Patent Application
20060185499
1. Field of the Invention
The present invention generally relates to tuners for musical instruments, and more particularly relates to an interface for an electronic tuner for musical instruments to optically display for a musical note the pitch detected and the relative intonation of the note.
2. Description of the Prior Art
One of the most basic requirements for a musician is to be sure that his or her musical instrument is “in tune”, meaning that the frequency (or pitch) of the notes produced by the instrument corresponds precisely to that of a known reference.
A correctly tuned instrument, for instance, will produce a 440 hertz (Hz) pitch when an “A” note is played. An in tune “A” note is also produced when this frequency is halved (at 220 Hz), although the A note at 220 Hz will be one octave lower than the A note at 440 Hz. Similarly, A notes of various octaves are produced at 55 Hz, 110 Hz, 880 Hz, etc.
Western music has historically been based upon dividing the range between notes an octave apart into twelve equally spaced pitches, yielding a series of twelve notes: C, C# (also known as Db), D, D# (Eb), E, F, F# (Gb), G, G# (Ab), A, A# (Bb), and B. Each of these notes has a well-defined frequency benchmark. Most instruments are capable of producing an infinite variety of pitches, however, so it is necessary to calibrate and correct the pitch of an instrument so that the notes will be properly tuned relative to these agreed-upon benchmarks.
The function of electronic tuners is to detect, via a microphone or an electrical connection to the transducer (“pick up”) of an electric instrument, the pitch of a note that is produced by an instrument. Once this sound has been detected, the electronic tuner displays the specific note that the pitch most closely corresponds to, along with an indication of how precise the pitch is relative to the correct theoretical frequency for the given note. A pitch produced by a musical instrument that is close to but higher in frequency than a known reference is considered to be “Sharp” (#). For example, an A note at 450 Hz compared to a reference A note at 440 Hz would be considered to be “Sharp,” since the frequency is high relative to the 440 Hz reference. A note at 430 Hz is “Flat”, again, since it is below the 440 Hz reference.
Note that the frequency of a note may be divided into +/−50 cents, indicating the relative degree that the note is flat or sharp; electronic tuners also typically are designed to indicate intonation +/−50 cents.
There are several known electronic tuners on the market today. These include the RT-7 100 Rack Tuner manufactured by Sabine, Inc. of Alachua, Fla., and the Boss TU-2 Chromatic Tuner manufactured by Roland Corporation of Los Angeles, California. These electronic tuners have linear segmented displays and, thus, are not compact in size. Also, such linear displays do not lend themselves well to various tuning display modes, such as a “sweep” mode and a “strobe” mode, as the illumination of the segments is not necessarily continuous at the opposite ends of the display.
It is an object of this invention to provide an interface for an electronic tuning device for a musical instrument which provides an inexpensive, compact yet easily discernible illuminated dial display which enables a user to readily and quickly determine whether a musical instrument is in tune and to quickly determine the effects of manual tuning adjustment.
The present invention is an interface for an electronic tuning device which provides a compact, portable but easily discernible display having bi-color light emitting diodes (LEDs) which are arranged in a circular pattern as an illuminated dial display. This arrangement enables a user to readily and quickly determine whether a musical instrument is in tune and to quickly determine the effects of manual tuning adjustment. The interface provides either or both of two major modes of operation, which are a sweep mode and a strobe mode, to afford a readily discernible process for the user to determine when the musical instrument has been properly tuned. The modes can be selected by a preferably combined dual function power switch and display mode selector switch. A calibration reference frequency can be easily changed by pressing a reference frequency switch.
More specifically, the present invention is directed to a display interface for an electronic tuner for a musical instrument. The circuitry of the electronic tuner receives an analog signal corresponding to a note played directly from the musical instrument, if it is an electric instrument, or from a microphone, if the instrument is acoustic. The analog signal is amplified by an audio amplifier and then passed to a voltage comparator which digitizes it. The digitized signal, having a frequency corresponding to the note played, is then provided to the input of a microprocessor or microcontroller.
The microcontroller determines the frequency of the note played from the digitized signal and compares the frequency to known reference frequencies in the microcontroller's memory, to determine whether the note played is flat or sharp. The microprocessor controls the illumination of the display interface to indicate to the user the note played and whether it is flat or sharp.
