the intermediate part 34' of the member 34, the corresponding lowermost 5 point of the edge 34a moves down into engagement with the protective covering 9 and thus presses the recording tape 8 into electrical connection with the metal strip 6. Thus, the member 34 serves as a transmission device for concen-trating the effect of pressure applied at any point over a 10 reIatively deep area (the depth of the part 34') into a relatively shallow area (the width of the recording tape).
Of course, the member 34 should not be so flexible about longitudinal axes that application of pressure to the member causes the entire edge 34a to move down into engage-15 ment with the protective covering 9. As illustrated inFigure 3, the member 34 may be in the form of a comb having its back secured to the slat 3 by the screws 35 and the individual teeth 3Ç of the comb being so narrow and closely spaced that use of a single fingertip to apply pressure to 20 the comb will press the tips 36a of several adjacent teeth simultaneously against the protective covrsring 9.
The upper surface of the member 34 may be covered by a flexible protective covering 37 (which is preferably eIectrically inert), for example a plastic film, having 25 on its upper surface a smooth and rough and~or black and white pattern 38, as shown in Figure 4, similar to the pattern of black and white ke~s of a piano keyboard, and with:lines 39, printed on or scored into its surface and extending perpendicular to the length of the slat near the 30 middle of the key position, as a guide to the player showing the location of the underlying tooth which, on contacting the covering 9, produces a note of the exact or "correct"
pitch for that key, for observance of the standards of fixed-intonation tuning.
In a modification of the device illustrated in Figures 1 and 2, the frequency control strip 5 comprises only a strip of recording tape which has its back surface secured ~t~d~3~1 to the slat, so that its magnetlc coating is faclng upwards, and the moving part of the fre~u~ncy control 5trip comprls~s the member 34. In this casel the member 34 is made of conductive material and is connected in the same manner as S the metal strip 6 of the frequency control strip 5 of the patent. Of course, in the case of th1s modi~icatlon the protective covering 9 is not retained, but in order to prevent leakage currents and other perturbations when the musician presses the member 34 a protective covering is 10 required and this must be made of electrically non-conductive material, such as plastic film. The covering may bear the same type of pattern and/or lines as the protective covering 37 of the device illustrated in Figures 1, 2 and 3. As in the case of Figure 1, the member 34 may have a 15 continuous intermediate portion 34', provided that it is sufficiently resistant to bending about the axes extending longitudinally of the slat, or the member 34 may be in the form of a comb ~ith teeth 360 It is preferred that the member 34 be in the 20 form of a comb with teeth 36, rather than have a contlnuous intermediate part 34', because although sultable materials are available to produce the member 34 with a contlnuous intermadiate part 34' ~i.e~ materials are avallable with suitable resilient and flexible qualities~, the physi~al 25 properties of the member 34 depend upon the conditions under which the member was produced, and the condi~ions under which the material of the member 34 was produced, and change with time, and therefore the difference in flexible and resilient qualitles about the different a*es 30 cannot be relied upon to obtain in the future, whereas in the case of a comb it is only necessary that each tooth remain flexible about axe~ extending longitudlnally of the slat: flexibility of the member 34 about axes perpendicular to the slat is achieved by vlrtue of the member being 35 in the form of a comb, not upon the physical properties of the material from which the member is made, and 90 will not be affected by passage of time.
1 ~7431 1 In a fur~her modlfication o~ the device illustrated in Figure 1, the L`Le~UenCy control strip 5 i8 rep~aced by a series of discrete electrical contacts S' illustrated in Figure 5 which are connected to respectlve points of 5 different potential in a chain of resistors 8i, illustrated in Figure 5A, which takes the place of ~he recording tape 8 In the case of the Plgure S embodiment, the intermediate portion of the member 34 ma~ be continuous as in the case of the other described embodlments, but it is preferable 10 that the member 34 should, as illustrated~ be a comb having one tooth 36 for each of the discrete con~acts 5'0 It will be appreciated that each of the contacts 5' establishes a discrete voltage level which, when applied to a VC0, VCF or other unit whose pitch or fre~uency response 15 is affected by voltage, establishes a predetermined frequencyO Thus, the de~ice illustrated in Figure 5 i~
monophonic, and iæ especially well suited for playlng fixed-intonation music, As in the case of the device disclosed in the 20 patent, in each of the devi~es il1ustrated in Figur~s 1 to 5 the siat 3 and the base member 1 upon whicn it is supported are provided with parts for g~eratlng an electrical analog signal dependent on the po~ition of Ihe slat with respec~ to the base member, and rhe de~ice i5 25 al50 provided with means for genera~ing a prede~ermined response when the slat is moved from a null position through an initiating thresholc posikion against the bias establlshed by a tension spring and for terminating the re~ponse when the support meml,er is returned from beyond ths initiatlng 30 threshold positlon towards the null positlon through a termination threshold positlon. These additional components are illustrated in Figures 6, 6A and 6B and comprise light-emitting diodes 11 and 12, a light dependent re~istor 13, a photodiode 14 and a trigger circuit lS~ The light 35 dependent resistor 13 is one component of a T-network 13a, which comprises in addition two resistors 13D and two capacitors 13c.
~ -~7431 1 It ls a1so posslbi.e to use the princlple~ of the devices illustrated in Figures 1 to 5 to produce a pol~phonlc device. In such a dev~ce, a plurality of relatively short slats 3' forming keys are mounted side by side on a base 5 member l as shown in Flgures 7, 7A and 7B by mean~ of respective hinges 20 Each of the keys 3l is provided with its own frequency control strip Sl and pressure transmitting member 34 having a solldl~ colored protective covering 37.
above it di~playing an în tune or exact pitch indicator line.
lO Each frequency control strip 51 and pressure transmitting member 34 may be constructed as described with reference to Figures l and 2 or as described with reference to the modification in which the frequency control strip comprises only a strip of recording tape~ The output from each of 15 the metal strips 6 ~in the case of the Figure l construction) or from each of the members 35 ~in the case of the modifica-tion) is processed in the same manner as the output from the metal ~trip 6 of the patent, up to but not including the power amplifler 30 and loudspeaker 26 shown in Flgure 20 5 and 6 of the patent~ In thls polyphonic devlce, a1l the outputs from the VOC~VCF circultry 20~21 fea by metal str~ps 6 or members 34 are indlvidually attenuated by light-d~pendent re iStoLs 13 assoclated with the respective keys 3' and are then mixed together in a mixer 30a and fed 25 into a single power amplifler 30 driving a sing`le loud-speaker 26, as illustrated in ~lgure 7C, The device illustrated in Figures 7, 7A, and 7B
may be modified in the light of the teaching of Figure~ 5 to 5A to provide a monphonic instrument, as illustrated in 30 Figure 8, in which each of the frequency control strips 51 is replaced by a di~crete electrode 51' and ~he separate electrodes are connected a~ illustrated in F~gure 5A. The member 34 connected to each key 3'has a continuous intermedl-ate portion 34' and is not in the form of a comb. However, 35 in the case of Figures 7, 7A and 7B each indi~idual key 3' has its own set of components for triggering and amplitude control. The different pressure transmi~ting members 34, of ~ 1743 1 1 the keys 3' respec~iveLy, are conn2cled together to a common output which i~ ultimately connected to a VC0, VCF or other unit whose pitch or fxequency response is affected by voltage as shown in Figure 5A . Of course~ the respective 5 protective coverings provided on the keys 3' respectiveIy are solidly colored and since discrete contacts are used the coverings are not provided with in tune or exact pitch indicators as in the case of Figure 7~
The device of Fiyure 8 may also be modified to 10 provide a polyphonic devlce in which each key has a fixed intonation, rather than a variable intonation as in the case of the polyphonic device of Figures 7, 7A and 7B.
In the case of this modification the electrodes 51' are connected to respective po~ential dividers, establishing 15 discrete voltage levels for the electrodes, as shown in Figure 8A~ Each potential divider comprises a fixed resistor 45 and a variable trlmmer resistor 46 connected in series with a diode drop 33 between the positive and negative poles of a D,C~ voltage source. The different 20 pressure transmit~lng members 34 are connected to respecti~e VCO's and VC~'s as in the case of Figure 7C, and each ke~
is provided with its own set of componen~s for triggering and amplitud control.
