JPH03223899A - Key displacement detecting device for automatic piano - Google Patents

Abstract

PURPOSE:To detect a pressed key by a single detecting means by calculating the actual displacement quantities of respective keys according to the detection results of the distances to the reverse or top surfaces of respective keys and relative relation stored in a storage means. CONSTITUTION:The output voltage of a reflection type photosensor 1 is supplied to an A/D converter 2 and converted into digital data, which is supplied to a DSP(processor for digital signal processing) 3; and this DSP 3 has a RAM 4 for data storage internally and performs arithmetic processing according to a program. Consequently, key displacement quantity data corresponding to the actual displacement quantity S of a key 72 is calculated from data corresponding to the output voltage of the reflection type photosensor 1 supplied from the A/D converter 2 in order and outputted to a controller 5, which drives a solenoid 83. Consequently, the depressed key can be detected by the single detecting means.

Description

[Detailed Description of the Invention] This Industrial Application Field The present invention is directed to a player piano key Ql (i
t, regarding the detection device.

``Prior Art'' The operation of a player piano includes a recording mode in which the player's performance is recorded, and an automatic performance mode in which automatic performance is performed using recorded performance information or performance information supplied from the outside. In the recording mode, it is necessary to detect the player's key press and release operations and convert them into electrical signals. This type of player piano has conventionally been constructed as shown in FIG. In this figure, a player piano 71
The keyboard includes a plurality of keys 73, a string-striking mechanism 77 that transmits the movement of each key 73 to the hammer 75, and the hammer 75.
It has a string 79 that is struck by the string 79, and a damper 78 for suppressing the vibration of the string 79.

Each company 73 can swing freely around the balance pin 81, and I! When key 73 is pressed or a plunger protrudes from solenoid 83 and rotates key 73, this movement is transmitted to hammer 75 and damper 78 via string-striking mechanism 77.

As a result, the damper 78 separates from the string 79, and the hammer 75 rotates to the left in the drawing, thereby striking the string.

each#! A shutter 87 is attached to the back surface of each of the shutters 73, and a transmission type photo ink converter 89 is disposed below each of the shutters 73 so that the transmitted light is blocked by the shutter 87.

The output signal of the transmission type photointerrupter 89 is supplied to the controller 85, and the controller 85 determines whether each key a73 is pressed or released.

``Problem to be Solved by the Invention'' By the way, in the recording mode for recording a performance based on a performance idea, information on whether or not 1s73 is pressed (key on/off signal) alone is insufficient as performance information. Information (velocity of the MIDI signal) regarding the string striking strength determined in accordance with the key striking strength, that is, the strength with which the hammer 75 strikes the string 79 is also required. However, in the above-mentioned conventional player piano 71, since the vertical movement of the nyatta 87 attached to each company 73 is detected by the photo ink club 89, it is difficult to detect whether the -key 73 is pressed or released. Although it is possible, it has not been possible to continuously detect the displacement of the key 73 and obtain the key-strike strength that is related to the string-strike strength. For example, each company could have multiple photointerrupters to discretely detect the displacement of the key to obtain keystroke strength, but the installation of each detection device may be due to accuracy errors or non-continuous detection. However, the detection accuracy of the keystroke strength decreases. In addition, the shutter 87 and the photo ink bumper 89 must be installed for each key 73, and detection errors may occur due to the accuracy of these installations and changes in their positions over time. , there is also the problem of low detection accuracy and reliability, and furthermore, the shutter 8
7 must be attached to the lower surface of the back side of each t173, there is also the problem that mounting work during manufacturing and maintenance and inspection work are complicated.

This invention has been made in view of the above-mentioned circumstances, and is a key to a player piano that is capable of not only detecting pressed and released keys but also continuous and highly accurate detection of key displacement using a single detection means. The object of the present invention is to provide a displacement detection device.

"Means for Solving the Problem" In order to solve the above-mentioned problem, in this invention,
A detection means that non-contact detects the distance to the back or front surface of each manufacturer of player pianos, and a relative relationship between the distance to the back or front surface of each H detected by the detection means and the actual displacement amount of each manufacturer. It is characterized by comprising a storage means for storing each of them, and a calculation means for calculating the displacement amount of each company based on the detection result of the nη detection means and the relative relationship stored in the storage means. It is said that

"Operation" According to the above configuration, the distance to the back side or the front side of each company is detected by the detection means, and the installation of the detection means is determined based on the detection result and the relative relationship stored in the storage means. Regardless of accuracy, each company's actual displacement amount is calculated individually.