A display interface for connecting to an electronic tuner for tuning a musical instrument, such as described previously, preferably includes a plurality of spaced apart, separately illuminatable, light emitting devices situated in a continuous circular array. A cylindrically-shaped light pipe is situated in proximity to the circular array of light emitting devices. The light pipe includes radially extending slits formed therein to define individually illuminatable segments. Each segment of the light pipe is illuminatable by a respective light emitting device. The display interface further includes a disc-shaped note dial. The note dial is situated in proximity to the light pipe, and includes illuminatable indicia on a surface thereof corresponding to musical notes. The indicia is illuminatable by the light pipe for viewing by a user of the electronic tuner. The microprocessor or microcontroller of the electronic tuner is operatively coupled to the display interface and selectively illuminates the light emitting devices.
These and other objects, features and advantages of the present invention will be apparent from the following detailed description of illustrative embodiments thereof, which is to be read in connection with the accompanying drawings.
The present invention is directed to an interface for an electronic tuning device for a musical instrument which provides an inexpensive, compact yet easily discernible illuminated dial display that enables a user to readily and quickly determine whether a musical instrument is in tune and to quickly determine the effects of manual tuning adjustment.
The electronic tuning device is preferably an in-line tuner, in that it may be placed in series between the electronic musical instrument 20 and an instrument amplifier 30. When the tuner is used in this manner, an electrical cable (and mating plug) 18 from the instrument 20 is connected the audio input jack 104, and another cable (and mating plug) 19 connected to the instrument amplifier 30 is coupled to an audio output jack 106. Thus, the electric signal 14 from the instrument passes through the in-line tuner to the instrument amplifier 30, with a sample of the signal being taken by the tuner circuit 100 for measurement purposes. In a foot pedal operated embodiment of the electronic tuner, a foot pedal switch (not shown) selectively breaks the electrical connection between the musical instrument 20 and the instrument amplifier 30 so that just the electronic tuner is connected to the musical instrument, and thus the musician's efforts in tuning the instrument are not amplified and heard by others, such as an audience at a performance.
The circuit 100 of the electronic tuner further includes an audio amplifier 108 which receives the electric signal 14 and amplifies it, thereby generating amplified analog signal 14a. The amplified analog signal 14a is provided to a voltage comparator 110, which clips the amplified analog signal 14a and converts it to a digital logic electrical signal 16, so that it is compatible for operation with the remaining digital components of the tuner circuit. A microcontroller or microprocessor 112 is coupled to the voltage comparator 110 and receives the digitized electrical signal 16. The microcontroller 112 includes, either internally or externally, a storage memory 114, which stores the frequencies corresponding to twelve musical notes, e.g., the fundamental frequencies for notes A, A#/(Bb), B, C, C#/(Db), D, D#/(Eb), E, F, F#/(Gb), G and G#/(Ab). Microcontroller 112 also includes, either internally or externally, a frequency comparator 116. The microcontroller 112 determines by means of the frequency comparator 116 which of the fundamental frequencies corresponding to the musical notes stored in the storage memory 114 the electrical signal 16 most closely equals. The display interface of the present invention, in the form of an optical display, comprised preferably of a circular array of circumferentially spaced apart bi-color light emitting diodes (LEDs) 118, is connected to and driven by the microcontroller 112. Each of the LEDs 118 represents one of the fundamental frequencies of the musical notes mentioned previously. The tuner circuit 100 also includes a display mode selector switch 120 and a reference pitch selector switch 122, each of which is operatively coupled to the microcontroller 112. The function and operation of these switches 120 and 122 will be discussed in greater detail.
The exploded front and rear isometric views of a preferred form of an in-line electronic tuner 300 shown in
A cylindrically-shaped light pipe 308, having radially extending slits 310, 311, formed in its front surface 313 and rear surface 315, respectively, to define twelve individually illuminatable segments 312 (see also
The disc-shaped note dial 218 is situated concentrically over the front surface 313 of the light pipe 308. The note dial 218 has a smaller diameter than that of the light pipe so that only the outer portions of segments 312 not blocked by the note dial are viewable to the user. As mentioned previously, the note dial 218 has imprinted on the surface thereof indicia in the form of the twelve musical notes 224 of one octave. The note dial is preferably opaque, except for the note indicia 224. Each note indicia 224 is situated in alignment with one corresponding segment 312 of the light pipe 308 so that the note indicia 224 appears as being backlit and readable by a user when a corresponding LED 118 illuminates.
Each of the light pipe 308 and the note dial 218 has formed centrally through the thickness thereof an opening 316, 318, respectively, to receive the pushbutton cap 306 of switch 120. The pushbutton cap 306 includes a radially extending flange 322 so that it is held captive within the tuner housing 302 by the light pipe 308 and note dial 218, but moveable within the openings 316, 318 so that it may be pressed by a user to activate switch 120.
The note dial 218 is aligned with an opening 324 formed in the front half 302a of the housing 302. The diameter of the opening 324 is slightly smaller than that of the note dial 218 so that the note dial 218 is held captive within the interior chamber 303 of the housing 302.
The back half 302b of the housing 302 has a removable cap 326 mounted thereon which houses a disc or watch battery 328. Edge and surface contacts 330a, 330b engage the opposite poles of the battery 328 to provide power to the tuner circuit 100. The microphone 102, for acoustic operation, and the reference pitch selector switch 122 are mounted on the printed circuit board 304, as shown in
As noted previously, preferably, the display mode selector switch 120 functions also as a power switch. The display mode selector switch 120 enables the user to select by pressing the switch in a consecutive manner a sweep mode, a strobe mode, and a power off mode of operation.
Referring now to
More specifically, when the mode switch 120 is pressed once, the tuner 300 preferably goes into the sweep mode of operation. This sweep mode is indicated to the user by the microcontroller 112 causing adjacent LEDs 118 to sequentially illuminate in red partially about the note dial 218, alternately on each side of the note A, LED 118(12) (illuminated in green), a few times, in a sweeping fashion. The LED 118(12) associated with the note played lights up in green. If the note played is flat, a red LED, such as LED 118(7), 118(8), 118(9), 118(10) or 118(11), counter-clockwise of the green note LED 118(12), will light. If the note played is sharp, a red LED, such as LED 118(5), 118(4), 118(3), 118(2) or 118(1), clockwise of the green note LED 118(12), will light. The particular red LED 118 that lights (i.e., how far clockwise or counter-clockwise from the green LED) indicates proportionally how flat or sharp the note is. The user tunes the instrument so that the red illuminated LED moves toward the green LED. When only the green LED remains lit, the musical instrument is in tune.
Again referring to
The microcontroller 112 also illuminates one of the plurality of LEDs 118(5), (4), (3), (2) (1), (11), (10), (9), (8), or (7), extending from the 5 o'clock to 12 o'clock (sharp 50 cents) and 7 o'clock to 12 o'clock (flat 50 cents) positions, which are the angular extents of the LEDs that may be lit for tuning the note A, to illuminate in another color, preferably red, with the microcontroller 112 selecting the one of the plurality of LEDs 118(5), (4), (3), (2) (1) or LEDs 118(11), (10), (9), (8), (7), to represent the intonation, i.e., whether the frequency of the note played is flat or sharp. In particular, the microcontroller 112 selects one of the plurality of LEDs (11), (10), (9), (8), or (7), disposed counter-clockwise to the reference musical note A, to represent the played note as being flat, and the microcontroller 112 selects one of the plurality of LEDs 118(5), (4), (3), (2) (1), disposed clockwise to the reference musical note A, to represent the played note as being sharp.
The microcontroller 112 illuminates the one of the plurality of LEDs 118(5), (4), (3), (2) (1), or LEDs 118(11), (10), (9), (8), or (7), to represent proportionally the difference in the frequency of the played note and the frequency of the reference musical note 224(12). As the user tunes the instrument 10 or 20, the microcontroller 112 will illuminate other LEDs 118 in red that are circumferentially closer to or farther from the illuminated green reference note LED 118(12), depending on how out of tune the musical instrument is.
As a result, each of the LEDs 118(1) through (11) represents a different arcuate distance from the illuminated reference note LED (in green) proportional to a sweep angle Θ with respect to the 12 o'clock position, the red reference LED 118(12) for note A, which is at 0°. That is, the 1 o'clock position represents a sweep angle Θ of +30°, the 2 o'clock position is +60°, the 3 o'clock position is +90°, and so on, with the 12 o'clock position being at 0°. Therefore, the LEDs 118(1) to (11) illuminate at different angular positions on the note dial 218 in accordance with the difference in frequency of the reference note (in this case, A) and the frequency of the played note.
Note that in the example given above for tuning musical note A, the LED 118(6) situated at the 6 o'clock position, corresponding to D #/Eb is never illuminated. The purpose of not illuminating the LED 118(6) diametrically opposite the reference note LED 118(12) is to provide a clear demarcation between those red LEDs 118(7), 118(8), 118(9), 118(10) and 118(11) situated counter-clockwise of the green reference note LED 118(12), which signify that the played note is flat, and those red LEDs 118(1), 118(2), 118(3), 118(4) and 118(5) situated clockwise of the green reference note LED, which signify that the played note is sharp.
As illustrated by
As before, the microcontroller 112 illuminates in red one of the plurality of LEDs 118(4), (3), (2) (1), (12) or LEDs 118(10), (9), (8), (7), (6) to represent proportionally the difference between the frequency of the played note and the frequency of the reference musical note (G#/Ab), corresponding to LED 118(11), illuminated in green (G).
As illustrated by
It should be noted that the microprocessor 112 can pulse width modulate the illumination of adjacent red LEDs 118 to show a smooth movement of the pitch of the played note as the musical instrument is being tuned. Thus, only one green LED 118, signifying the reference note 224, is illuminated at any one time, but two adjacent red LEDs 118, signify how sharp or flat the played note is, may be pulse width modulated to at least partially illuminate together to provide a smoothly varying display.
When the user presses the mode pushbutton switch 120 a second time, the electronic tuner 300 enters the strobe mode of operation. The LEDs 118 illuminate sequentially in red around the note dial 218 a few times to indicate to the user that the tuner 300 is in the strobe mode.
In the strobe mode of operation, the LED 118 corresponding to the note played lights up in one color, for example, green. The other LEDs 118 sequentially illuminate in a different color, for example, red, in either a counter-clockwise or clockwise direction about the note dial 218. Both the direction and speed of the illuminating red LEDs 118 provide information to the user as to how out of tune the instrument is. When the red LEDs 118 illuminate sequentially in a counter-clockwise direction, this indicates that the played note is flat compared to the reference note 224. When the red LEDs 118 sequentially illuminate in a clockwise direction, this indicates to the user that the played note is sharp compared to the reference note 224. The angular velocity or speed at which the red LEDs 118 sequentially illuminate is proportional to how sharp or flat the played note is. As the instrument 10 or 20 is tuned so that the frequency of the played note approaches the frequency of the reference note 224, the angular velocity or speed at which the red LEDs 118 sequentially illuminate decreases and then stops, indicating that the note is in tune.
In the strobe mode of operation, if the frequency of the played note is less than that of the reference note A such that the played note is flat, the microcontroller 112 illuminates the LEDs 118(1) through (11) sequentially in a counter-clockwise direction about the note dial 218 and in a different color, such as red. If the frequency of the played note is greater than that of the reference note A such that the played note is sharp, the microcontroller 112 illuminates sequentially in red the LEDs 118(1) through (11) in a clockwise direction about the note dial. The microcontroller 112 causes the LEDs 118(1) to (11) to illuminate and extinguish sequentially around the note dial 218 at an angular velocity ω.
However, the greater the deviation between the frequency of the played note and the frequency of the reference note 224, in this example, note A, the greater is the effective angular velocity ω of the sequential illumination of the red LEDs 118. As the user tunes the instrument 10 or 20 such that the frequency of the played note approaches the frequency of the reference note 224, the effective angular velocity ω of the sequential illumination decreases.
For the example illustrated in
As illustrated in
To indicate to the user that the tuner is powering down, and as further illustrated in
Returning again to the exploded views of the in-line electronic tuner shown in
The microcontroller 112 is preferably a general purpose 8 bit microcontroller having Part No. S3C9428, manufactured by Samsung Electronics Co. Ltd. of Seoul, Korea, and which selectively illuminates the LEDs 118 of the display interface.
The operational flowchart for the microcontroller 112 for operation of the tuner in the sweep mode is shown in
If a signal has been detected, the microcontroller lights the closest green LED corresponding with the detected note, within +/−50 cents (Block 403). For example, if a note C were detected, sharp by 30 cents, the C green LED would be lit.
The microcontroller 112 further determines if the note is sharp (Block 404). If so, then the microcontroller in a number of operational steps shown by Blocks 405, 406 and 407 in
A simplistic solution would be to light one of the four red LEDs clockwise of the green LED as a function of the error, dividing the 50 cent error band into four sub-bands of 12.5 cents apiece. Such operation is functional but not subjectively pleasing to the user, as the steps are too coarse.
As shown by Block 405, the microcontroller 112 computes the error, X, in cents, a positive value from 1 to 50 cents for a sharp deviation. The microcontroller 112 then computes a fine step, S, from the error, X, resulting in a value of S ranging from 1 to 16 (Block 406).
Then, and as shown in Block 407, the microcontroller takes the step, S, and pulse width modulages (PWM) the four red LEDs clockwise of the green LED. As the step varies from 1 to 16, LEDs successively further away from the green LED are lit. The following table details the preferred PWM duty cycle (as a percentage, 100%=LED fully lit, 0%=LED off) for each LED as a function of the step, S. Note that “LED 1” is physically next to the green LED and “LED 4” is the furthest from the green LED.
This PWM mechanism results in a smooth variation in intensity of the red LEDs.
If the note is not sharp as determined by the microcontroller 112 in the step shown in Block 404, then the microcontroller examines the note for a flat condition (Block 408). If this is the case, then the microcontroller 112, in steps exemplified by Blocks 409, 410 and 411 in
The cents error is a negative value, as computed by the microcontroller in the step shown by Block 409, since the note is flat. The microcontroller computes a step value, S, ranging from 1 to 16 (Block 410). The microcontroller 112 then uses the table shown previously to PWM LEDs, only this time on the counterclockwise side of the lit green LED, showing a smoothly varying indication of the flatness of the note, as shown by Block 411.
If the microcontroller 112, in Block 408, determines that the note is not flat, then the program flow moves back to the earlier step of Block 401, leaving the green LED lit, indicating that the note is in tune.
The operational flowchart for the microcontroller 112 for operation of the tuner in the strobe mode is shown in
The LED index R has values from 0 to 47. The twelve red LEDs are pulse width modulated in four levels each, for a resulting total of 48 intensity states, one for each value of R.
If a signal has been detected, the microcontroller lights the closest green LED corresponding with the detected note, within +/−50 cents (Block 423). For example, if a note C were detected, sharp by 30 cents, the C green LED would be lit.
The microcontroller 112 further determines if the note is sharp (Block 424). If so, then the microcontroller in a number of operational steps shown by Blocks 425, 426 and 427 in
As shown by Block 425, the microcontroller 112 computes the error, X, in cents, a positive value from 1 to 50 cents for a sharp deviation. The microcontroller 112 then performs a time delay of value T, computed as inversely proportional to the error, X (Block 426). This delay serves to set the rotational period of the red LED indication. The constant K in Block 426 would typically take on a value of 0.04. With this value of K and 48 total steps around the circle of the red LED indication, one cent error (X=1) results in a rotational period of about two seconds. Higher error values, X, result in proportionately faster rotational periods by reducing the delay, T.
As shown in Block 427, the microcontroller 112 adds one to LED index R, modulo 48, then and pulse width modulates the red LEDs as indexed by R. For adjacent red LEDs, an overlapping PWM format is used as with the sweep mode in the table above. Thus, as R varies from 0 to 47, a red indication moves clockwise, smoothly and circularly around the display, in much smoother a fashion than would be had if the twelve LEDs were lit in successive twelve steps.
If the note is not sharp as determined by the microcontroller 112 in the step shown in Block 424, then the microcontroller examines the note for a flat condition (Block 428). If this is the case, then the microcontroller 112, in steps exemplified by Blocks 429, 430 and 431 in
The cents error is a negative value, as computed by the microcontroller in the step shown by Block 429, since the note is flat. The microcontroller, in the step shown in Block 430, performs a delay with identical constant of proportionality K as in Block 426.
The microcontroller 112 subtracts one from LED index R, modulo 48, then and pulse width modulates the red LEDs as indexed by R (Block 431). For adjacent red LEDs, an overlapping PWM format is used as with the sweep mode in the table shown previously. Thus, as R varies from 0 to 47, a red indication moves counterclockwise, smoothly and circularly around the display.
If the microcontroller, in Block 428, determines that the note is not flat, then the program flow moves back to the earlier step of Block 421, leaving the green LED lit, and leaving the last red LED indication unchanged and unmoving, indicating that the note is in tune.
The operational flowchart for the microcontroller 112 for operation of the tuner in the reference frequency selection mode is shown in
The microcontroller 112 also starts a timer of duration 2 seconds (Block 422).
The microcontroller, in the step shown in Block 443, tests whether the timeout has expired. If so, the microcontroller saves the newly selected (or possibly the previous value of the) reference frequency for future use in tuning operations (Block 444). If the timeout has not expired, the microcontroller detects if further presses of the switch occur (Block 445).
If the switch is pressed, the microcontroller in the step shown in Block 446 of
There are several variations and modifications of the display interface described previously that are envisioned to be within the scope of the present invention. For example, one variation is where the light pipe 308 is omitted, and the light emitting devices 118 themselves situated in a spaced apart, circular manner may function in the same manner as segments 312 by selectively lighting to advise the user whether his instrument is in tune. The light given off by each light emitting device 118 may be sufficient to also directly illuminate the corresponding note indicia on note dial 218, or a second array of separate light emitting devices situated in alignment with respective note indicia on note dial 218 may be used to directly illuminate the note indicia.
A further alternative embodiment of the display interface is shown in
More specifically, the display interface in this alternative configuration includes an outer circular array of spaced apart, light emitting devices 118, such as light emitting diodes (LEDs) mounted on a round printed circuit board 350. In this embodiment, the printed circuit board 350 may include an inner circular array of LEDs 352, concentric to the outer LED array 118, to illuminate silk-screened indicia on the lens 392 of the tuner to advise the user as to what mode the tuner is operating in, e.g., “SWEEP”, “STROBE”, “COPY”, “FREQ” (frequency), “TEMPO”, “BPM” (beats per minute), and others. The printed circuit board 350 also has preferably mounted on it, among other circuitry of the electronic tuner, a plurality of sub-miniature light emitting devices 354, such as LEDs, particularly arranged on the printed circuit board as a four digit, 10 segment per digit display 356, with additional LEDs to provide decimal points 358 and a colon 360 for the display 356, for displaying the musical note played (e.g., C, C#, D, D#, etc.), as well as different operational modes, for example, as a metronome. The LEDs 118, 352 of the outer and inner circular array may be part no. SML-LXL1206XC-TR, manufactured by Lumex, Inc. of Palatine, Ill., or an equivalent thereof. The sub-miniature LEDs 354 for illuminating the four digit display 356 may be part no. SML-LXF0603XC-TR, also manufactured by Lumex, Inc., or an equivalent thereof.
A display cover 362 is situated adjacent to the printed circuit board 350. The display cover 362 acts essentially as a form for receiving a light diffusing resin 384, as will be explained in greater detail. The display cover 362 is preferably circular in overall shape, and includes an outer circumferential wall 364 and at least a first inner circular wall 366 concentrically situated within and disposed radially inwardly of the outer circumferential wall 364. A plurality of spaced apart first dividing walls 368 extending radially between the outer circumferential wall 364 and the first inner circular wall 366 divide the space between the outer wall 364 and the first inner wall 366 into a plurality of circumferentially arranged, arcuate first segments 370, preferably 12 in all. Each segment is open with a first open end 372 on the inner axial face 374 of the display cover, which faces the printed circuit board 350, and is aligned with a respective LED 118 on the printed circuit board, so that a respective LED 118 is received by one corresponding segment 370 of the display cover 362, which permits the display cover to be situated closely to the surface of the printed circuit board 350 on which the LEDs 118, 352, 354 are mounted. These first segments 370 function similarly to segments 312 of the first embodiment of the display interface shown in
The display cover 362 may further include a second inner circular wall 376 concentrically situated within and disposed radially inwardly of the first inner circular wall 366. A plurality of spaced apart second dividing walls 378 extending radially between the first and second inner walls 366, 376 divide the space between the first and second inner walls into a plurality of arcuate second segments 380, preferably 11 in all. Like the first segments 370, each of the second segments 380 is open on the inner axial face 374 of the display cover, and is aligned with a respective LED 352 of the inner row of LEDs that display the tuner mode so that a respective LED 352 is received by one corresponding second segment 380 of the display cover.
The display cover 362 also has a plurality of openings 382 formed through its thickness. The openings 382 are situated in a similar arrangement to that of the sub-miniature LEDs 354 to define the segments of the four digit, ten segment per digit display 356, and the decimal points 358 and colon 360 of the display. The openings 382 are arranged to be aligned with respective ones of the sub-miniature LEDs 354 on the printed circuit board 350 so that a respective sub-miniature LED 354 is received by one corresponding opening 382 of the display cover.
After the printed circuit board 350 is fitted onto the display cover 362, preferably closely within the confines of the outer circumferential wall 364 of the cover, a light transmissive, optical resin 384 is poured into the first segments 370, second segments 380 and openings 382 formed through the display cover, each of which is also open with second open end 386 on the opposite outer axial face 388 of the display cover, through which open ends 386 the resin is poured, and the resin-filled display cover is baked to allow the resin to cure. A suitable optical resin 384 for use with the display interface of the present invention is a Hysol Epoxy mixture (95% OS1600 and 5% AC7088), manufactured by Henkel Technologies of Dusseldorf, Germany, or an equivalent thereof. The solidified resin 384 forms a light diffuser 390 and is shown by way of example in
A lens 392, preferably formed of an optically clear polycarbonate, which transmits light therethrough, is situated adjacent to the outer axial face 388 of the display cover 362. The lens 392 includes silk-screened artwork 394 positioned over and in alignment with the second segments 380 of the display cover 362 and corresponding LEDs 352 of the inner circular array of LEDs. The artwork 394, when illuminated, display for the user the particular operational mode in which the electronic tuner is currently functioning, as described previously (e.g., “SWEEP”, “STROBE”, “COPY”, etc.). Light emitted by the outer circular array of LEDs 118, which are particularly used in the sweep and strobe modes and which selectively illuminate to light the outer, first segments 370 of the display cover, through the light diffuser 390, is viewable through the lens 392 within a circular clear band 394 defined by and between the outer circumferential edge 396 of the lens and/or a silk-screened ring positioned at the edge 396 and a radially inwardly and concentrically disposed silk-screened ring 398. The clear band 394 may further be defined as a protruding portion 400 of the front face 402 of the lens.
It should be noted that the outer circular array of LEDs 118, the inner circular array of LEDs 352, and the sub-miniature LEDs 354 may function independently of one another to selectively illuminate the first segments 370, or the second segments 380 or the four digit display 356, without necessarily illuminating any other of the segments or four digit display.
The embodiment of the display interface shown in
More specifically, in the strobe mode of operation, the closest reference note to the played note recognized by the circuit of the electronic tuner is displayed on the four digit display 356 or another alphanumeric display (not shown). The outer first segments 370 are rotationally sequentially illuminated and extinguished in one color, for example, red, so that the illuminated segments appear to race around the circumference of the lens 392 in either a clockwise direction, if the played musical note is determined by the circuit of the electronic tuner to be sharp with respect to the recognized reference note, and in a counter-clockwise direction, if the played note is determined to be flat. Also, the angular velocity ω of the sequential illumination of the segments 370 is proportional to the deviation in frequency between the played note and the reference note so that, as the musician tunes the instrument closer to the reference note, the speed at which the lighted segments 370 appear to race around the face of the lens 392 slows. When the musical instrument is in tune, such that the frequency of the played note is substantially equal to that of the reference note, the lighted red segments 370 appear to stop moving, and preferably are extinguished, and the segment 370 at the 12 o'clock position (such as the segment 312 illuminated by LED 118(12) in
In the sweep mode of operation, again the closest reference note to the played note recognized by the circuit of the electronic tuner is displayed on the four digit display 356 or another alphanumeric display. A particular outer first segment 370 is illuminated in one color, for example, red, to show the relative difference in frequency between the played note and the reference note. The angular position of the illuminated segment 370 from a chosen segment, for example, the segment at the 12 o'clock position, which acts as a reference point on the display interface, indicates to the musician the relative deviation in frequency of the played note from that of the reference note. A segment 370 positioned clockwise of the 12 o'clock segment, for example, those that are illuminated by LEDs 118(1), 118(2), 118(3), 118(4) and 118(5), as shown in
As the instrument is being tuned to the reference note in the sweep mode, the segments 370 closer to the 12 o'clock segment will be sequentially illuminated, while the segments farther away will be sequentially unlighted, to show the musician that the frequency of the played note is approaching the frequency of the reference note. If the musician mistakenly detunes the instrument, the opposite response is displayed on the display interface the segments 370 farther away from the 12 o'clock segment will illuminate and those segments closer to the 12 o'clock segment will be unlighted, showing that the played note is being tuned sharper or flatter from the reference note.
When the musical instrument is in tune with respect to a particular played note, where the frequency of the played note substantially equals that of the reference note, all of the segments except for the segment at the 12 o'clock position are unlighted, and the segment at the 12 o'clock position is illuminated, preferably in a different color, for example, green.
With the foot operated electronic tuner in the sweep mode, the relative deviation in frequency between a played note and a reference note is preferably always displayed by the angular distance from an illuminated segment relative to the segment at the 12 o'clock position, no matter what the played or reference note is, that is, all displays of the played note being flat or sharp are made relative to the 12 o'clock segment, or some other chosen segment about the face of lens 392 which acts as a reference point to display the relative difference in frequency between the played note and the reference note.
Also, in the same or similar manner to the operation of the aforementioned electronic tuner in the strobe mode, when the musical instrument is in tune with respect to a particular note, and when the tuner is operating in the sweep mode, the musician may be advised of this by illuminating the 12 o'clock segment in a different color, such as green, or in the same color, such as red, by illuminating a segment 370 other than that disposed at the 12 o'clock position, by illuminating more than just one segment 370, by flashing one or more segments 370, or by providing an indication on the four digit display 356 or other alphanumeric display.
As may be realized from the foregoing description, a display interface for an electronic tuner provides a compact, inexpensive and easily discernible display having bi-color LEDs 118 which are arranged in a preferably circular array as an illuminated dial display. This arrangement enables a user to readily determine whether a musical instrument is in tune and to quickly determine the effects of manual tuning adjustment. The display interface provides the user with two major modes of operation, which are a sweep mode and a strobe mode, for the user to determine when his musical instrument has been properly tuned. The calibration reference frequency used in the electronic tuner can be easily selected by the user. The circular array of LEDs illuminatable in different colors on the display interface provides a user friendly, continuous display of sequentially illuminatable musical notes and arcuate segments in a compact form that are easily viewable by the user.
It can be further seen from the foregoing description that the light emitting devices can be preferably situated in any number of various continuous, closed loop arrangements, and need not be arranged circularly. The light emitting devices may be arranged in an oblong loop or polygonal loop so that the light emitting devices may appear to race around the loop when sequentially illuminated in the strobe mode of tuner operation. The light pipe 308 and the note dial 218, if such are included, of the first embodiment shown in
It should be further realized that a light pipe is not a necessary element of the display interface of the present invention. It may be desirable to use the structure of the embodiment of the display interface shown in
Although illustrative embodiments of the present invention have been described herein with reference to the accompanying drawings, it is to be understood that the invention is not limited to those precise embodiments, and that various other changes and modifications may be effected therein by one skilled in the art without departing from the scope or spirit of the invention.
This application is related to U.S. provisional patent application Ser. No. 60/645,671, filed on Jan. 21, 2005, and entitled “Optical Display Interface For Electronic Tuner For Musical Instruments”, the disclosure of which is incorporated herein by reference. This application claims the benefit of priority under 35 U.S.C. 119 to the aforementioned related provisional application.
| Number | Date | Country | |
|---|---|---|---|
| 60645671 | Jan 2005 | US |