In a development shown in Figure 9 of the device 25 illustrated in Figures 7, 7~ and 7B a single elongate member 40 of resilient material is secured on one of its two longer edges by screws to a base member 1 and is formed with cuts 42 extending perpendicular to its other long edge and dividing that part of the member 40 which pro~ects 30 from the base member 1 into a series of long and short keys 43 and 44 respectively ~n such a way that the entire member 40, viewed from above~ reqembles a piano keyboard, with the length and width of each of the keys 43 and 44 equal to those of ~he corresponding piano keys. Each of 35 the keys 43 and 44 has itS own frequency control ~trip 51 attached to its upper surface adjacent the free end of the key, and its own pressure transmis~lon member 34 ~ ~4~ 1 ~
covered by a so1idly-colored protectl~e COVeElng 37 display-ing an in tune o~ exact pltch indlcator llne 39O Each of the keys 43 and 44 carries near its free end a light-emltting diode 12 ~shown in Figure 9A9 which illuminates a photodiode 5 14. Each frequency control strip 51 and pressure transmitting mem~er 34 may be constructed as described with reference to Figures l and 2 or as described with reference to the modification in which the frequency control strip comprises only a strip of recording tape The output from each of 10 the metal strips 6 (in the case of the Figure l construction) or from each of the members 34 (in the case of the modifi-cation) is processed in the same manner as the output from the metal strip 6 of the patent, up to but not including the power amplifier 30 and loudspeaker 26 shown in Figure 15 6 of the par:ent. In this polyphonic device, all the out-puts from the VCO/VCF circuitry 20/21 fed ~ metal strips 6 or members 34 are individually attenuated by light-dependent resistors 13 associated with the respective keys 3' and are then mixed together in a mixer 30a and 20 fed into a single power amplifier 30 driving a single loud-speaker 26, as illustrated in Figure 9A~
The circuit illustrated in F~gure 9A corresponds to that illustrated in Figure 6 of the patent, but a circult corresponding to that illustrated in Figure 5 could be used instead 25 if, for example, each key carried a shutter whlch passea, on depression of the key, between two LED's ~corresponding to the LED's ll and 12 of the patent9 and an LDR and a photodiode tcorresponding to the LDR 13 and the photodiode 14 of the patent) so as to decrease the illuminatlon of the LDR and 3~ the photodiode when increaYing pressure is applied to the key.
In the case of the devlce de~cribed with referellce to Figures 9 and 9A, each key 43 and 44 has its top surface coplanar with the top surfaces of the other teeth, when not subject to dewnward pressure~ However, the entire one-piece 35 member 40 may be molded or stamped in such a manner that the top surfaces of the shorter keys 44 would, when not sub~ect to downward pressure, be coplanar with each other in ~17431 1 a plane higher ~han that of the top surfaces of the longer keys 43, thus givîng the entire member 40 the three dimensional pattern shown by the arrangement of black and white keys in a piano keyboardc The device illustrated in Figures 9 and 9A could be modified to produce a monophonic keyboard by providing each of the teeth 43 and 44 with a single electrical contact instead of a frequency control strip, connected as in the case of the contacts 5' of~ Figures 5 and 5A. As in the 10 monophonic modification of Figures 7, 7A and 7B, the member 34 of the monophonic modification of Figures 9 and 9A would have a continuous intermediate portion and would not be in the form of a comb.
The monophonic modification of Figures 9 and 9A
15 could be further modified to provide a polyphonic device having a fixed intonation for each key, rather than a variable intonation, in the manner described with reference to Figure 8A, i.e~ by using a plurality of potential dividers connected to the electrical contacts respec~ively and 20 providing each key with its ~wn set of components or triggering and ampli~ude control. In a simplified form of these polyphonic devices the contacts 34 and the discrete contacts associated therewith are repiaced by direct connections between the potential dividers and the respective 25 voltage-responsive variable frequency devices 20~21, as shown in Figure 9B.
The polyphonic devices described above allow for variable intonation from each key. A polyphonic device may be produced to provide the user with a choice between 30 variable intonation from each key and a fixed intonation from each key. In order to achieve this mod1flcation, each key is provided with a double pole, double throw switch 52, and in one po~ition of the switch the output is taken from the metal strip 6 or the member 34 (depending upon whether 35 the arrangement of the frequency control strip and the member 34 is as described with reference to Figure 1 or the modification thereof) whereas in the other position of the ~7433 1 switch the output is taken from a potential divider establishing a fixed voltage output. A suitable switching arrangement is illustrated in Figure 10 of the drawings.
As illustrated in Figure 10, the positive termi~al of a 5 D.C. voltage source is connected bo the negative pole thereof through a diode drop 33 and either a variable trimmer re-sistor 10 and the strip of tape 8 or through a fixed resistor 45 and a variable trimmer re~istor 46, depending upon the position of the switch 52, and the output i8 re-10 ceived either from the metal strip 6 or member 34 or fromthe junction point of the resi~tors 45 and 46, depending upon the position of the switch 52. The connection to the~
~unction point 47 may either be a permanent connection, as illustrated in broken line, or it may be a second movable 15 contact 48 which is placed so that it establishes electrical connection with anearby fixed metal contact 49, which is connected to the junction 47, when finger pressure i8 applie~
to the protective covering 37 on the key. In the case where the connection is made permanently to the ~unction p~int 47,
2~ and the fixed metal contact 49 and the associated movable contact 48 are omitted, the frequency control strip can be constructed in either of the two configurations described above. When the contacts 48 and 49 are employed, the fre~uency control strip is constructed in the configuration 25 illustrated in Figure 11. This mGdified form of frequency control ~trip comprises a metal strip, forming the contact 49, secured by adhesive on its under surface to the up~er ~urface of the key 3', 43 or 44, a strip of flexible metal tape, such as aluminum foil sensing tape, forming the contact 30 48 and secured at it~ under surface to the contact 49 by two strips of double adhesive tape 50 covering the edges of the contact 49 but leaving the central area exposed, a~d a strip of recording tape, forming the tape 8, having its under surface secured by adhesive to the upper surface of 35 the contact 48 and having its resistive coating on its upper surface, facing towards the pressure transmitting member 34. The pressure transmitting member 34 is covered ~17~3~ 1 ~ 17-by the protective oovermg 37- Normal~y the spacer strips 50 of double adhesive tape keep the contact 48 spaced from the contact 49, but when pressure s applied to the protective covering 37, the member 34 engages the tape 8 and the contact 5 48 is pressed onto contact with the contact 49 and establinhes electrical connection therewith.
An additional and optional feature for a polyphonic keyboard configuration would be to have a single "glissando strip" placed in the very fron of the keyboard and extending lO the full length of the latter. This "gli~sando strip"
would be one complete monophonic form of the basic unit described in the patent, including a single movable slat, tension spring, motion-sensing devices, frequency-control strip, circuitry for ~onverting an analog signal into a 15 digital signal, attenuating circuitry, etc., and optionally including a transmi~sion-comb and a protective covering over the latter.
The monophonic modifications of Figures 9 and 9A
could be further modified to provlde a polyphonic device 20 having a ixed intQnation for each key but not deriving the pertinent frequencies from a plurality of potential dividers but instead deriving th~m from connections to the output~
of electronic-organ oscillator circuitry ~a one-octave se~
of oscillators 20a, each followed by a set of frequency 25 dividers 20a'], said connections feeding first through the gating circuitry 16, 17 of my triggering circuit 15 and then through the LDR 13 in my attenuation circuit 11, 13.
See Figure 12.
It is to be understood that the invention is not 30 limited to the specific constructions shown and descri~ed, as it will be apparent to those skilled in the art that changes may be made without departing from the principles of the invention as defined in the appended claims.