"Embodiments" Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing the configuration of an embodiment of the present invention. In this figure, l is a reflective photosensor arranged below each company 73, and as shown in FIG.
A light emitting element 1a that irradiates light onto the back surface of the light emitting element 1a and a light receiving element 1b that receives reflected light from the light emitting element 1a are integrally provided within a case.

The relationship between the relative output voltage (%) of the output voltage Vout of the reflective photosensor 1 and the distance d(a+m) to the back surface of the key 73, which is the detection object, is as shown in FIG. Among these, when focusing on the range of distance d'p3+ml11 to 9I in particular, the relationship shown in FIG. 4 is obtained. This figure shows the output voltage Vout obtained within the range of distance d4-3111m to 9nv in a log-logarithmic graph.
If t is Y, Y = 5.2 X −'−” −=・
It can be expressed by the approximate expression −(+).

Here, the relationship between relative output voltage and distance shown in Figure 3 is:
(This is due to individual differences in the characteristics of reflective photosensors) r4
-ru. For example, if the output voltage of the reflective photosensor is negative even at the same distance, the straight line in FIG. 4 will be shifted by . Therefore, individual differences in the characteristics of reflective photosessors are absorbed by considering equivalently the case where the distance is in the range of about 3 mm to 9 mm and the case where the distance is the sum of 5. Assuming that the memory (1) is valid in a wider range than 3 mm to 9 mm, the distance 1111bl is determined from the output voltage using the above equation (1). This is possible because only the relative value of the distance is used in the proportional allocation calculation described later.

Therefore, the distance (1) to the back surface of the key 73 is based on the output voltage VouL of the reflective photosensor 1,
You can see what is required from the formula. And distance d43mm
The reflective photosensor I is arranged as shown in FIG. 5 so as to satisfy the range of 9 mm. Of course, the position of the back of 1!73 when the key is released (the position indicated by the solid line in Figure 1) is the same as the position of the back of 1!73 when the key is pressed in (by pressing the 17th key) ( The distance d+ax from the reflective photosensor 1 to the position IL and the distance dIIlin from the reflective photosensor 1 to the position IL are within the range of 9111m to 31III11. , the mounting position (height) of the reflective photosensor l is set.

The output voltage Vout of the reflective photosensor l having such characteristics is supplied to the A/D converter 2 shown in FIG. Supplied. This DSP
3 has a built-in RAM 4 for data storage, and executes arithmetic processing to be described later based on a program stored in a program memory (not shown), thereby sequentially supplying data from the A/D converter 2. Key displacement amount data corresponding to the actual displacement amount S (-〇~IO+++n+) of the key 73 is sequentially calculated from the data corresponding to the output voltage Vout of the reflective photosensor l, and this key displacement amount data is sent to the controller 5.
Output to. The controller 5 is a CPU.

The microcomputer includes a ROM, RAM, bank-up RAM, Ilo, etc., and a solenoid driver for driving the solenoid 83.

Next, in a double series of examples, the sixth section regarding the operation of I) S
This will be explained with reference to the figures.

First, in step SPI, perform the initial settings.
It's true. 4 “Nawashi, bank up 1 in controller 5
(,・Maximum f/i (I m a d
Store min (≧3 mm) in RAM 4. These maximum value dmax and minimum value dmn depend on the installation position (height) of the reflective photosensor l; 73
f5, and also varies slightly depending on the degree of expansion and contraction of the wood itself that makes up the six keys 73 and the aging of each part. Therefore, these maximum value dmax and minimum value dmin are determined from the controller 5 at the time of product shipment, periodic inspection, performance start, or test mode performed as necessary.・Drive 83 and set 3 keys 73 to Class 5: -Full stroke a-7 (10mm) f? Moved Uo,
04wl', 37') processing (step SP
From the distance d obtained in steps 2 and 5P3), the maximum value dmax and minimum value d+in are determined for each key 73, and stored in a backup RAM or the like in the controller 5.

Then, by the initial setting of step SPI, the maximum value dmax for each key 73 supplied from the controller 5 is
and the minimum value dmin are respectively stored in the RAM 4 in each DSP 3, each DSP 3 performs the following steps SP2 to SP.
Repeat step 5.

First, in step SP2, digital data corresponding to the output voltage VouL of the reflective photosensor 1 supplied from the A/D converter 2 is captured, and the digital data is inputted to the next step S.
In P3, the above-mentioned approximate formula Y=5.2X-'・4
1, the distance d to the detection surface is calculated.

Next, in step SP4, based on the maximum value dmax and minimum value dn+in stored in the RAM 4, the distance Md is converted into the actual displacement amount (also called struggle amount) of the key 73 by proportional allocation calculation. .

In other words, since the stroke of 1!73 is IOmn+, if the distance d is the maximum value dmax, the N displacement amount O
mm, and the distance (if I is the minimum value dn + in, it corresponds to a key displacement of 1110 mm. Therefore, the maximum value dm
By proportionally distributing the key displacement values 0 to 1001111 according to the ratio of the distance (I) between ax and the minimum value dmin, the key displacement 1η amount corresponding to the distance Md is calculated. Step 5P5) to output the actual key displacement M to the controller 5, and then step SP
Returning to step 2, the same arithmetic processing operation is repeated.

According to such an embodiment, the maximum value dmax and the minimum value d+ of the distance d to the key 73 determined in advance for @key 73ftj
+in, the current distance d was converted to the actual displacement of N73 by 4 degrees by proportional distribution calculation, so the installation of the reflective photosensor I was done regardless of the accuracy of the position (height). First, the actual displacement amount of the key 73 can be obtained with high precision. Here, as described above, the individual differences in the characteristics of the reflective photosensor l can be equivalently replaced with the unit of distance, so the proportional allocation calculation does not suffer from the adverse effects of the individual differences. In addition, since the reflective photosensor 1 directly detects the wooden surface of the back of the key 73 as the detection surface, i! There is no need to perform equivalent processing or attach a reflective plate to the 73 side, making mounting and maintenance inspection easy.Furthermore, the reflective photosensor itself has a
Since it is an extremely small component of approximately 2.7 tam, it occupies a small area and can be incorporated into various types of player pianos.

In the embodiment described above, for each key 73, A
The explanation has been given using an example where the A/D converter 2 and the DSP 3 are each provided, but for example, for 16 keys 73, one set of A/D converters 2 and
A D converter 2 and a D S P 3 are provided, and the output signal V o of the reflective photosensor l provided for the six keys 73 is
Of course, it is also possible to configure ut to be sequentially selected by an analog multiplexer and processed sequentially by a set of A/D converters I52 and DSP3.

In addition, a reflective photosensor l is attached to the balance bin 8 shown in FIG. It is of course possible to arrange it above R73 on the left side of the key 73 and detect the distance to the top surface of the key 73.

"Effects of the Invention" As explained above, according to the present invention, there is provided a detection means for detecting the distance to the back or front surface of each of the six keys of a player piano without contact, and the distance between the six keys detected by the detection means. Based on a storage means that stores the relative relationship between the distance to the back surface or the front surface and the actual displacement amount of the three keys, and the detection result of the detection means and the relative relationship stored in the storage means, Since it is equipped with a calculation means to calculate the displacement amount of the 6th key of the 11th note, the installation of the detection means is easy regardless of the accuracy.
The actual displacement amount of each of the six keys is calculated, and as a result, the single detection means can not only simply detect the pressed HN but also continuously and highly accurately detect the displacement of the key. In addition, the company's regulations have the advantage that there is no need to perform equivalent processing or to attach detected parts, and there is no harm to the key tab, making mounting and maintenance inspection easier.

・11 simple drawings +15. Explanation: FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.
Figure 2 is a circuit diagram showing the configuration of the reflective photosensor l of the same example, Figure 3 is a diagram showing the output characteristics of the reflective photosensor l, and Figure 4 is the output characteristic of the reflective photosensor l. FIG. 5 is a diagram for explaining the mounting position of the reflective photosensor i, and FIG. 6 is a flowchart for explaining the operation of an embodiment of the present invention. FIG. 7 is a block diagram showing the configuration of a conventional player piano.

l...Reflection type photosensor (detection means), 2.
...A/D converter, 3...DSP (calculating means), 4...RAM (storage means), 73...key.

Claims (1)

[Scope of Claims] Detection means for detecting the distance to the back side or front side of each key of a player piano in a non-contact manner, and the distance to the back side or front side of each key detected by the detection means and each actual key. storage means for storing the relative relationship with the displacement amount of each key; and calculation means for calculating the displacement amount of each key based on the detection result of the detection means and the relative relationship stored in the storage means. A key displacement detection device for a player piano, comprising: