ELECTRONIC PERCUSSION INSTRUMENT AND SOUND PRODUCTION CONTROL METHOD THEREOF

TECHNICAL FIELD

The present invention relates to an electronic percussion instrument. Particularly, the present invention relates to an electronic percussion instrument that can realize an operation similar to choke playing in an acoustic percussion instrument.

DESCRIPTION OF RELATED ART

An electronic cymbal is one type of electronic percussion instrument. In an electronic cymbal in Patent Literature 1, a band-like pressure sensor (edge sensor) is disposed at a peripheral part (edge part) of a cymbal pad constituting a struck surface. When the edge part of the cymbal pad is gripped by a user and the edge sensor is turned on, choke control (mute control) of a musical sound that is being produced is performed. Patent Documents

[Patent Literature 1]

Japanese Patent Laid-Open Publication No. 2002-207481

[Patent Literature 2]

Japanese Patent Laid-Open Publication No. H09-311679

However, in an electronic cymbal, even if a user grips a cymbal pad, when a grip position is inside the inner circumference of the cymbal pad and the edge sensor is not disposed in this part, the edge sensor does not turn on. Therefore, it is not possible to perform choke control.

In addition, even if the edge part at which the edge sensor is disposed is gripped, the edge sensor may not turn on unless it is gripped strongly to some extent. Therefore, a user is forced to perform an operation different from choke playing with an acoustic cymbal or the like. In addition, it is not possible to realize playing such as touching the struck surface and muting as with an acoustic cymbal or the like.

In addition, in the electronic percussion instrument device in Patent Literature 2, a touch on a conductive striking component being detected and a signal of a musical sound that is produced being mute-controlled is described. However, in this electronic percussion instrument device, even if it can be detected whether a touch has occurred, it is difficult to detect a state (degree) of touching.

SUMMARY

The present invention has been made in order to solve the above problems, and an object of the present invention is to provide an electronic percussion instrument that can realize an operation similar to choke playing in an acoustic percussion instrument.

Solution to Problem

In order to achieve the above object, an electronic percussion instrument of the present invention includes a struck surface, a striking sensor configured to detect striking on the struck surface, and a sound production control unit configured to perform sound production control on a musical sound according to a detection result of the striking sensor. The electronic percussion instrument includes an electrostatic capacitance sensor having an electrode disposed on a side opposite to the struck surface, and an attenuation control unit configured to perform attenuation control to the musical sound that is being produced by the sound production control unit according to an output value of the electrostatic capacitance sensor.

According one of the embodiments of the disclosure, a sound production control method is provided. The method detects a strike on a struck surface of an electronic percussion instrument and performs sound production control on a musical sound according to detecting result of the strike. The method includes constructing at least one electrostatic capacitance sensor by forming an electrode on a side opposite to the struck surface, and an output value of the electrostatic capacitance sensor changes in accordance with a contact state of a touch by a user when the user touches the struck surface, and performing an attenuation control to the musical sound that is being produced according to the output value of the electrostatic capacitance sensor.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an electronic cymbal according to an embodiment of the present invention.

FIG. 2(a) is a diagram schematically showing an electrical configuration of an electrostatic capacitance sensor, and FIG. 2(b) is a block diagram showing an electrical configuration of an electronic cymbal.

FIG. 3(a) is a flowchart of a periodic process. FIG. 3(b) is a flowchart of a striking detection process.

FIG. 4 is a flowchart of an electrostatic capacitance sensor process.

FIG. 5(a) is a flowchart of an edge sensor process. FIG. 5(b) is a flowchart of a choke process.

FIG. 6 is a diagram showing an electrostatic capacitance sensor according to a second embodiment.

FIG. 7 is a block diagram showing an electrical configuration of an electronic cymbal according to the second embodiment.

FIG. 8 is a flowchart of a periodic process according to the second embodiment.

FIG. 9(a) is a flowchart of a second electrostatic capacitance sensor process according to the second embodiment and FIG. 9(b) is a flowchart of a second choke process according to the second embodiment.

FIG. 10 is a diagram showing a shape of an electrode of an electrostatic capacitance sensor according to a modified example.

FIGS. 11(a)˜11(j) are diagrams showing shapes of electrodes of an electrostatic capacitance sensor in a modified example.

FIGS. 12(a)˜12(c) are diagrams showing shapes of electrodes of an electrostatic capacitance sensor in a modified example.

FIG. 13(a) is a front view of an electronic drum pad in a modified example.

FIG. 13(b) is a cross-sectional view of the electronic drum pad in the XIIIb part in FIG. 13(a).

FIG. 13(c) is a schematic view of the electronic drum pad in the XIIIc part in FIG. 13(b).

DESCRIPTION OF THE EMBODIMENTS

Preferable embodiments of the present invention will be described below with reference to the appended drawings. A first embodiment of the present invention will be described with reference to FIG. 1 to FIGS. 5(a) and 5(b). First, a schematic configuration of an electronic cymbal 1 as an electronic percussion instrument of the present invention will be described with reference to FIG. 1. FIG. 1 is a perspective view of the electronic cymbal 1 according to an embodiment of the present invention.

The electronic cymbal 1 includes a struck surface 2, a striking sensor 3, an edge sensor 4, and an electrostatic capacitance sensor 5. The struck surface 2 is formed of a disk-shaped rubber member which is struck by a user with a stick, and is formed to cover a disk-shaped plate (not shown) disposed on the side opposite to the struck surface 2.

The striking sensor 3 is a piezoelectric sensor configured to detect striking on the struck surface 2, and is disposed at two places on the disk-shaped plate disposed on the side opposite to the struck surface 2. When the struck surface 2 is hit by a user, the striking sensor 3 detects its vibration and transmits the strength of the vibration to a CPU 10 (refer to FIG. 2(b)) of the electronic cymbal 1. The CPU 10 calculates a velocity according to the strength of the vibration and generates a musical sound based on the calculated velocity.

The edge sensor 4 is a pressure sensor configured to detect that the outer circumferential part of the struck surface 2 is being gripped by the user, and is disposed along the outer circumference of the disk-shaped plate disposed on the side opposite to the struck surface 2. The edge sensor 4 transmits “1” in an “ON” state and “0” in an “OFF” state to the CPU 10. The CPU 10 performs attenuation control of a musical sound that is being produced in a condition in which the edge sensor 4 is in an “ON” state. Therefore, when the edge sensor 4 detects that the outer circumferential part of the struck surface 2 is being gripped by the user, it is possible to simulate choke playing in which a musical sound during playing is attenuated.

The electrostatic capacitance sensor 5 is a sensor configured to detect that a human body such as a user's hand is touching the struck surface 2, and an electrode 5a is disposed between the struck surface 2 and the disk-shaped plate disposed on the side opposite to the struck surface 2. The electrostatic capacitance sensor 5 transmits an increase or decrease (change) in a virtual electrostatic capacitance due to touch of a human body to the CPU 10. When approach of a human body is detected by the CPU 10 according to an output value of the electrostatic capacitance sensor 5, attenuation control of a musical sound that is being produced is performed. Therefore, according to the electrostatic capacitance sensor 5, when the user touches the struck surface 2, it is possible to simulate choke playing in which a musical sound during playing is attenuated. In order to reduce any influence on the electrostatic capacitance sensor 5, the struck surface 2 and the disk-shaped plate disposed on the side opposite to the struck surface 2 are formed of an insulator or a conductor that is not connected to a reference potential point or the electrostatic capacitance sensor 5.