An additional and optional feature for a polyphonic keyboard configuration would be to have a single "glissando strip" placed in the very fron of the keyboard and extending lO the full length of the latter. This "gli~sando strip"
would be one complete monophonic form of the basic unit described in the patent, including a single movable slat, tension spring, motion-sensing devices, frequency-control strip, circuitry for ~onverting an analog signal into a 15 digital signal, attenuating circuitry, etc., and optionally including a transmi~sion-comb and a protective covering over the latter.
The monophonic modifications of Figures 9 and 9A
could be further modified to provlde a polyphonic device 20 having a ixed intQnation for each key but not deriving the pertinent frequencies from a plurality of potential dividers but instead deriving th~m from connections to the output~
of electronic-organ oscillator circuitry ~a one-octave se~
of oscillators 20a, each followed by a set of frequency 25 dividers 20a'], said connections feeding first through the gating circuitry 16, 17 of my triggering circuit 15 and then through the LDR 13 in my attenuation circuit 11, 13.
See Figure 12.
It is to be understood that the invention is not 30 limited to the specific constructions shown and descri~ed, as it will be apparent to those skilled in the art that changes may be made without departing from the principles of the invention as defined in the appended claims.
Claims (18)
1. A potentiometer, comprising a support member having first and second support regions and an intermediate region located therebetween, a resistive member supported on the support member at said first support region and having a longitudinal dimension extending transversely of a line from the first support region to the second support region, and a resilient contact member secured to the support member at said second support region in cantilever fashion and extending over the intermediate region and terminating superjacent the resistive member, the contact member being flexible both about axes which extend parallel to said line and about axes which extend transversely of said line, whereby application of pressure to the contact member at a location over said intermediate region causes the contact member to bend resiliently about an axis per-pendicular to said line and to engage the resistive member and movement of the point of application of pressure per-pendicular to said line causes the point of engagement of the resistive member by the contact member to move along the longitudinal dimension of the resistive member.
2. A potentiometer as claimed in claim 1, wherein said resistive member comprises a strip of electrically-conductive maternal of relatively high resistance and said contact member is made of electrically-conductive material of relatively low resistance, so that when the ends of the strip are connected to opposite respective poles of a voltage source a voltage may be tapped off from the strip by way of the contact member by applying pressure to the intermediate region thereof, the tapped-off voltage being selectively variable by varying the position along the con-tact member at which pressure is applied thereto.
3. A potentiometer as claimed in claim 1 or 2, wherein said contact member is electrically-conductive and is secured to the support member at said second support region and extends over the intermediate region and terminates super-jacent the resistive member and spaced therefrom, so that when the ends of the resistive member are connected to opposite respective poles of a voltage source a voltage may be tapped off from the resistive member by way of the con-tact member by applying pressure to the intermediate region thereof, the tapped-off voltage being selectively variable by varying the position along the contact member at which pressure is applied thereto.
4. A potentiometer as claimed in claim 1 or 2, wherein the resilient contact member terminates at a position spaced from the resistive member, and application of pressure to the contact member at a location over said intermediate region causes the contact member to bend into engagement with the resistive member at a point over said first support region.
5, An electrical control device, comprising a potentiometer as claimed in claim 1, and having an elongate support member which has its longitudinal dimension extending substantially parallel to the longitudinal dimension of the resistive member, and also comprising a base member and means mounting the support member on the base member so as to be movable in one direction transversely of its length with respect to said base member upon application of pressure to the intermediate region of the contact member, and the device further comprising biasing means to bias the support member against movement away from a null position in said one direction, and position pick-up means having a first part connected to said support member and a second part connected to said base member, said parts being arranged and connected to generate an electrical analog signal de-pendent on the position of said support member with respect to said base member, and the device also being provided with means for generating a predetermined response when said support member is moved from said null position through an initiating threshold position against said biasing means and for terminating said predetermined response when said support member is returned from beyond said initiating threshold position towards said null position through a termination threshold position.
