JPH08433U - Keyboard sensor - Google Patents

Abstract

(57) [Abstract] [Purpose] To improve the sensing accuracy of the keyboard sensor used in the automatic playing piano. [Structure] N (N = 2 in the illustrated example) photocouplers 31 and 33 are provided along the longitudinal direction of the key 7. In addition, an encoder plate 29 that moves up and down in association with the key 7 and has a light transmitting portion of a predetermined pattern is provided. With these, the key pressing depth of the key 7 is detected with an accuracy of "2 ^N ".

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a keyboard sensor suitable for use in an automatic playing piano.

[0002]

[Prior art]

 Some conventional automatic performance pianos detect the speed of the hammer during performance recording. An example thereof is shown in FIG. In this figure, this automatic playing piano has a plurality of keys 101, a key mechanism 107 that drives a hammer 103 and a damper 105 based on the movement of the keys 101, and a string 109 that is struck by the hammer 103. The controller 113 is built in the piano main body. The controller 113 was connected to a plurality of sensors 115 arranged on the orbit of the hammer 103 and a solenoid 117 for applying a force to the key 101.

The automatic playing piano having such a structure functions in a recording mode and a reproducing mode. In the recording mode, when the hammer 103 strikes a string by the player's key operation, the movement of the hammer 103 is arranged on its trajectory. The hammering force of the hammer 103 is estimated by detecting the rotational speed of the hammer 103 on the basis of the detection results of the plurality of sensors 115. When the string striking force of the hammer 103 is estimated in this way, this string striking force is held in the memory of the controller 113 together with key information for identifying the operated key 101 as string striking information, and the performance ends. The above operation is repeated until.

Next, when the automatic playing piano is set to the reproduction mode, the controller 113 identifies the key 101 to be driven based on the key information and excites the solenoid 117 provided corresponding to the key 101. Then, a predetermined force is applied to the key 101. At this time, the force applied from the solenoid 117 to the key 101 is a magnitude that causes the hammer 103 to generate a string-strength as represented by the string-striking information. Therefore, the hammer 103 has the same striking force as in the recording mode. A string force is generated, and the same movement as in the recording mode is reproduced by the continuous movement of the hammer 103.

Therefore, in such a conventional automatic playing piano, since the speed of movement of the hammer 103 is directly detected by the sensor 115 to form the information regarding the string striking force, the automatic playing function is provided from the beginning. Therefore, if the sensor 115 is arranged on the trajectory determined by the position and size of the hammer 103 in the piano manufacturing stage, the automatic playing piano can be constructed with a slight increase in the number of steps.

However, when it is desired to add an automatic performance function to a piano that has already been manufactured, the size of the key mechanism 107 of the piano, the size of the hammer 103, the mounting position, etc., differ for each manufacturer. Further, the same manufacturer may have different piano models, so that the orbit of the hammer 103 is not uniform. Therefore, when the sensor 115 for detecting the movement speed of the hammer 103 is to be attached to such an existing piano, the position of the sensor 115 and its attaching method are individually confirmed after confirming the attaching position of the hammer 103, its size, and the like. However, there was a problem that a large amount of cost and a large-scale construction were required for the automatic performance equipment of the existing piano.

On the other hand, instead of the hammer sensor, a keyboard sensor that detects the movement speed of the key may be used. The principle will be described below. First, in a keyboard instrument such as a piano, when a force is applied to the key 101 by pressing the key, the key 101 moves at a speed corresponding to the applied force, and the movement of the key 101 causes the movement of the key mechanism 107. The force applied to the key 101 is transmitted to the hammer 103.

Since the hammer 103 hits the strings in this way, its striking force can be estimated by detecting the movement speed of the key 101. Moreover, the mounting structure of the key 101 is almost constant regardless of the manufacturer of the piano and the model of the piano. In particular, the support structure from the reed 119 to the front 121 of the key 101 has a substantially constant structure in all the keys 101. Therefore, it is possible to design the sensor mounting position and mounting structure in advance.

Therefore, it is conceivable to dispose a keyboard sensor for detecting the movement of the key 101 as a sensor unit on the shelf plate 123 between the reed 119 and the front 121 of the reed. However, in this case, since the space between the reed inside 119 and the reed front 121 is narrow, the sensor unit itself must be thin and small.

Therefore, the conventional keyboard sensor is configured by attaching one encoder plate to the key 101 and forming one slit pattern on this plate. A light emitting element and a light receiving element of a photocoupler are arranged opposite to each other on both sides of the encoder plate (shutter). Therefore, in the conventional keyboard sensor 115 of this type, the passing speed of the shutter between two points is measured.

That is, since only one slit pattern is formed on one encoder plate, and eventually only one photo coupler is provided for one encoder plate, In order to improve the sensing accuracy and detect various movements of the key 101, for example, staccato, deep pianissimo, etc., it is necessary to arrange a plurality of pairs of encoder plates and photocouplers in the narrow space.

However, in such a conventional keyboard sensor, as described above, only one photocoupler is provided corresponding to one encoder plate, so that it must be arranged in a narrow space. As a key sensor that must be used, there was a problem that it was not suitable for enhancing the sensing accuracy for complicated movements of the key.

[0013]

[Problems to be solved by the device]

 As described above, the technique for detecting the speed of the hammer during performance recording varies greatly depending on the model, and there is a problem in that the mounting position and mounting method must be individually considered. On the other hand, when detecting the speed of the key, it was difficult to secure a sufficient space for mounting the keyboard sensor, and there was a problem that high sensing accuracy could not be obtained. On the other hand, according to a study made by the present inventors, the space between the key and the keyboard reed has a certain depth in the longitudinal direction of the key. Therefore, if this depth can be effectively used, it is thought that high sensing accuracy can be obtained even for keyboard sensors. The present invention has been made in view of the above-mentioned circumstances, and an object thereof is to provide a keyboard sensor that can obtain high sensing accuracy.

[0014]

[Means for Solving the Problems]

In order to solve the above problems, in this invention, a key provided so as to be swingable in the vertical direction, a light blocking member fixed to the key, and whether the light blocking member blocks the optical path or transmits the light. And a light sensor that outputs different detection signals according to the number of the light sensors, the number of the light sensors is N (N is an integer of 2 or more) arranged along the longitudinal direction of the key, and the light shielding member is provided. Has a light-transmitting portion, detects the position of the key with 2 ^N- step accuracy by the combination of the outputs of the N optical sensors, and determines the speed of the key or the rendition style applied to the key. It is characterized in that at least one of them is detected.

[0015]

[Action]

When the key swings in the vertical direction, the optical sensor outputs different detection signals depending on whether the light blocking member blocks the light path or transmits the light. Here, since N optical sensors (N is an integer of 2 or more) are arranged along the longitudinal direction of the key, the position of the key can be detected with an accuracy of 2 ^N steps by the combination of the outputs of these optical sensors. Then, at least one of the speed of the key and the rendition style applied to the key is detected.

[0016]

【Example】

 A. First Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 1 to 3 show a first embodiment of a keyboard sensor of an automatic piano playing apparatus according to the present invention. In FIG. 1, reference numeral 1 denotes a shelf board, and a key 7 is supported on a shelf 3 of the keyboard reed on the shelf board 1 via a balance key pin 5 so as to be vertically swingable. A key drive unit 13 is disposed in a flat space 11 defined below the key 7 and between the reed inside 3 and the reed front 9 and above the shelf 1.

As shown in detail in FIG. 2, the lock driving unit 13 has a U-shaped case 15 and a plurality of electromagnetic actuators 17 supported by the case 15. The electromagnetic actuator 17 moves (drives) the key 7 up and down via a swing lever 19. That is, the swing lever 19 is supported on the case 15 via the flange 21 so as to be vertically movable, and one end of the swing lever 19 is pushed up by the tip of the electromagnetic plunger of the electromagnetic actuator 17. The other end of the swing lever 19 is formed in a fork shape and engages with a horizontal piece 25 of a plate-like hook 23 protruding from the lower surface of the key 7 from above.