The electrostatic capacitance sensor 5 will be described with reference to FIG. 2(a). FIG. 2(a) is a diagram schematically showing an electrical configuration of the electrostatic capacitance sensor 5. A shown in FIG. 2(a), in the electrostatic capacitance sensor 5, the electrode 5a is connected to a control unit 5b via a resistor 5c. The electrode 5a is formed in two lines, a thick (large area) electrode 5a1 is disposed on the outer circumferential side and a thin (small area) electrode 5a2 is disposed on the inner circumferential side. The two lines of the electrodes 5a1 and 5a2 are connected to each other to form one electrode 5a.

The electrode 5a has a PET material laminated thereon. Therefore, even if striking by the user is transmitted to the electrode 5a through the struck surface 2, it is possible to prevent damage to the electrode 5a. In addition, the electrode 5a that is “freely movable” is adhered to the disk-shaped plate on the side opposite to the struck surface 2. That is, the entire surface of the electrode 5a is not adhered to the plate, but the electrode 5a is partially adhered to the plate. Therefore, even if the electrode 5a or the plate on the side opposite to the struck surface 2 expands or contracts due to change in temperature, it is possible to prevent damage such as breakage of the electrode 5a due to “free mobility.”

The control unit 5b is a control circuit in which various switches, a CPU, and the like are mounted. The resistor 5c is an element for electrostatic protection. A sampling capacitor 5d is a capacitor used for repeatedly sending an electric charge charged into a parasitic capacitance capacitor 5e to be described below and measuring the number of repetitions until a voltage of the sampling capacitor 5d becomes a predetermined value or higher.

The parasitic capacitance capacitor 5e is a virtual capacitor formed between the electrode 5a and a conductor to be detected such as a human body. Since the human body has a large electrostatic capacitance, the electrostatic capacitance of the parasitic capacitance capacitor 5e increases as the human body approaches the electrode 5a. Therefore, an amount of electric charge charged into the parasitic capacitance capacitor 5e increases as the human body approaches the electrode 5a.

The electrostatic capacitance sensor 5 repeats a process of transmitting an electric charge to the electrode 5a according to a switching operation in the control unit 5b, charging the parasitic capacitance capacitor 5e, and sending the charged electric charge to the sampling capacitor 5d. The electrostatic capacitance sensor 5 detects change in the electrostatic capacitance of the parasitic capacitance capacitor 5e based on the number of repetitions until the voltage of the sampling capacitor 5d becomes a predetermined value or higher and determines whether a human body has approached the electrode 5a.

Here, as the electrostatic capacitance of the parasitic capacitance capacitor 5e becomes larger (as a distance between the electrode 5a and the human body becomes shorter), since an amount of electric charge sent from the parasitic capacitance capacitor 5e to the sampling capacitor 5d in one cycle becomes larger, the number of repetitions decreases. Since an output value of the electrostatic capacitance sensor 5 corresponding to the number of repetitions is output, it is possible to determine that a human body has approached the electrode 5a when the output value of the electrostatic capacitance sensor 5 is smaller. In the present embodiment, the electrostatic capacitance sensor 5 outputs a value of 650 to 850 according to the number of repetitions. In addition, a resistance value of the resistor 5c and an electrostatic capacitance of the sampling capacitor 5d may be appropriately set according to a desired performance. While the electrostatic capacitance sensor 5 of a general self-capacitance type has been described above, other types of electrostatic capacitance sensors may be used.

Next, an electrical configuration of the electronic cymbal 1 will be described with reference to FIG. 2(b). FIG. 2(b) is a block diagram showing an electrical configuration of the electronic cymbal 1. The electronic cymbal 1 includes the CPU 10, a ROM 11, a RAM 12, the striking sensor 3, the edge sensor 4, the electrostatic capacitance sensor 5, and a sound source 13, and these are connected to one another via a bus line 16. An amplifier 14 is connected to the sound source 13 and a speaker 15 is connected to the amplifier 14.

The CPU 10 is a computation device configured to control respective units connected via the bus line 16. The ROM 11 is a non-rewritable memory. In the ROM 11, a control program 11a executed by the CPU 10 and fixed value data (not shown) referred to by the CPU 10 when the control program 11a is executed are stored. When the control program 11a is executed by the CPU 10, a periodic process and a striking detection process in FIGS. 3(a) and 3(b) are performed.

The RAM 12 is a memory in which various types of work data, and flags and the like used when the CPU 10 executes a program such as the control program 11a are stored in a rewritable manner. In the RAM 12, a velocity memory 12a, a velocity threshold value change flag 12b, a velocity threshold value changing counter 12c, a striking position memory 12d, an edge sensor output value memory 12e, an edge sensor value memory 12f, an edge sensor detection waiting counter 12g, an electrostatic capacitance sensor output value memory 12h, an electrostatic capacitance sensor value memory 12i, and a choke setting value memory 12j are provided.

The velocity memory 12a is a memory in which a velocity of a musical sound calculated from the output value of the striking sensor 3 is stored. When power is supplied to the electronic cymbal 1, the state is initialized to “0” indicating that no velocity is stored. In the striking detection process in FIG. 3(b), a velocity is calculated based on the output value from the striking sensor 3, and is stored in the velocity memory 12a (FIG. 3(b), S5). Then, a musical sound corresponding to the velocity memory 12a is generated (FIG. 3(b), S8). The velocity memory 12a has a value in a range of 0 (weak) to 127 (strong) according to the strength of striking detected by the striking sensor 3.

The velocity threshold value change flag 12b is a flag for determining whether or not to change a threshold value of striking detection by the striking sensor 3 in a condition in which a human body has approached the struck surface 2. When power is supplied to the electronic cymbal 1 or when the periodic process in FIG. 3(a) is initialized (FIG. 3(a), S1), the state is initialized to “OFF” indicating that a threshold value of striking detection has not changed. In an electrostatic capacitance sensor process in FIG. 4, when the output value (that is, the value of the electrostatic capacitance sensor output value memory 12h to be described below) of the electrostatic capacitance sensor 5 is smaller than a velocity change threshold value to be described below and the value of the velocity threshold value changing counter 12c to be described below is shorter than a threshold value change time to be described below, the velocity threshold value change flag 12b is set to ON.

