JP5320545B2 - Keyboard stroke detection device - Google Patents

Description

  The present invention relates to an apparatus for detecting a keyboard stroke for a musical instrument provided with a keyboard and provided with an elastic member (front punching) for absorbing an impact when a key is pressed.

  In order to overcome the fact that the same tone color control could not be performed with each key even at the same key pressing speed due to variations in the detection unit of each key, the key was pressed based on the change in the amount of light reaching the light receiving element constituting the detection unit. When detecting the key depth and calculating the key pressing speed from the key position data detected by pressing the key, the element variation of the light emitting element and the light receiving element is corrected, and the tone color control is performed based on the corrected data. An apparatus has been proposed (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 10-171453 (page 2-3, FIG. 1)

  However, this apparatus only considers correction of device manufacturing variations, and has the following problems. This will be described with reference to FIGS. Reference numeral 5 in FIG. 7 denotes a keyboard, which is a schematic cross-sectional view of the keyboard 5 as viewed from the side. The uppermost part shows the keyboard 5 in the complete key release position where the keyboard 5 is completely released, and the lowermost part shows the keyboard 5 in the complete key depression position where the keyboard 5 is fully depressed. A threshold value 1 (first contact) and a threshold value 2 (second contact) are set for the keyboard stroke that is the width of both positions. Usually, the threshold 1 (first contact) is set at a distance of about 45% of the keyboard stroke from the complete key release position, and the threshold 2 (second contact) is set from the complete key release position. It is set at a distance of about 75% of the keyboard stroke. The key pressing speed is obtained from the distance between the two threshold values and the time for passing through both the threshold values.

  On the other hand, FIG. 8 is an explanatory diagram of the relationship between the keystroke (key depression) strength and the keyboard stroke in a keyboard instrument provided with front punching (not shown in FIG. 8) that is an absorbing member that absorbs the keystroke impact force at the time of keystroke. It is. Here, the keyboard stroke refers to the amount of movement (distance) of the front end of the keyboard 5 relative to the performer at both the complete key release position and the complete key press position. Then, as shown in FIG. 8, it is understood that the keyboard stroke increases as S1, S2, and S3 as the keystroke strength increases. This is because the front punching is formed of an elastic member such as felt, and thus the front punching is deformed more greatly as the keying strength is higher. Therefore, since the keyboard of an acoustic piano is usually provided with front punching, the front punching is deformed according to the keystroke strength, and there is a problem that a sensor voltage corresponding to the intended keyboard stroke cannot be obtained. . As a result, there is a problem that when the threshold setting as shown in FIG. 7 is performed for an inaccurate keyboard stroke, the key pressing speed, the sound generation, and the mute timing change for each keyboard. As a result, it was difficult to accurately perform various adjustment operations at the piano installation location after the piano was sold. Such a problem cannot be solved by the conventional simple key pressing speed correction as described above.

  The present invention has been made in order to solve such a conventional problem, and an accurate keyboard stroke can be achieved for a keyboard instrument provided with front punching (an impact absorbing member at the time of keystroke) regardless of the key depression strength. It is an object of the present invention to provide an apparatus that can obtain the above.

In order to achieve the above-mentioned object, the present invention is an apparatus for detecting a keyboard stroke with respect to a musical instrument provided with a keyboard and provided with an elastic member for absorbing a shock during key depression.
A sensor unit that outputs a voltage that increases as the key depression depth increases;
When a count instruction is given, a timer unit that starts measuring operation of elapsed time (timer value) and updates the timer value at that time every time the maximum value of the output voltage from the sensor unit is updated, and
Storage means for storing a sensor voltage correction amount (V = k / T ² (k is a constant)) for the timer value (T) ;
Control means for controlling the operation of the device itself,
This control means
A key pressing start determining means for determining that the key pressing operation is started when the output voltage from the sensor unit exceeds a preset reference voltage;
Count instruction supply means for giving a count instruction to the timer unit in response to the key pressing start determination;
A key release completion determination means for determining that the key release operation has been completed when the output voltage from the sensor unit falls below the preset reference voltage;
In response to the key release completion determination, the sensor voltage correction amount (V = k / T ² (k is a constant ) corresponding to the timer value (T) held by the timer unit with reference to the storage contents of the storage means. )) , And a correction means for subtracting the grasped sensor voltage correction amount from the maximum sensor voltage value.

  When the key pressing start determining unit determines that the key pressing operation has started when the output voltage from the sensor unit exceeds a preset reference voltage, the count instruction supply unit gives a count instruction to the timer unit. When the key release completion determination unit determines that the key release operation is completed when the output voltage from the sensor unit falls below the preset reference voltage, the correction unit responds to the determination with respect to the timer value. By referring to the storage contents of the storage means storing the sensor voltage correction amount, the sensor voltage correction amount corresponding to the timer value held by the timer unit is grasped, and the maximum sensor voltage value is corrected by the grasped sensor voltage correction amount. . As a result of this correction, the sensor voltage width corresponding to the true keyboard stroke can be obtained. In other words, even with a keyboard instrument provided with an elastic member for absorbing shock when a key is pressed, the sensor voltage width corresponding to the true keyboard stroke can be obtained, so that the keyboard stroke can be obtained accurately.

  The control means may further include a key pressing speed detecting means for determining a key pressing speed in consideration of a sensor voltage width corresponding to the determined true keyboard stroke. Specifically, the key pressing speed detecting means sets a first voltage threshold value and a second voltage threshold value larger than the first voltage threshold value for the sensor voltage width, and a difference between the first voltage threshold value and the second voltage threshold value. The distance information corresponding to is divided by the time from the time when the voltage from the sensor section exceeds the first voltage threshold to the time when the voltage exceeds the second voltage threshold.

The above-described device uses a sensor unit that outputs a voltage that increases as the key depression depth increases, but a sensor that outputs a voltage that decreases as the key depression depth increases. An apparatus having the same effect can be configured using the unit. That is, a device for detecting a keyboard stroke with respect to a musical instrument provided with a keyboard and provided with an elastic member for absorbing a shock when the key is pressed, and outputs a voltage that decreases as the key pressing depth increases. When the count instruction is given, the timer unit starts measuring the elapsed time (timer value) and updates and holds the timer value at that time every time the minimum value of the output voltage from the sensor unit is updated And a storage means for storing a sensor voltage correction amount (V = k / T ² (k is a constant)) for the timer value (T) , and a control means for controlling the operation of the device itself. A key pressing start determining unit that determines that a key pressing operation has started when an output voltage from the sensor unit falls below a preset reference voltage, and in response to the key pressing start determination, instructs the timer unit to count. Give In response to the key release completion determination unit, the key release completion determination unit that determines that the key release operation is completed when the output voltage from the sensor unit exceeds the preset reference voltage, and the key release completion determination. Then, referring to the stored contents of the storage means, the sensor voltage correction amount (V = k / T ² (k is a constant)) corresponding to the timer value (T) held by the timer unit is grasped and grasped. It is also possible to provide a keyboard stroke detecting device comprising correction means for adding the sensor voltage correction amount to the minimum sensor voltage value.

  According to the present invention, even in a keyboard instrument provided with front punching, it is possible to obtain an effect that an accurate keyboard stroke can be obtained regardless of the key depression strength.

  The best mode for carrying out the present invention will be described below with reference to the drawings. In this embodiment, a description will be given of an embodiment in which the present apparatus is applied to a grand piano-type muffler piano. However, the present apparatus is provided with a keyboard and an elastic member (front punching) for absorbing an impact when the key is depressed. The present invention can be applied to other keyboard instruments, for example, a non-silent piano (including an upright type) in addition to a silent piano. If front punching is provided, it can be applied to an electronic keyboard instrument.

(Constitution)
FIG. 1 is a block diagram of a keyboard stroke detecting device according to the present invention applied to a grand piano-type silenced piano. FIG. 1 is a cross-sectional view in a direction perpendicular to the keyboard arrangement direction, for example, in a mute piano having a keyboard portion having 88 keys. The keyboard section is configured by arranging a plurality of keys from the front side to the back side in the figure. The key 5 is configured to be swingable with the balance pin 3 as a fulcrum, and a front pin 2 is provided to ensure this. The front pin 2 is a hollow disk-shaped member in plan view and uses a front pin moving hole (not shown) in the key 5 through a hollow portion of the front punching 30 which is a member that absorbs an impact at the time of keystroke. The front punching 30 is placed on the upper surface of the substrate 1. The front punching 30 is made of an elastic member such as a felt member.

  Reference numeral 20 denotes a keystroke mechanism. When the key 5 is depressed, the key striking mechanism 20 works and the hammer 21 rotates in the upward direction of the drawing to strike the string 10. At this time, the tip of the key is configured to push up the protrusion 15 to actuate the crank portion 14 to push up the metal wire 12 and release the stationary control of the damper 8 that has kept the string 10 stationary. FIG. 1 shows a state when the key is completely released. The position of the key 5 at the time of the complete key release is set as a reference position, and the distance (movement amount) that moves away from the reference position as the keyboard 5 is pressed. Is called the key depression depth. That is, if d is the key depression depth, the key depression depth d is “0” in the key release state (reference position), and the key depression depth increases as the key depression operation is performed ( In other words, “d” increases. Although not shown in FIG. 1, in the case of a mute piano, there is provided a string striking prevention mechanism for blocking the string striking operation of the string 10 of the hammer 21 of the string striking mechanism 20, and this can be activated when necessary. Has been.

  In addition, a sensor unit 100 is provided slightly on the right side of the upper surface of the substrate 1 in the drawing. In the sensor unit 100, an LED (light emitting element) (not shown) and a phototransistor (light receiving element) are arranged close to each other, and light from the LED is reflected by the back surface of the key 5 and received by the phototransistor. It has become. A voltage obtained by extracting the current flowing through the phototransistor as a voltage with a resistor is supplied as a sensor voltage to a signal processing system described later. In FIG. 1, connection lines and the like with a signal processing system described later are not shown. As shown in FIG. 2, the relationship between the key depression depth and the sensor output voltage has a positive correlation, and the sensor output voltage increases monotonously as the key depression depth d increases. ing. Therefore, the key depression depth and the sensor output voltage correspond one-to-one, and the CPU 200 described later is configured to grasp the sensor voltage and grasp the key depression depth. In this example, the sensor unit 100 is assumed to be a pre-installed type incorporated at the time of manufacturing the piano. However, the sensor unit 100 can be retrofitted after the purchase of the piano, or the piano adjustment engineer can use this sensor unit. It is also possible to adopt a configuration in which 100 is worn when performing piano adjustment.

  Next, the signal processing system will be described with reference to FIG. The output voltage signal from the sensor unit 100 is converted from analog to digital by the A / D conversion unit 215, and the CPU 200 receives it. Further, the CPU 200 includes a timer unit 202, and operates according to a program recorded in the ROM 205. At this time, the RAM 210 is used as a work area. The timer unit 202 starts a timer value measuring operation that increases from the initial value “0” when a count instruction is given from the CPU 200, and at each time the maximum value of the output voltage from the sensor unit 100 is updated. The timer value is updated and held. For example, when the output voltage from the sensor unit 100 is gradually increased in the key pressing process, the timer unit 202 updates and holds the timer value each time. On the other hand, in the key release process, the sensor output voltage usually decreases, so that the timer value is not normally updated.

Further, the ROM 205 stores a table 207 in which values of quadratic functions as shown in FIG. 4 are registered. In this table 207, sensor voltage correction amounts for timer values are registered. By the way, as a result of diligent research by the present inventors, the amount of deformation of the front punching 30 increases proportionally as the key is strongly pressed, but the amount of deformation is found to be proportional to the square of the key pressing speed. That is, it was noted that the faster the key pressing speed, the larger the deformation amount of the front punching 30. As a result, the key pressing depth becomes deeper than actual and the true sensor output voltage also increases. Here, the relationship between the function of the timer unit 202 described above, depression velocity (striking speed of the front punching 30) since it is considered to be inversely proportional to the timer value, the timer value T and the sensor output voltage correction value [Delta] V, In short, “ΔV = k / ( T × T ) ” (k is a preset constant). Accordingly, the relationship between the timer value and the correction amount ΔV as shown in FIG. 4 can be tabulated and correction can be performed. Of course, the correction processing may be performed by calculating by the equation itself to obtain the correction amount.

(Operation)
Next, the operation of the CPU 200 will be described with reference to FIGS. In FIG. 6, as shown in the left side of the figure, the key depression depth becomes deeper in the upward direction (in other words, the sensor output voltage becomes larger), while the key depression depth becomes shallower in the downward direction (in other words, The vertical axis is set so that the sensor output voltage is small), and the horizontal axis is the time. First, in step S500, if the CPU 200 determines that the sensor output voltage exceeds a reference voltage that is slightly larger than the voltage at the time of complete key release, it is determined that the key pressing operation has started. The reference voltage may be a sensor output voltage value (offset voltage) with respect to the key depression depth “0” shown in FIG. As soon as it is determined that the key pressing operation has started, the CPU 200 gives a count instruction to the timer unit 202. As a result, the timer unit 202 given the count instruction starts an operation of measuring an elapsed time (timer value) from the initial value “0”, and every time the maximum value of the output voltage from the sensor unit 100 is updated. The timer value at that time is updated and held (step S510). The time point at which the timer measurement is started is indicated by the symbol A in FIG. In the example of FIG. 6, the sensor voltage is updated monotonously with the start of key depression, so that the timer value at the peak position is held in the timer 202 (see symbol B in FIG. 6). In the vicinity of the peak position, the front punching 30 is in a deformed state.

  Then, the key release operation is started, and the key pressing depth gradually becomes shallow as a whole, and the sensor voltage decreases accordingly. As a result, in step S520, the CPU 200 determines that the key release operation is completed when the output voltage from the sensor unit 100 falls below the reference voltage (see C in FIG. 6). In step S530, in response to this determination, the CPU 200 refers to the stored contents of the table 207, grasps the sensor voltage correction amount corresponding to the maximum timer value held by the timer unit 202, and grasps this grasp. The maximum sensor voltage value is corrected by the sensor voltage correction amount (see reference symbol D in FIG. 6), and the sensor voltage width corresponding to the keyboard stroke is obtained. In the correction process in this case, the maximum sensor voltage is a voltage obtained by subtracting the sensor voltage correction value from the maximum sensor voltage. Finally, in step S540, the CPU 200 stores the sensor voltage width corresponding to the true keyboard stroke obtained by correction together with the key number (key identifier) in the RAM 210. It should be noted that the sensor voltage width obtained in step S540 can be converted into a key pressing depth width with reference to FIG. Therefore, according to the present embodiment, an accurate keyboard stroke can be obtained for a keyboard musical instrument provided with front punching, regardless of the key depression strength.

  In the above description, the sensor unit 100 that outputs a voltage that increases as the key depression depth increases is assumed. However, a voltage that decreases as the key depression depth increases. Even when the sensor unit 100 is used, an apparatus that can obtain the same effect can be realized. In this case, the processing from step S500 to step S530 in FIG. 5 may be changed so as to be adapted to the sensor unit 100 that outputs a voltage that decreases as the key depression depth increases.

(Other)
Further, since an accurate sensor voltage width corresponding to the keyboard stroke has been obtained, the CPU 200 can read out this from the RAM 210 and use it to obtain an accurate key pressing speed for the second key pressing. . That is, the CPU 200 sets a first voltage threshold and a second voltage threshold larger than this for the sensor voltage width. Then, the CPU 200 uses the distance information corresponding to the difference between the first and second voltage thresholds as the time from when the voltage from the sensor unit exceeds the first voltage threshold to when the voltage exceeds the second voltage threshold. The key pressing speed can be obtained by dividing by. The distance information corresponding to the difference between the first and second voltage thresholds described above can be obtained based on the relationship between the key depression depth and the sensor output voltage in FIG.

  Even in the case of obtaining the key pressing speed, instead of the sensor unit 100 that outputs a voltage that increases as the key pressing depth increases, a voltage that decreases as the key pressing depth increases. In this case, the CPU 200 sets a first voltage threshold value and a second voltage threshold value smaller than the first voltage threshold value for the sensor voltage width. The distance information corresponding to the difference between the two voltage thresholds is divided by the time from when the output voltage from the sensor unit 100 falls below the first voltage threshold to below the second voltage threshold to obtain the key pressing speed. What is necessary is just composition.

  Further, according to the present apparatus, it is possible not only to obtain an accurate key pressing speed in this way, but also to obtain the timing of sound generation and mute without variation for each keyboard. In addition, regarding the arrangement position of the sensor unit 100, the structure of each piano, for example, the arrangement position of the balance rail, the front rail, the key top position, and the like are taken into account, and the sensor voltage output has a positive correlation according to the key depression operation. In addition, an appropriate position where a large dynamic range can be obtained can be adopted.

  As described above, the present invention can be applied to a keyboard instrument provided with front punching to provide a suitable device.

It is explanatory drawing of a structure at the time of applying the apparatus of this invention to a grand piano type silencer piano. It is explanatory drawing which shows the relationship between key pressing depth and a sensor output voltage. It is a block diagram of a signal processing system. It is explanatory drawing of the table 207 It is explanatory drawing of operation | movement of a signal processing system. It is explanatory drawing of operation | movement of a signal processing system. It is explanatory drawing of a prior art. It is explanatory drawing of a prior art.

Explanation of symbols

1 Substrate
2 Front Pin 3 Balance Pin 5 Key 8 Damper 10 String 14 Crank Part 15 Projection Part 20 Key Tapping Mechanism 21 Hammer 30 Front Punching 100 Sensor Part 200 CPU
202 Timer section 205 ROM
207 Table 210 RAM
215 A / D converter

Claims (2)

An apparatus for detecting a keyboard stroke with respect to a musical instrument provided with a keyboard and provided with an elastic member for absorbing a shock when the key is depressed,
A sensor unit that outputs a voltage that increases as the key depression depth increases;
When a count instruction is given, a timer unit that starts measuring operation of elapsed time (timer value) and updates the timer value at that time every time the maximum value of the output voltage from the sensor unit is updated, and
Storage means for storing a sensor voltage correction amount (V = k / T ² (k is a constant)) for the timer value (T) ;
Control means for controlling the operation of the device itself,
This control means
A key pressing start determining means for determining that the key pressing operation is started when the output voltage from the sensor unit exceeds a preset reference voltage;
Count instruction supply means for giving a count instruction to the timer unit in response to the key pressing start determination;
A key release completion determination means for determining that the key release operation has been completed when the output voltage from the sensor unit falls below the preset reference voltage;
In response to the key release completion determination, the sensor voltage correction amount (V = k / T ² (k is a constant ) corresponding to the timer value (T) held by the timer unit with reference to the storage contents of the storage means. )) to grasp the, keyboard stroke detector for correction means subtracting a sensor voltage correction amount this grasped from the maximum sensor voltage value, characterized in that it comprises a. An apparatus for detecting a keyboard stroke with respect to a musical instrument provided with a keyboard and provided with an elastic member for absorbing a shock when the key is depressed,
A sensor unit that outputs a voltage that decreases as the key depression depth increases;
When a count instruction is given, a timer unit that starts measuring operation of elapsed time (timer value) and updates and holds the timer value at that time every time the minimum value of the output voltage from the sensor unit is updated,
Storage means for storing a sensor voltage correction amount (V = k / T ² (k is a constant)) for the timer value (T) ;
Control means for controlling the operation of the device itself,
This control means
A key pressing start determining means for determining that a key pressing operation is started when an output voltage from the sensor unit falls below a preset reference voltage;
Count instruction supply means for giving a count instruction to the timer unit in response to the key pressing start determination;
A key release completion determining means for determining that the key release operation is completed when the output voltage from the sensor unit exceeds the preset reference voltage;
In response to the key release completion determination, the sensor voltage correction amount (V = k / T ² (k is a constant ) corresponding to the timer value (T) held by the timer unit with reference to the storage contents of the storage means. And a correction means for adding the detected sensor voltage correction amount to the minimum sensor voltage value.

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