6, An electrical control device, comprising a plurality of potentiometers as claimed in claim 1, each having an elongate support member which has its longitudinal dimension extending substantially parallel to the longitudi-nal dimensions of the support members of the other potentio-meters and substantially perpendicular to the longitudinal dimension of the resistive member of the potentiometer, and the device further comprising a base member and means mounting each support member on the base member so as to be movable in one direction transversely of the length of the resistive member with respect to said base member upon application of pressure to the intermediate region of the contact member, and the device further comprising, associated with each potentiometer, biasing means to bias the support member against movement away from a null position in said one direction, position pick-up means having a first part connected to said support member and a second part connected to said base member, said parts being arranged and connected to generate an electrical analog signal dependent on the position of said support member with respect to said base member, and means for generating a predetermined response when said support member is moved from said null position through an initiating threshold position against said biasing means and for terminating said predetermined res-ponse when said support member is returned from beyond said initiating threshold position towards said null position through a termination threshold position.
7. A potentiometer, comprising a support member having first and second support regions and an intermediate region located therebetween, resistance means supported on the support member at said first support region and com-prising a resistive member and a sensing electrode which are spaced apart from each other but, on application of pressure, come into contact with each other, and having a longitudinal dimension extending transversely of a line from the first support region to the second support region, and the potentiometer also comprising a resilient contact member secured to the support member at said second support region and extending over the intermediate region and ter-minating superjacent the resistance means, the contact member being flexible both about axes which extend parallel to said line and about axes which extend transversely of said line, whereby application of pressure to the contact member at a location over said intermediate region causes the contact member to bend resiliently about an axis per-pendicular to said line and to engage the resistance means, and movement of the point of application of pressure per-pendicular to said line causes the point of engagement of the resistance means by the contact member to move along the longitudinal dimension of the resistance means, so that when the ends of said resistive member are connected to opposite respective poles of a voltage source a voltage may be tapped off from the resistive member by way of said sensing electrode by applying pressure to the intermediate region of the contact member, the tapped-off voltage being selectively variable by varying the position along the con-tact member at which pressure is applied thereto.
8. A potentiometer as claimed in claim 7, wherein the resilient contact member terminates at a position spaced from the resistance means, and application of pressure to the contact member at a location over said intermediate region causes the contact member to bend into engagement with the resistance means at a point over said first support:
region.
region.
9. A potentiometer as claimed in claim 7 or 8, wherein said resistive member comprises a strip of electrically-conductive material of relatively high resis-tance and said sensing electrode comprises a strip of electrically-conductive material of relatively low resistance, one of said strips being superjacent to but spaced from the other of said strips and being flexible so that it can be pressed into electrical contact with said other strip by pressure on the resistance means by said contact member.
10. An electrical control device, comprising a potentiometer as claimed in claim 7, and having an elongate support member which has its longitudinal dimension extending substantially parallel to the longitudinal dimension of the resistance means, and also comprising a base member and means mounting the support member on the base member so as to be movable in one direction transversely of its length with respect to said base member upon application of pressure to the intermediate region of the contact member, and the device further comprising biasing means to bias the support member against movement away from a null position in said one direction, and position pick-up means having a first part connected to said support member and a second part connected to said base member, said parts being arranged and connected to generate an electrical analog signal dependent on the position of said support member with respect to said base member, and the device also being provided with means for generating a predetermined response when said support member is moved from said null position through an initiating threshold position against said biasing means and for ter-minating said predetermined response when said support member is returned from beyond said initiating threshold position towards said null position through a termination threshold position.
11. An electrical control device, comprising a plurality of potentiometers as claimed in claim 7, each having an elongate support member which has its longitudinal dimension extending substantially parallel to the longitudi-nal dimensions of the support members of the other potentio-meters and substantially perpendicular to the longitudinal dimension of the resistance means of the potentiometer, and the device further comprising a base member and means moun-ting each support member on the base member so as to be movable in one direction transversely of the length of the resistance means with respect to said base member upon application of pressure to the intermediate region of the contact member, and the device further comprising, associated with each potentiometer, biasing means to bias the support member against movement away from a null position in said one direction, position pick-up means having a first part connected to said support member and a second part connected to said base member, said parts being arranged and connected to generate an electrical analog signal dependent on the position of said support member with respect to said base member, and means for generating a predetermined response when said support member is moved from said null position through an initiating threshold position against said bias--ing means and for terminating said predetermined response when said support member is returned from beyond said initi-ating threshold position towards said null position through a termination threshold position.