Further, a sensor unit 27 is arranged in front of the lock driving unit 13 in this space 11. The sensor unit 27 detects the vertical movement of the key 7 and outputs a detection signal to a control unit (CPU) (not shown). The sensor unit 27 is configured such that an encoder plate (shutter) 29, which is continuously formed at the lower end of the hook 23 that is fixed to the lower surface of the key 7 and protrudes downward, is provided with respect to the optical paths of the pair of photocouplers 31 and 33. It is provided so that it can appear and disappear freely. That is, on the encoder plate 29, as shown in FIG. 3, a pair of slit patterns (windows) 35 and 37 are vertically displaced from each other in a stepwise manner. Corresponding to the positions of the different slit patterns 35, 37, the pair of photocouplers 31, 33 composed of a light emitting element and a light receiving element are arranged on both side surfaces of the slit 41 of the case 39. That is, one slit pattern (window) 35 passes through the optical path of one photocoupler 31, and the other slit pattern (window) 37 passes through the optical path of the other photocoupler 33.

That is, in correspondence with each of the two photo couplers 31 and 33 (N = 2), the encoder plate 29 is provided with 2 along the vertical direction (the moving direction of the key 7). ² = 4 slit patterns 35 and 37 are formed. In the keyboard sensor having the above configuration, when the key 7 is lowered by the key depression operation, the shutter 29 is also lowered and the windows 35 and 37 cross the optical paths of the photocouplers 31 and 33, respectively. As a result, the photocouplers 31 and 33 output, for example, an OFF signal when the optical path thereof is blocked by the shutter 29, and an ON signal when light reaches the light receiving element through the windows 35 and 37. Further, in the non-key-depressed state (when the key is released), the shutter 29 is at the upper limit position and blocks the optical paths of the photocouplers 31 and 33. Then, in accordance with the movement of the key 7, the photocouplers 31 and 33 as a whole output four different types of signals as shown in Table 1 below based on the slit patterns (windows) 35 and 37.

[0020]

[Table 1]

In Table 1, the key 7 is highest at the fourth position and lowest at the first position. Then, based on the combination of these output signals, the controller calculates the position of the key 7 and the time (key pressing speed) required to move between the positions to determine the key 7 It detects the direction of movement, its speed, and its touch. For example, it is possible to detect and discriminate whether the key 7 has moved up or down, or whether or not the deep pianissimo, the shallow touch, the staccato, the repeated hits at the shallow position, the repeated hits at the deep position, or the like.

In the photocouplers 31 and 33, at least the light receiving side can be received at two places, and the shutter 29 is provided with a gap necessary for resolution. Practically, it is 0.5 mm or more. The gap of the shutter 29 is provided with a step according to the resolution for each row, but when there is no step, a step is provided between the one photo coupler 31 and the other photo coupler 33.

B. Second Embodiment FIGS. 4 and 5 show a second embodiment of the keyboard sensor of the automatic playing piano according to the present invention. As shown in these figures, in this embodiment, three windows (slits) 53, 55 of different sizes are arranged in the width direction of the encoder plate (shutter) 51 hung on the key. 57 are arranged side by side. These three windows 53, 55, 57 have different height positions, and the windows 53, 55, 57 have the same width, but the heights themselves are different in each row.

On the other hand, three photocouplers 61, 63 and 65 are fixed at predetermined positions corresponding to the windows 53, 55 and 57, respectively. That is, the windows 53, 55, and 57 are movably arranged in the optical paths of the photocouplers 61, 63, and 65, each of which is composed of a light receiving element and a light emitting element fixed to a predetermined portion. Further, four windows 53 are arranged at equal intervals in the height direction of the encoder plate 51 (direction in which the plate 51 moves). Two windows 55 and one window 57 are arranged and formed along the same direction. Therefore, these three rows of windows 53, 55, 57 allow eight different signals to be output to the encoder plate 51 along its height direction.

In other words, the keyboard sensor can detect eight positions in the height direction of the key. The height position of the key can be detected for the eight positions from the first to the eighth in correspondence with the vertical movement of the key by the encoder plate 51 having the above-mentioned configuration of the slit pattern. FIG. 5 shows a signal processing circuit that outputs a signal indicating the position of the key to the controller based on the output signal from each photocoupler.

That is, each output of each photocoupler 61, 63, 65 is input to the first to eighth AND circuits 71, 72, 73, 74, 75, 76, 77, 78 directly or via an inverter. The outputs of the AND circuits 71, 72, 73, 74, 75, 76, 77, 78 are respectively the first to eighth flip-flop circuits 81, 82, 83, 84, 85, 86, 87, 88. Each of the set terminals is manpowered. The reset terminals of the first to eighth flip-flop circuits 81, 82, 83, 84, 85, 86, 87, 88 are respectively provided with second to first AND circuits 72, 73, 74, respectively. Outputs of 75, 76, 77, 78, 71 are input.

That is, the reset terminal of the first flip-flop circuit 81 receives the output of the second AND circuit 72, and the reset terminal of the second flip-flop circuit 82 receives the output of the third AND circuit 73. The output of the fourth AND circuit 74 is output to the reset terminal of the third flip-flop circuit 83, the output of the fifth AND circuit 75 is output to the fourth flip-flop circuit 84, and the output of the fifth flip-flop circuit 85 is output to the fifth flip-flop circuit 85. The output of the AND circuit 76 of No. 6, the output of the seventh AND circuit 77 to the sixth flip-flop circuit 86, the output of the eighth AND circuit 78 to the seventh flip-flop circuit 87, , The output of the first AND circuit 71 is input to the eighth flip-flop circuit 88.

In the second embodiment having the above-mentioned configuration, the case where N = 3 in the present invention is shown, and three windows 53, 55, 57 are provided to three photocouplers 61, 63, 65 in a predetermined manner. By forming a pattern (2 ³ = 8 slit patterns) on one encoder plate 51, eight positions can be detected with respect to the vertical movement of the key. The sensing accuracy as a keyboard sensor can be improved. The output of the eight combinations allows the controller to detect a key touch etc. more accurately.

C. Reference Example Reference examples applying the present invention are shown in FIGS. This reference example is for two photocouplers (N = 2) as in the first embodiment. In this reference example, as shown in FIG. 6, two rows of windows 94 and 95 corresponding to two photo couplers 92 and 93 are attached to a single encoder plate 91 attached to a key in an upward and downward direction. A plurality of them are alternately formed at equal intervals.

As shown in FIG. 7, signals are input from the photocouplers 92 and 93 to the count-up pulse generator 96 and the count-down pulse generator 97, respectively. Has a signal input to the counter 98. The counter 98 converts into position information. FIG. 8 shows the output waveforms of the photocouplers 92 and 93 and the pulse generators 96 and 97, and the count value of the counter 98, respectively. In this reference example, since the number of slits (windows) of the encoder plate 91 is fixed, when the count value of the counter 98 exceeds the fixed range, the count value should be corrected to the boundary value. This makes it possible to correct an error caused by an error when the power is turned on and the reset circuit is unnecessary. The reset circuit is not necessary due to counter overflow or underflow.

[0031]

[Effect of device]

As described above, according to the keyboard sensor of the present invention, since N optical sensors are arranged along the longitudinal direction of the key and the position of the key is detected with the accuracy of 2 ^N steps, high sensing accuracy is obtained. It is possible.

[Brief description of drawings]

FIG. 1 is a side view of a first embodiment of a keyboard sensor of an automatic playing piano according to the present invention.

FIG. 2 is an exploded perspective view of a sensor unit according to a first embodiment of the present invention.

FIG. 3 is a front view of the encoder plate according to the first embodiment.

FIG. 4 is a front view of an encoder plate according to a second embodiment of the present invention.

FIG. 5 is a circuit diagram of an encoder circuit according to a second embodiment.

FIG. 6 is a front view of an encoder plate of a reference example.

FIG. 7 is a block diagram of a signal processing circuit of the above reference example.

FIG. 8 is a waveform diagram of the signal processing circuit of the reference example.

FIG. 9 is a side view showing a key driving unit of a conventional automatic playing piano.

[Explanation of symbols]

 7 key 29 encoder plate (light-shielding member) 31, 33 photocoupler (optical sensor) 35, 37 window (light-transmitting part)

Claims (1)

[Scope of utility model registration request] 1. A key provided so as to be vertically swingable,
In a keyboard sensor including a light-shielding member fixed to the key and an optical sensor that outputs a different detection signal depending on whether the light-shielding member shields the optical path or transmits the light, the optical sensor includes N along the length (N is 2
The above-mentioned integer) are provided, the light-shielding member has a light-transmitting portion, and the position of the key is detected with an accuracy of 2 ^N steps by the combination of outputs of the N optical sensors, and the speed of the key is determined. Alternatively, a keyboard sensor for detecting at least one of the rendition styles applied to the keys.