When choke playing due to touching the struck surface 2 is performed for a short time (when choke playing is quickly performed), touching the struck surface 2 with a user's hand may be erroneously detected as striking. Thus, in order to prevent such erroneous detection, in the electrostatic capacitance sensor process in FIG. 4, when the value of the electrostatic capacitance sensor output value memory 12h is smaller than the velocity change threshold value, the velocity threshold value change flag 12b is turned ON for the threshold value change time. In the striking detection process in FIG. 3(b), when the velocity threshold value change flag 12b is turned ON and the value of the velocity memory 12a is larger than a striking threshold value to be described below, a musical sound is produced and when the value of the velocity memory 12a is equal to or smaller than the striking threshold value, no musical sound is produced. In addition, when the velocity threshold value change flag 12b is OFF, even if the value of the velocity memory 12a is equal to or smaller than the striking threshold value, a musical sound is produced. That is, when the velocity threshold value change flag 12b is ON, the threshold value of the value of the velocity memory 12a for producing a musical sound becomes larger. Therefore, it is possible to prevent erroneous production of a musical sound due to impact on the struck surface 2 according to choke playing.

The velocity threshold value changing counter 12c is a counter that measures a duration time for which the velocity threshold value change flag 12b is ON. When power is supplied to the electronic cymbal 1 or in the electrostatic capacitance sensor process in FIG. 4, if the value of the electrostatic capacitance sensor output value memory 12h is equal to or larger than the velocity change threshold value, “0” is set (FIG. 4, S25). When the value of the electrostatic capacitance sensor output value memory 12h is smaller than the velocity change threshold value, 1 is added to the velocity threshold value changing counter 12c (FIG. 4, S23). That is, when the velocity threshold value change flag 12b is switched from OFF to ON, 1 is periodically added to the value of the velocity threshold value changing counter 12c. The velocity threshold value change flag 12b is turned OFF when the value of the velocity threshold value changing counter 12c is equal to or larger than the threshold value change time to be described below. A threshold value of the value of the velocity memory 12a for producing a musical sound is changed by the velocity threshold value changing counter 12c for a certain time (that is, for the threshold value change time). Therefore, when a hand holding a stick is brought into contact with the struck surface 2 and performs playing, if the threshold value change time has passed, since the threshold value of the value of the velocity memory 12a for producing a musical sound is returned to its original value, it is possible to reduce a feeling of discomfort in playing to a minimum.

The striking position memory 12d is a memory in which a striking position for the musical sound calculated from the output value of the striking sensor 3 is stored. When power is supplied to the electronic cymbal 1, the state is initialized to “0” indicating that no striking position is stored. In the striking detection process in FIG. 3(b), a striking position is calculated based on the output value from the striking sensor 3, and is stored in the striking position memory 12d (FIG. 3(b), S5). In the present embodiment, the striking position is a distance from the center of the struck surface 2. Then, a musical sound corresponding to the striking position memory 12d is generated (FIG. 3(b), S8).

The edge sensor output value memory 12e is a memory in which a sensor output value from the edge sensor 4 is stored. When power is supplied to the electronic cymbal 1 or immediately after the periodic process in FIG. 3(a) starts, the state is initialized to “0” indicating that the edge sensor 4 is not detected. Then, in an edge sensor process in FIG. 5(a), the output value of the edge sensor 4 is stored (FIG. 5(a), S30). In the present embodiment, when the edge sensor 4 is detected, “1” is output from the edge sensor 4, and when the edge sensor 4 is not detected, “0” is output. That is, when the value of the edge sensor output value memory 12e is “0,” this indicates that the edge sensor 4 is not detected, and when the value of the edge sensor output value memory 12e is “1,” this indicates that the edge sensor 4 is detected.

The edge sensor value memory 12f is a memory in which an ON/OFF state of the edge sensor 4 is stored. When power is supplied to the electronic cymbal 1, the state is initialized to “0” indicating that the edge sensor 4 is OFF. When the edge sensor output value memory 12e is “1” and the edge sensor detection waiting counter 12g to be described below is equal to or longer than a detection waiting time, “1” is set in the edge sensor value memory 12f.

The ON/OFF state of the edge sensor 4 is determined by the edge sensor value memory 12f in order to prevent unintended choke playing due to chattering of the edge sensor 4 or the like. In the electronic cymbal 1, a user grasps (grips) the edge sensor 4 with his or her finger and thereby performs choke playing. When the user tries to grip the edge sensor 4 during playing, he or she may accidentally touch the edge sensor 4 during playing. In such a case, when the sensor output value of the edge sensor 4 is directly used as choke playing information, unintended choke playing may be performed. In order to prevent this playing, the edge sensor value memory 12f becomes “1” only when the edge sensor output value memory 12e is “1” and the edge sensor detection waiting counter 12g to be described below is a detection waiting time or longer. Therefore, after the output value of the edge sensor 4 is stabilized, the ON/OFF state of the edge sensor 4 used in choke playing is determined, and thus unintended choke playing can be prevented. According to results obtained by calculating values of the edge sensor value memory 12f and the electrostatic capacitance sensor value memory 12i to be described below, attenuation control of a musical sound that is being produced (that is, a choke process) is performed.

The edge sensor detection waiting counter 12g is a counter that measures a duration time for which the sensor output value of the edge sensor 4 is “1.” When power is supplied to the electronic cymbal 1 or in the edge sensor process in FIG. 5(a), if the value of the edge sensor output value memory 12e is “0,” “0” is set (FIG. 5(a), S35). When the value of the edge sensor output value memory 12e is “1” and the value of the edge sensor detection waiting counter 12g is shorter than the detection waiting time to be described below, 1 is added to the edge sensor detection waiting counter 12g (FIG. 5(a), S33). That is, a time from when the value of the edge sensor output value memory 12e becomes “1” until the detection waiting time elapses is measured by the edge sensor detection waiting counter 12g.

The electrostatic capacitance sensor output value memory 12h is a memory in which the sensor output value from the electrostatic capacitance sensor 5 is stored. When power is supplied to the electronic cymbal 1 or immediately after the periodic process in FIG. 3(a) starts, the state is initialized to “0” indicating that the electrostatic capacitance sensor 5 is not detected. Then, when the electrostatic capacitance sensor process in FIG. 4 is initialized, the output value of the electrostatic capacitance sensor 5 is stored (FIG. 4, S20).

The electrostatic capacitance sensor value memory 12i is a memory in which the sensor value of the electrostatic capacitance sensor 5 calculated based on the electrostatic capacitance sensor output value memory 12h is stored. When power is supplied to the electronic cymbal 1 or in the electrostatic capacitance sensor process in FIG. 4, if the value of the electrostatic capacitance sensor output value memory 12h is equal to or larger than an electrostatic capacitance sensor detection threshold value to be described below, “0” indicating that the electrostatic capacitance sensor 5 is not detected is set. In the electrostatic capacitance sensor process in FIG. 4, when the value of the electrostatic capacitance sensor output value memory 12h is smaller than the electrostatic capacitance sensor detection threshold value, a value obtained by subtracting the value of the electrostatic capacitance sensor output value memory 12h from the electrostatic capacitance sensor detection threshold value is stored in the electrostatic capacitance sensor value memory 12i (FIG. 4, S27). That is, a difference between the electrostatic capacitance sensor output value memory 12h and the electrostatic capacitance sensor detection threshold value is stored in the electrostatic capacitance sensor value memory 12i. According to the result obtained by computing the value of the electrostatic capacitance sensor value memory 12i and the value of the edge sensor value memory 12f, attenuation control of a musical sound that is being produced (that is, the choke process) is performed.

The choke setting value memory 12j is a memory in which an attenuation setting value in the choke process for a musical sound that is being produced is stored. When power is supplied to the electronic cymbal 1 or immediately after the choke process in FIG. 5(b) starts, “0” indicating that no attenuation control is performed is set. Then, in the choke process in FIG. 5(b), an attenuation setting value obtained by weighting the value of the edge sensor detection waiting counter 12g and the value of the electrostatic capacitance sensor value memory 12i is stored in the choke setting value memory 12j (FIG. 5(b), S40). The electronic cymbal 1 performs attenuation control according to the value of the choke setting value memory 12j on an arbitrary musical sound that is being produced and thus simulates choke playing.

The sound source 13 is a device that controls tones and various effects of a musical sound generated according to an instruction from the CPU 10. The amplifier 14 is a device that amplifies a musical sound signal generated in the sound source 13 and outputs the amplified musical sound signal to the speaker 15. The speaker 15 emits (outputs) the musical sound signal amplified by the amplifier 14 as a musical sound.

Next, a control program executed by the CPU 10 of the electronic cymbal 1 will be described with reference to FIGS. 3(a) and 3(b) to FIGS. 5(a) and 5(b). FIG. 3(a) is a flowchart of the periodic process. States of the edge sensor 4 and the electrostatic capacitance sensor 5 are acquired, and the choke process is performed on an arbitrary musical sound that is being produced according to the states of the sensors. According to a detection state of the electrostatic capacitance sensor 5, and according to choke playing or the like, it is determined whether the user is in contact with the struck surface 2. The periodic process is repeatedly performed every 100 μsec according to an interval interrupting process every 100 μsec.

First, the velocity threshold value change flag 12b is set to OFF (S1). In the electrostatic capacitance sensor process to be described below (S2), since the velocity threshold value change flag 12b is set to ON according to the output value of the electrostatic capacitance sensor 5, the velocity threshold value change flag 12b is set to OFF when the periodic process repeatedly performed is initialized. After the process of S1, the electrostatic capacitance sensor process is performed (S2). The electrostatic capacitance sensor process will be described with reference to FIG. 4.

FIG. 4 is a flowchart of the electrostatic capacitance sensor process. In the electrostatic capacitance sensor process, an output value of the electrostatic capacitance sensor 5 is acquired, and it is determined whether or not to change a threshold value of striking detection by the striking sensor 3 according to the output value of the electrostatic capacitance sensor 5. In addition, a sensor value of the electrostatic capacitance sensor 5 used in the choke process in FIG. 5(b) is calculated from the output value of the electrostatic capacitance sensor 5, and is stored in the electrostatic capacitance sensor value memory 12i.

First, in the electrostatic capacitance sensor process, the output value of the electrostatic capacitance sensor 5 is stored in the electrostatic capacitance sensor output value memory 12h (S20). After the process of S20, it is checked whether the value of the electrostatic capacitance sensor output value memory 12h is smaller than the velocity change threshold value (for example, 820) (S21). The velocity change threshold value is set according to an output value from the electrostatic capacitance sensor 5 when a human body lightly touches the struck surface 2. The velocity change threshold value may be set to 820 or more or 820 or less according to a detection ability (sensitivity) of the electrostatic capacitance sensor 5 and a material of the struck surface 2.

When the value of the electrostatic capacitance sensor output value memory 12h is smaller than the velocity change threshold value (Yes in S21), it is checked whether the velocity threshold value changing counter 12c is smaller than the threshold value change time (for example, 5,000, that is, 0.5 seconds) (S22). When the velocity threshold value changing counter 12c is shorter than the threshold value change time (Yes in S22), 1 is added to the velocity threshold value changing counter 12c (S23), and the velocity threshold value change flag 12b is set to ON (S24). On the other hand, when the velocity threshold value changing counter 12c is equal to or larger than the threshold value change time (No in S22), the processes of S22 to S24 are skipped.

When the value of the electrostatic capacitance sensor output value memory 12h is smaller than the velocity change threshold value, the velocity threshold value change flag 12b is set to ON during the threshold value change time. On the other hand, when the velocity threshold value changing counter 12c is equal to or larger than the threshold value change time, the velocity threshold value change flag 12b is set to OFF. Since the value of the threshold value change time is 5,000, and the electrostatic capacitance sensor process is performed every 100 μsec, a time during which the velocity threshold value change flag 12b is ON is a maximum of 0.5 seconds. In the striking detection process to be described below, if the velocity threshold value change flag 12b is ON, the threshold value of the value of the velocity memory 12a for producing a musical sound becomes larger. Therefore, it is possible to prevent production of a musical sound due to impact on the struck surface 2 according to choke playing. In addition, since the threshold value of the value of the velocity memory 12a for producing a musical sound returns to its original value after 0.5 seconds, it is possible to reduce a feeling of discomfort in the subsequent play operation to a minimum. Here, the value of the threshold value change time may be set to 5,000 or more or 5,000 or less as long as no feeling of discomfort is given in the play operation.

When the value of the electrostatic capacitance sensor output value memory 12h is equal to or larger than the velocity change threshold value (No in S21), 0 is stored in the velocity threshold value changing counter 12c, and the processes of S22 to S24 are skipped. That is, since the value of the electrostatic capacitance sensor output value memory 12h is equal to or larger than the velocity change threshold value, it indicates that the human body is away from the electrostatic capacitance sensor 5. Therefore, 0 is stored in the velocity threshold value changing counter 12c to prepare a case in which the human body approaches the electrostatic capacitance sensor 5 next time.

After the processes of S24 and S25, it is checked whether the value of the electrostatic capacitance sensor output value memory 12h is smaller than the electrostatic capacitance sensor detection threshold value (for example, 790) (S26). When the value of the electrostatic capacitance sensor output value memory 12h is smaller than the electrostatic capacitance sensor detection threshold value (Yes in S26), a value obtained by subtracting the value of the electrostatic capacitance sensor output value memory 12h from the electrostatic capacitance sensor detection threshold value is stored in the electrostatic capacitance sensor value memory 12i (S27). That is, a difference between the electrostatic capacitance sensor detection threshold value and the value of the electrostatic capacitance sensor output value memory 12h is stored in the electrostatic capacitance sensor value memory 12i. Based on the electrostatic capacitance sensor value memory 12i, in the choke process in FIG. 5(b), attenuation control of a musical sound that is being produced is performed.

On the other hand, when the value of the electrostatic capacitance sensor output value memory 12h is equal to or larger than the electrostatic capacitance sensor detection threshold value (No in S26), 0 is stored in the electrostatic capacitance sensor value memory 12i (S28). After the processes of S27 and S28, the electrostatic capacitance sensor process ends, and the process returns to the periodic process in FIG. 3(a).

Returns to FIG. 3(a). After the electrostatic capacitance sensor process (S2) is performed, the edge sensor process (S3) is performed. Details of the edge sensor process will be described with reference to FIG. 5(a). FIG. 5(a) is a flowchart of the edge sensor process. In the edge sensor process, a sensor value of the edge sensor 4 used in the choke process in FIG. 5(b) is calculated from an output value of the edge sensor 4, and is stored in the edge sensor value memory 12f. First, the output value of the edge sensor 4 is acquired and is stored in the edge sensor output value memory 12e (S30). When the edge sensor 4 is in an “ON” state, “1” is stored in the edge sensor output value memory 12e, and when the edge sensor 4 is in an “OFF” state, “0” is stored.

After the process of S30, it is checked whether the value of the edge sensor output value memory 12e is “1” (S31). When the value of the edge sensor output value memory 12e is “1” (Yes in S31), that is, when the edge sensor 4 is in an “ON” state, it is checked whether the edge sensor detection waiting counter 12g is equal to or larger than a detection waiting time (for example, 500, that is, 0.05 seconds) (S32). When the edge sensor detection waiting counter 12g is equal to larger than the detection waiting time (Yes in S32), 1 is set in the edge sensor value memory 12f (S34). On the other hand, when the edge sensor detection waiting counter 12g is shorter than the detection waiting time (No in S32), 1 is added to the edge sensor detection waiting counter 12g (S33), and 0 is set in the edge sensor value memory 12f (S36).

Since the value of the detection waiting time is 500, and the edge sensor process is performed every 100 μsec, when the “ON” state of the edge sensor 4 continues for 0.05 seconds or longer, 1 is set in the edge sensor value memory 12f. This is to prevent unintended choke playing due to chattering of the edge sensor 4 or the like. When the “ON” state of the edge sensor 4 continues for 0.05 seconds, since it can be determined that the “ON” state is stable, 1 is set in the edge sensor value memory 12f at this time. Therefore, after the output value of the edge sensor 4 is stabilized, since the ON/OFF state of the edge sensor 4 used in choke playing is determined (that is, the value of the edge sensor value memory 12f is changed), unintended choke playing can be prevented.

In the process of S31, when the value of the edge sensor output value memory 12e is not “1” (No in S31), 0 is set in the edge sensor detection waiting counter 12g (S35), and 0 is set in the edge sensor value memory 12f (S36). That is, since the edge sensor 4 is in an OFF state, 0 is set in the edge sensor detection waiting counter 12g to prepare a case in which the edge sensor 4 is turned on ON next time. After the processes of S34 and S36, the edge sensor process ends, and the process returns to the periodic process in FIG. 3(a).

Returns to FIG. 3(a). After the edge sensor process (S3) is performed, the choke process (S4) is performed. In the choke process, an attenuation process is performed on a musical sound that is being produced according to the value of the edge sensor value memory 12f and the value of the electrostatic capacitance sensor value memory 12i.

First, a choke setting value is calculated from the value of the edge sensor value memory 12f and the value of the electrostatic capacitance sensor value memory 12i and is stored in the choke setting value memory 12j (S40). Specifically, a result obtained by weighting the value of the edge sensor value memory 12f and the value of the electrostatic capacitance sensor value memory 12i is stored in the choke setting value memory 12j. The weighting operation is expressed by the following equation 1.

[Math. 1]

Value_CK=Value_ED*Coef_ED+Value_CS*Coef_CS Equation (1)

Here, Value_CK is a choke setting value. Value_ED is a value of the edge sensor value memory 12f. Value_CS is a value of the electrostatic capacitance sensor value memory 12i. Coef_ED and Coef_CS are weighting components for the value of the edge sensor value memory 12f and the value of the electrostatic capacitance sensor value memory 12i. Coef_ED is “64”, and Coef_CS is “0.9.” According to the weighting computation in Equation 1, a choke setting value according to the value of the edge sensor value memory 12f and the value of the electrostatic capacitance sensor value memory 12i is calculated and the choke setting value is used in an attenuation process for a musical sound that is being produced.

After the process of S40, attenuation control according to the value of the choke setting value memory 12j is performed on an arbitrary musical sound that is being produced (S41). After the process of S41, the choke process ends, and the process returns to the periodic process in FIG. 3(a). The periodic process ends after the choke process (S4) is performed.

Next, the striking detection process will be described with reference to FIG. 3(b). FIG. 3(b) is a flowchart of the striking detection process. In the striking detection process, when the striking sensor 3 detects that the struck surface 2 is struck, a striking position and a velocity are calculated from the output value of the striking sensor 3 and a musical sound according to the striking position and the velocity is produced. In addition, according to the ON/OFF state of the velocity threshold value change flag 12b, a magnitude of the velocity at which a musical sound is produced, that is, the threshold value of striking detection, is changed. The striking detection process is performed according to an interrupting process triggered by the fact that the striking sensor 3 detects striking.

First, a velocity and a striking position are calculated from the output value of the striking sensor 3 and stored in the velocity memory 12a and the striking position memory 12d (S5). Specifically, the waveform of the output value of the striking sensor 3 is analyzed, its striking strength (velocity) and a striking position (a distance from the center of the struck surface 2) are estimated, and stored in the velocity memory 12a and the striking position memory 12d.

After the process of S5, it is checked whether the velocity threshold value change flag 12b is ON (S6). When the velocity threshold value change flag 12b is ON (Yes in S6), it is checked whether the value of the velocity memory 12a is larger than the striking threshold value (for example, 10) (S7). When the value of the velocity memory 12a is larger than the striking threshold value (Yes in S7), a musical sound according to the value of the velocity memory 12a and the value of the striking position memory 12d is produced (S8). On the other hand, when the value of the velocity memory 12a is equal to or lower than the striking threshold value (No in S7), the process of S8 is skipped. That is, when a human body approaches the electrostatic capacitance sensor 5 and during the threshold value change time (0.5 seconds), if the value of the velocity memory 12a is larger than the striking threshold value, a musical sound is produced and if the value of the velocity memory 12a is equal to or smaller than the striking threshold value, no musical sound is produced.

In the process of S6, when the velocity threshold value change flag 12b is not ON (No in S6), the process of S7 is skipped and a musical sound according to the value of the velocity memory 12a and the value of the striking position memory 12d is produced (S8). After the processes of S7 and S8, the striking detection process ends.

According to the electronic cymbal 1 of the first embodiment, when striking on the struck surface 2 is detected by the striking sensor 3, production of a musical sound is controlled according to the detection result. While the musical sound is being produced, for example, when the user touches the struck surface 2, an output value corresponding to the contact state is output from the electrostatic capacitance sensor 5 and attenuation control of a musical sound that is being produced is performed according to the output value. Therefore, according to the contact state of the user with respect to the struck surface 2, it is possible to perform attenuation control of a musical sound that is being produced. Therefore, it is possible to realize a musical sound mute process according to an operation similar to choke playing in an acoustic cymbal in which the user touches the struck surface 2.

In addition, in this method, the struck surface 2 is interposed between the electrode 5a of the electrostatic capacitance sensor 5 and the user, and approach of the user's hand is detected according to change in the output value of the electrostatic capacitance sensor 5. Therefore, even when the user touches the struck surface 2 in which the electrode 5a of the electrostatic capacitance sensor 5 is not disposed, the touch is detected by the electrode 5a disposed near the position touched by the user, it is possible to perform attenuation control of a musical sound that is being produced.

When it is detected that the user's hand approaches the struck surface 2 according to the output value of the electrostatic capacitance sensor 5, a threshold value for striking detection by the striking sensor 3 is changed to a value (that is, the striking threshold value) higher than a general threshold value. Therefore, even if impact occurs on the struck surface 2 due to quick choke playing, in such a case, the threshold value of the velocity for producing a musical sound by the striking sensor 3 is changed to a value higher than the general threshold value. Therefore, it is possible to prevent erroneously detecting such a choke operation as striking.

The electrode 5a of the electrostatic capacitance sensor 5 is disposed between the struck surface 2 and the disk-shaped plate disposed on the side opposite to the struck surface 2. Therefore, the appearance of the struck surface 2 is not impaired by the electrode 5a. In addition, since it is possible to avoid direct striking of the electrode 5a, it is possible to prevent deterioration of durability of the electrode 5a.

In addition, the electrode 5a is configured as two electrodes 5a1 and 5a2 disposed on the outer circumferential side and the inner circumferential side, and these are connected to each other to form one electrode 5a. Therefore, it is possible to reduce a difference between output values of the electrostatic capacitance sensor 5 when the struck surface 2 is choked with the palm of the hand and when the struck surface 2 is gripped lightly and choked. Therefore, it is possible to recognize that “the hand touched,” in both choke operations,” that is, it is possible to recognize both choke operations and it is possible to perform attenuation control of a musical sound that is being produced.

In addition, the electrode 5a1 on the outer circumferential side and the electrode 5a2 on the inner circumferential side are formed in different areas. Therefore, since the output value of the electrostatic capacitance sensor 5 is different between when the user touches the outer circumferential side (end side) of the struck surface 2 and when the user touches the inner circumferential side of the struck surface 2, it is possible to recognize the touches distinctly. Therefore, it is possible to perform attenuation control of a musical sound that is being produced according to a touched part.

Next, a second embodiment of the present invention will be described with reference to FIGS. 6 to 9(a) and 9(b). In the above first embodiment, approach of the human body is detected by one electrostatic capacitance sensor 5, the choke process is performed according to the output value of the electrostatic capacitance sensor 5, and a threshold value for striking detection by the striking sensor 3 is changed. In the second embodiment, with two electrostatic capacitance sensors 5 and 6, the choke process is performed and a threshold value for striking detection by the striking sensor 3 is changed. In the second embodiment, parts the same as those in the above first embodiment will be denoted with the same reference numerals and descriptions thereof will be omitted.

FIG. 6 is a diagram showing the electrostatic capacitance sensors 5 and 6 of the second embodiment. As shown in FIG. 6, the electrode 5a of the electrostatic capacitance sensor 5 is disposed on the outer circumferential side of the struck surface 2. In addition, an electrode 6a of the second electrostatic capacitance sensor 6 is disposed on the inner circumferential side of the struck surface 2. The electrode 5a and the electrode 6a are formed in a single line. In addition, since the configurations of the electrostatic capacitance sensor 5 and the second electrostatic capacitance sensor 6 are the same as that of the electrostatic capacitance sensor 5 of the first embodiment, descriptions thereof will be omitted. In the electronic cymbal 1 of the second embodiment, approach of the human body on the outer circumferential side of the struck surface 2 is detected by the electrostatic capacitance sensor 5, and approach of the human body on the inner circumferential side of the struck surface 2 is detected by the electrostatic capacitance sensor 6.

FIG. 7 is a block diagram showing an electrical configuration of an electronic cymbal 100 of the second embodiment. The electronic cymbal 100 includes the CPU 10, the ROM 11, the RAM 12, the striking sensor 3, the edge sensor 4, the electrostatic capacitance sensor 5, the second electrostatic capacitance sensor 6, and the sound source 13, and these are connected to one another via the bus line 16. The amplifier 14 is connected to the sound source 13, and the speaker 15 is connected to the amplifier 14.

The RAM 12 is a memory in which various types of work data, flags and the like used when the CPU 10 executes a program such as the control program 11a are stored in a rewritable manner. In the RAM 12, the velocity memory 12a, the velocity threshold value change flag 12b, the velocity threshold value changing counter 12c, the striking position memory 12d, the edge sensor output value memory 12e, the edge sensor value memory 12f, the edge sensor detection waiting counter 12g, the electrostatic capacitance sensor output value memory 12h, the electrostatic capacitance sensor value memory 12i, the choke setting value memory 12j, a second electrostatic capacitance sensor value memory 12k, and a second velocity threshold value changing counter 12l are provided.

The second electrostatic capacitance sensor value memory 12k is a memory in which a sensor value of the second electrostatic capacitance sensor 6 calculated based on the electrostatic capacitance sensor output value memory 12h is stored. When power is supplied to the electronic cymbal 100 or in a second electrostatic capacitance sensor process in FIGS. 9(a) and 9(b), if the value of the electrostatic capacitance sensor output value memory 12h is equal to or larger than an electrostatic capacitance sensor detection threshold value, the state is set to “0” indicating that the second electrostatic capacitance sensor 6 is not detected (FIG. 9(a), S98). In the second electrostatic capacitance sensor process in FIGS. 9(a) and 9(b), when the value of the electrostatic capacitance sensor output value memory 12h is smaller than the electrostatic capacitance sensor detection threshold value, a value obtained by subtracting the value of the electrostatic capacitance sensor output value memory 12h from the electrostatic capacitance sensor detection threshold value is stored in the second electrostatic capacitance sensor value memory 12k (FIG. 9(a), S97). According to the result obtained by computing the value of the second electrostatic capacitance sensor value memory 12k, the value of the electrostatic capacitance sensor value memory 12i, and the value of the edge sensor value memory 12f, attenuation control of a musical sound that is being produced is performed.

The second velocity threshold value changing counter 12l is a counter that measures a duration time for which the velocity threshold value change flag 12b is ON according to the state of the second electrostatic capacitance sensor 6. When power is supplied to the electronic cymbal 100 or in the second electrostatic capacitance sensor process in FIGS. 9(a) and 9(b), if the value of the electrostatic capacitance sensor output value memory 12h is equal to or larger than the velocity change threshold value, “0” is set (FIG. 9(a), S95). When the value of the electrostatic capacitance sensor output value memory 12h is smaller than the velocity change threshold value, 1 is added to the second velocity threshold value changing counter 12l (FIG. 4, S93). That is, when the velocity threshold value change flag 12b is changed from OFF to ON, 1 is periodically added to the value of the second velocity threshold value changing counter 12l. The velocity threshold value change flag 12b is turned OFF when the value of the second velocity threshold value changing counter 12l is equal to or larger than the threshold value change time.

Next, a control program executed by the CPU 10 in the electronic cymbal 100 of the second embodiment will be described with reference to FIG. 8 and FIGS. 9(a) and 9(b). FIG. 8 is a flowchart of the periodic process. First, the velocity threshold value change flag 12b is set to OFF (S1), and the electrostatic capacitance sensor process (S2) is performed. After the process of S2, the second electrostatic capacitance sensor process (S9) is performed. The second electrostatic capacitance sensor process will be described with reference to FIG. 9(a).

FIG. 9(a) is a flowchart of the second electrostatic capacitance sensor process. In the second electrostatic capacitance sensor process, an output value of the second electrostatic capacitance sensor 6 is acquired, and it is determined whether or not to change a threshold value of the striking detection by the striking sensor 3 according to the output value of the second electrostatic capacitance sensor 6. In addition, a sensor value of the second electrostatic capacitance sensor 6 used in the choke process in FIG. 5(b) is calculated from the output value of the second electrostatic capacitance sensor 6, and is stored in the second electrostatic capacitance sensor value memory 12k.

First, in the second electrostatic capacitance sensor process, the output value of the second electrostatic capacitance sensor 6 is stored in the electrostatic capacitance sensor output value memory 12h (S90). After the process of S90, it is checked whether the value of the electrostatic capacitance sensor output value memory 12h is smaller than the velocity change threshold value (S91). When the value of the electrostatic capacitance sensor output value memory 12h is smaller than the velocity change threshold value (Yes in S91), it is checked whether the second velocity threshold value changing counter 12l is smaller than the threshold value change time (S92). When the second velocity threshold value changing counter 12l is shorter than the threshold value change time (Yes in S92), 1 is added to the second velocity threshold value changing counter 12l (S93), and the velocity threshold value change flag 12b is set to ON (S94). On the other hand, when the second velocity threshold value changing counter 12l is equal to or larger than the threshold value change time (No in S92), the processes of S93 to S94 are skipped.

When the value of the electrostatic capacitance sensor output value memory 12h is equal to or larger than the velocity change threshold value (No in S91), 0 is stored in the second velocity threshold value changing counter 12l, and the processes of S92 to S94 are skipped. That is, since the value of the electrostatic capacitance sensor output value memory 12h is equal to or larger than the velocity change threshold value, it indicates that the human body is away from the second electrostatic capacitance sensor 6. Therefore, 0 is stored in the second velocity threshold value changing counter 12l to prepare a case in which the human body approaches the second electrostatic capacitance sensor 6.

After the processes of S94 and S95, it is checked whether the value of the electrostatic capacitance sensor output value memory 12h is smaller than the electrostatic capacitance sensor detection threshold value (S96). When the value of the electrostatic capacitance sensor output value memory 12h is smaller than the electrostatic capacitance sensor detection threshold value (Yes in S96), a value obtained by subtracting the value of the electrostatic capacitance sensor output value memory 12h from the electrostatic capacitance sensor detection threshold value is stored in the second electrostatic capacitance sensor value memory 12k (S97). That is, a difference between the electrostatic capacitance sensor detection threshold value and the value of the electrostatic capacitance sensor output value memory 12h is stored in the second electrostatic capacitance sensor value memory 12k. Based on the second electrostatic capacitance sensor value memory 12k, in a second choke process in FIG. 9(b), attenuation control of a musical sound that is being produced is performed.

On the other hand, when the value of the electrostatic capacitance sensor output value memory 12h is equal to or larger than the electrostatic capacitance sensor detection threshold value (No in S96), 0 is stored in the second electrostatic capacitance sensor value memory 12k (S98). After the processes of S97 and S98, the second electrostatic capacitance sensor process ends, and the process returns to the periodic process in FIG. 8.

Returns to FIG. 8. After the second electrostatic capacitance sensor process (S9) is performed, the edge sensor process (S3) is performed. After the process of S3, the second choke process (S10) is performed. In the second choke process, an attenuation process is performed on a musical sound that is being produced according to the value of the edge sensor value memory 12f, the value of the electrostatic capacitance sensor value memory 12i, and the value of the second electrostatic capacitance sensor value memory 12k.

First, a choke setting value is calculated from the value of the edge sensor value memory 12f, the value of the electrostatic capacitance sensor value memory 12i, and the value of the second electrostatic capacitance sensor value memory 12k, and is stored in the choke setting value memory 12j (S100). Specifically, a result obtained by weighting the value of the edge sensor value memory 12f, the value of the electrostatic capacitance sensor value memory 12i, and the value of the second electrostatic capacitance sensor value memory 12k is stored in the choke setting value memory 12j. The weighting operation is expressed by the following equation 2.

[Math. 2]

Value_CK=Value_ED*Coef_ED+Value_CS*Coef_CS+Value_CS2*Coef_CS2 Equation(2)

Here, Value_CK is a choke setting value. Value_ED is a value of the edge sensor value memory 12f. Value_CS is a value of the electrostatic capacitance sensor value memory 12i. Value_CS2 is a value of the second electrostatic capacitance sensor value memory 12k. Coef_ED, Coef_CS, and Coef_CS2 are weighting components for the value of the edge sensor value memory 12f, the value of the electrostatic capacitance sensor value memory 12i, and the value of the second electrostatic capacitance sensor value memory 12k. Coef_ED is “64,” Coef_CS is “0.45,” and Coef_CS2 is “0.45.” According to the weighting computation in Equation 2, a choke setting value according to the value of the edge sensor value memory 12f, the value of the electrostatic capacitance sensor value memory 12i, and the value of the second electrostatic capacitance sensor value memory 12k is calculated, and the choke setting value is used in an attenuation process for a musical sound that is being produced.

After the process of S100, attenuation control according to the value of the choke setting value memory 12j is performed on an arbitrary musical sound that is being produced (S101). After the process of S101, the choke process ends, and the process returns to the periodic process in FIG. 8. The periodic process ends after the second choke process (S10) is performed.

According to the electronic cymbal 100 of the second embodiment, since the electrostatic capacitance sensor 5 is disposed on the outer circumferential side of the struck surface 2 and the second electrostatic capacitance sensor 6 is disposed on the inner circumferential side of the struck surface 2, it is possible to distinctly determine whether the user's hand approaches the outer circumferential side or the inner circumferential side of the struck surface 2. Therefore, musical sound attenuation control can be changed according to the position on the struck surface 2 in which the user touches with the two electrostatic capacitance sensors 5 and 6.

While the present invention has been described above with reference to the embodiments, the present invention is not limited to the above embodiments, and it can be easily understood that various improvements and modifications can be made within a range without departing from the spirit and scope of the present invention.

In the first embodiment, the electrode 5a of the electrostatic capacitance sensor 5 has a configuration in which the thick electrode 5a1 is disposed on the outer circumferential side and the thin electrode 5a2 is disposed on the inner circumferential side. However, the electrode 5a is not necessarily limited to such a shape, and other shapes can be appropriately used. For example, as shown in FIG. 10, the electrode 5a may be configured with only the electrode 5a1 on the outer circumferential side without the electrode 5a2 on the inner circumferential side. When the electrode 5a is formed in a single line in this manner, the electrode can be easily produced.

In addition, as shown in FIGS. 11(a)˜11(j) and FIGS. 12(a)˜12(c), the electrode 5a of the electrostatic capacitance sensor 5 may be formed. As shown in FIGS. 11(a)˜11(j), examples of other shapes of the electrode 5a include a shape in which the electrode 5a is disposed in the shape of “spider's web” (perforated shape) (FIG. 11(a)), a shape in which the electrode 5a is disposed in the shape of “mesh” (FIG. 11(c)), a shape in which holes are provided at equal intervals in the electrode 5a (perforated shape) (FIG. 11(e)), a shape in which the electrode 5a is provided radially from the center (a plurality of lines) (FIG. 11(g)), and a shape in which arcs of the plurality of electrodes 5a are connected in the shape of “one stroke” (a plurality of lines) from the inner circumferential side to the outer circumferential side (FIG. 11(i)). In addition, the electrode 5a is not limited to a semicircular shape and it may be an entire circular shape. FIG. 11(b), FIG. 11(d), FIG. 11(f), FIG. 11(h), and FIG. 11(j) are entire circular shapes of FIG. 11(a), FIG. 11(c), FIG. 11(e), FIG. 11(g), and FIG. 11(i).

Since the electrode 5a of the electrostatic capacitance sensor 5 is formed in a plurality of lines, a mesh shape, or a perforated shape, it is possible to reduce a difference between output values of the electrostatic capacitance sensor 5 when the struck surface 2 is choked with the palm of the hand and when the struck surface 2 is gripped lightly and choked. Therefore, it is possible to recognize that “the hand touched,” in both choke operations,” that is, it is possible to recognize both choke operations and it is possible to perform attenuation control of a musical sound that is being produced.

In addition, in FIG. 11(a) to FIG. 11(j), the electrode may have a shape with different areas on the inner circumferential side and the outer circumferential side. Accordingly, since the output value of the electrostatic capacitance sensor 5 is different between when the user touches the outer circumferential side (end side) of the struck surface 2 and when the user touches the inner circumferential side of the struck surface 2, it is possible to recognize the touches distinctly. Therefore, it is possible to perform attenuation control of a musical sound that is being produced according to a touched part.

In the first embodiment, a configuration in which a thick electrode is disposed on the outer circumferential side and a thin electrode is disposed on the inner circumferential side is used. However, as shown in FIGS. 12(a) and 12(b), the thickness of the electrode 5a of the electrostatic capacitance sensor 5 may be the same on the outer circumferential side and the inner circumferential side.

In addition, in the first embodiment, approach of the human body is detected by one electrostatic capacitance sensor 5. In the second embodiment, approach of the human body is detected by two of the electrostatic capacitance sensor 5 and the second electrostatic capacitance sensor 6. However, the present invention is not necessarily limited thereto, as shown in FIG. 12(c), in addition to the outer circumferential side and the inner circumferential side, an electrostatic capacitance sensor is additionally provided therebetween, and a choke operation may be detected by a total of three electrostatic capacitance sensors. In this case, a process in which a sensor value of the third electrostatic capacitance sensor is acquired, and the velocity threshold value change flag 12b is turned ON or OFF according to the sensor value (that is, a process corresponding to the second electrostatic capacitance sensor process) and a process in which musical sound attenuation control including a sensor value of the third electrostatic capacitance sensor is performed (that is, a process corresponding to the second choke process) are added. Here, of course, a choke operation may be detected by four or more electrostatic capacitance sensors.

In the present embodiment, the electronic cymbals 1 and 100 have been described as an electronic percussion instrument including an electrostatic capacitance sensor. However, the present invention is not necessarily limited thereto, and may be applied to other electronic percussion instruments. As an example, an electronic drum pad 20 shown in FIGS. 13(a)˜13(c) is exemplified.

FIG. 13(a) is a front view of the electronic drum pad 20 of a modified example. FIG. 13(b) is a cross-sectional view of the electronic drum pad 20 in the XIIIb part in FIG. 13(a). FIG. 13(c) is a schematic view of the electronic drum pad 20 in the XIIIc part in FIG. 13(b). A rubber struck surface 21 is disposed at the center of the electronic drum pad 20. A steel plate 22 is disposed below the struck surface 21, and the electrostatic capacitance sensor 5 is disposed between the struck surface 21 and the steel plate 22. A striking sensor 23 is disposed below the steel plate 22. The striking sensor 23 is a piezoelectric sensor for detecting striking. When the user strikes the struck surface 21, the impact is transmitted to the striking sensor 23 through the steel plate 22 and the striking is detected. A musical sound is produced according to the detection result. However, when it is determined that the struck surface 21 is touched with a hand, the musical sound that is being produced is muted (silenced).

In an electronic drum pad including no electrostatic capacitance sensor 5 of the related art, when striking is repeated, static electricity (that is, electric charge) accumulates in the vicinity of the struck surface 21 and the steel plate 22. When this static electricity is transmitted to the striking sensor 23, a sound source (not shown) connected to the striking sensor 23 may malfunction or be erroneously operated. In order to prevent this, the steel plate 22 is grounded, and thus static electricity in the vicinity of the struck surface 21 and the steel plate 22 is omitted. Here, the electrostatic capacitance sensor 5 can repeatedly send electric charges. Therefore, in the electronic drum pad 20 of this modified example, when the electrostatic capacitance sensor 5 is superimposed on the steel plate 22, since electric charges accumulated in the steel plate 22 are also periodically sent, and accumulation of electric charges does not continue, it is not necessary to ground the steel plate 22. Therefore, it is possible to reduce the number of components of the electronic drum pad 20.

Here, in this modified example, a configuration in which the electrostatic capacitance sensor 5 is superimposed on the steel plate 22 is used. However, a configuration in which the steel plate 22 is used as the electrode 5a of the electrostatic capacitance sensor 5 may be used.

In the present embodiment, a choke operation is recognized according to detection results of the edge sensor 4, the electrostatic capacitance sensor 5, and the second electrostatic capacitance sensor 6. However, the present invention is not necessarily limited thereto, and a configuration in which the edge sensor 4 is not provided and a choke operation is recognized using only the electrostatic capacitance sensor 5 and the second electrostatic capacitance sensor 6 may be used. In this case, the edge sensor output value memory 12e, the edge sensor value memory 12f, and the edge sensor detection waiting counter 12g are unnecessary. In addition, execution of the edge sensor process in FIG. 5(a) is not necessary. In this case, in S40 of the edge sensor process in FIG. 5(b) and S100 of the second edge sensor process in FIG. 9(b), Coef_CS and Coef_CS2, that is, weighting component values for the value of the electrostatic capacitance sensor value memory 12i and the value of the second electrostatic capacitance sensor value memory 12k, may be appropriately changed.

	Number	Date	Country
Parent	16330372	Mar 2019	US
Child	17842807		US

ELECTRONIC PERCUSSION INSTRUMENT AND SOUND PRODUCTION CONTROL METHOD THEREOF

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