12. A potentiometer as claimed in claim 1, wherein the contact member and the resistive member are covered by a flexible protective covering which is secured to the support member.
13. A potentiometer as claimed in claim 7, wherein the contact member and the resistance means are covered by a flexible protective covering which is secured to the support member.
14, A potentiometer as claimed in claim 12 or 13, wherein the protective covering is provided on its exposed surface with a pattern of keys of a keyboard instrument.
15. A potentiometer as claimed in claim 12 or 13, wherein the protective covering is provided on its exposed surface with a pattern of keys of a keyboard instrument, said pattern being made of black and white areas.
16, A potentiometer as claimed in claim 12 or 13, wherein the protective covering is provided on its exposed surface with a pattern of keys of a keyboard instrument, said pattern being made up of smooth and rough areas.
17. A potentiometer as claimed in claim 1 or 7, wherein said contact member is constructed as a comb having a plurality of teeth extending transversely of a common support part of the comb, the comb being secured at its common support part to said second support region and the teeth of the comb extending over said intermediate region and terminating superjacent the resistive member or resistance means, as the case may be.
18. A potentiometer as claimed in claim 1 or 7, wherein said contact member is constructed as a comb having a plurality of teeth extending transversely of a common support part of the comb, the comb being secured at its common support part to said second support region and the teeth of the comb extending over said intermediate region and terminating superjacent the resistive member or resistance means, as the case may be, each tooth of the comb being bent downwardly, towards said resistive member or resistance means, at a point adjacent its end further from the common support part, said end being swept upwardly.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000379340A CA1174311A (en) | 1981-06-09 | 1981-06-09 | Electrical control strip formed with a potentiometer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000379340A CA1174311A (en) | 1981-06-09 | 1981-06-09 | Electrical control strip formed with a potentiometer |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1174311A true CA1174311A (en) | 1984-09-11 |
Family
ID=4120187
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000379340A Expired CA1174311A (en) | 1981-06-09 | 1981-06-09 | Electrical control strip formed with a potentiometer |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1174311A (en) |
-
1981
- 1981-06-09 CA CA000379340A patent/CA1174311A/en not_active Expired
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4306480A (en) | Electronic musical instrument | |
| US4748887A (en) | Electric musical string instruments and frets therefor | |
| US4858509A (en) | Electric musical string instruments | |
| US4276538A (en) | Touch switch keyboard apparatus | |
| US4630520A (en) | Guitar controller for a music synthesizer | |
| EP0042005B1 (en) | Electronic music instrument | |
| US4235141A (en) | Electronic apparatus | |
| US5140887A (en) | Stringless fingerboard synthesizer controller | |
| US3965789A (en) | Electronic musical instrument effects control | |
| US3626350A (en) | Variable resistor device for electronic musical instruments capable of playing monophonic, chord and portamento performances with resilient contact strips | |
| US4044642A (en) | Touch sensitive polyphonic musical instrument | |
| US4362934A (en) | Velocity sensing device using opto-electronic switches | |
| KR900006581B1 (en) | Touch control apparatus for electronic keyboard instrument | |
| GB2078427A (en) | Electronic musical instrument | |
| US3699492A (en) | Variable resistance device for a portamento performance on an electronic musical instrument | |
| US4951545A (en) | Electronic musical instrument | |
| US5033351A (en) | Fingerboard and neck for electronic musical instrument | |
| US4305321A (en) | Electrical control devices | |
| US5237125A (en) | Method and apparatus for measuring velocity of key motion in a keyboard operated musical instrument | |
| US3657459A (en) | Musical instrument with variable amplitude | |
| US3979990A (en) | Keyboard arrangement in electronic musical instrument | |
| US2201232A (en) | Electrical musical instrument | |
| CA1174311A (en) | Electrical control strip formed with a potentiometer | |
| JPS6155695A (en) | Electronic musical instrument | |
| US5010799A (en) | Electronic keyboard instrument with key displacement sensors |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |