Detection device, percussion instrument and a method

Abstract

The invention relates to a detection device for sensing vibrations in a drum or other percussion instrument, the device including: a thin film piezoelectric sensor; a supporting arm holder that can be located on the percussion instrument. The piezoelectric sensor is attached to the supporting arm and a flexible free end of the piezoelectric sensor extends outwardly from the supporting arm for contacting a head of the percussion instrument so that vibration of the head can cause the flexible free end to oscillate, and thereby generate an output signal from the piezoelectric sensor for generating sound electronically.

Description

DescriptionTitle of Invention : DETECTION DEVICE, PERCUSSION INSTRUMENT AND A METHOD |Technical Field

[0001] The present disclosure relates to a detection device, a percussion instrument such as drum, and a detection method.Background Art

[0002] Acoustic drums are often considered ‘beautiful’ but any one acoustic drum only produces sound according to its physical features, size, materials, tuning and the room in which its played, and the loud volume of sound from acoustic drumming is often considered a problem that limits when, where and how a drum can be played. Electronic drums (Edrums) allow much quieter play and are designed to sense percussion instrument impacts to trigger electronic sounds that can be played in headphones or speakers at a quiet volume. Whilst there are some devices that can be retro-fitted to existing drums to enable percussion instrument impact vibrations to be detected, the low sensitivity of the devices to strikes on the head (i.e., the skin) of the drum can be problematic and is difficult to control due to a number of factors. It is often also important to distinguish between drum head sounding events and rim or shell sounding events as discussed in US5977473 PTL1. The dynamic vibrations of drum heads can be complex as discussed at length by Torin NPL1 and leading acoustic drum manufacturers adopt a general guiding principal of “Nothing Inside the Shell; Nothing Through the Shell” in order to obtain maximum shell resonance as discussed in Shimada and Komiya NPL2 which is often at odds with the complex and substantial internal constructions of conventional electronic drums as described in PTL2 US10147409.

[0003] It is an object of the present disclosure to provide an alternative detection device that can be used for sensing vibrations in the head of the drum or other percussion instrument for generating sound electronically to enable theinstrument to be played as an acoustic, electronic or a combination thereof musical instrument.Summary of Invention

[0004] An embodiment of the present invention relates to a detection device for a percussion instrument, the device including: a thin film piezoelectric sensor; a supporting arm that can be attached to the percussion instrument, wherein the piezoelectric sensor is attached to the supporting arm and a flexible free end of the piezoelectric sensor extends outwardly from the supporting arm for contacting a head of the percussion instrument so that vibration of the head can cause the flexible free end to oscillate, and thereby generate an output signal from the piezoelectric sensor.

[0005] The amplitude and frequency of the output signal, which is generated by the free end oscillating based on the vibration of the head, can be used to electrically generate sound corresponding to the percussion instrument.

[0006] It will be understood by the skilled artisan that the flexible fee end of the piezoelectric sensor will be sufficiently flexibility to detect by not interference with the impact vibrations of the percussion instrument.

[0007] For instance, the magnitude of the vibration of the head is represented by the amplitude of the output signal. That is, as the magnitude of the vibration of the head increases, for example during loud play, deflection of the piezoelectric sensor also increases and the amplitude of the output signal increases. Similarly, the period of the vibration of the head is represented by the frequency of the output signal, which is based on the period of oscillation of free end.

[0008] One of the benefits of the device is that oscillation of the flexible free end of the piezoelectric sensor causes a high deflection in the flexible free end toward, or adjacent to, an attachment site where the piezoelectric sensor is attached to the holder which provides a responsive output signal. Moreover, the inventor has discovered that the output signal has superior signal quality and practical utility in terms of amplitude, differentiation between clear signal and noise signal, anddistinct early peaks in the output signal for various strength hits of the percussion instrument. Thereby enabling the output signal to be used to generate different sounds, including sounds of the different loudness and tones. In addition, the percussion instrument can be used as a hybrid in which acoustic sound and electronic sound are combined, or alternatively the output signals can be captured without electronic sounds being generated in real-time. In the later situation, the output signal can be captured for later analysis and / or instrument sonic augmentation.

[0009] In one example, the supporting arm can be attached to the percussion instrument. For example, the supporting arm can be attached to a shell of a drum, such as the side of the shell. In another example, the supporting arm can be attached between a rim of the shell and the head of the instrument.

[0010] In one example, the supporting arm may be resiliently flexible. One of the benefits this provides is that larger vibrations or movement of the head in contact with the piezoelectric sensor can cause the support arm to move away from the vibrating head. Although it is possible that the vibrating head could contact and directly move the supporting arm, ideally the supporting arm moves in response to load being applied to the piezoelectric sensor which is in turn applied to the supporting arm.

[0011] The supporting arm may be moveably mounted to the percussion instrument. For instance, the supporting arm may be pivotally connected to the percussion instrument. Preferably a biasing object biases the supporting arm in a direction toward a vibrating head of the percussion instrument so that the supporting arm is movable against the biasing.

[0012] In one example, the supporting arm may be less flexible than the flexible free end of the piezoelectric sensor.

[0013] In another example, the supporting arm may have the same flexibility as the flexible free end of the piezoelectric sensor.

[0014] The supporting arm may have a cantilever structure. The supporting arm may have a length to locate the piezoelectric sensor at a distance from a perimeter of the percussion instrument. The distance may be any suitable distance based on the size of the percussion such as base drum, tom tom drum or a snare drum.

[0015] The supporting arm may have a length that locates the piezoelectric sensor at a spacing in the range of 15mm to 50mm from the perimeter of the percussion instrument. Suitably, the range may be from 20 to 30mm and even more suitably in the range of 25mm from the perimeter. One of the advantages of locating the piezoelectric sensor at this spacing is that the device can be used for any sized drum, such as 6 to16 inch drums, and base drums including 16 to 24 inch bass drums.

[0016] In one example, the holder may have a rigid body to which the piezoelectric sensor can be attach. For example, the attachment site of the holder may be a slot into which the piezoelectric sensor is frictionally received. In another example, the piezoelectric sensor may be adhered to the rigid body. The device can be used for percussion instruments that do not have outer shell such as roto tom drums. In this example, the rigid body of the holder may be attached directly to the frame structure of the roto tom drum beneath the surface of the drum and the piezoelectric sensor can extend upward toward the vibrating substrate of the percussion instrument.

[0017] The flexible free end of the piezoelectric sensor may have a substantially planar structure.

[0018] The flexible free end of the piezoelectric sensor may form an acute angle (e.g. less than 90° or less than 60° or less than 45°) with the head of the percussion instrument. The acute angle being viewed in a direction toward a shell or outer perimeter of the drum of the percussion instrument.

[0019] In one example, the flexible portion of the piezoelectric sensor may form an obtuse angle with the supporting arm. The piezoelectric sensor may extend along the supporting arm at the attachment site. The obtuse angle between the sensor and head allows flexing and in turn enhanced sensitivity of the sensor than if the sensor was arranged tangentially to the head.

[0020] The piezoelectric sensor and supporting arm may be configured to be advantageous and both increase sensitivity to a wide range of head strike forces and prevent damage to the head, with the relative flexibility of the supporting arm to the piezoelectric sensor only resulting in movement of the supporting arm at a predetermined downward force. A further advantage of being configured in thisway is that reliable instrument play can be achieved for many different head tension tunings across a wide range of drum sizes.

[0021] In another example, the flexible portion of the piezoelectric sensor may form an acute angle with the supporting arm.

[0022] In yet another example, the flexible portion of the piezoelectric sensor may form a right angle with the supporting arm.

[0023] The device may have a mounting for attaching the device to the percussion instrument. The mounting may include any one or a combination of: a clamp, a plate with adhesive, a fastener point such as an opening for a fastener such as a screw or bolt, a hanging formation such a hook that fits over an upper edge of a wall of the drum and so forth.

[0024] The flexible portion of the piezoelectric sensor extending outwardly of the holder may be a free portion that is unsupported. In one example, the flexible portion may extend beyond the holder by a length in the range of 3 to 15mm, and suitably by a length in the range of 3 to 10mm, and even more suitably by a length in the range of 3 to 7mm.

[0025] The output signal may have a latency from the head being struck by a period from 300 to 1000 microseconds, and suitably from 300 to 500 microseconds, and suitably from 60 to 100 microseconds.

[0026] The present invention also relates to a percussion instrument including: a head of the instrument can be struck to cause vibration thereof; a thin film piezoelectric sensor; a supporting arm that can be attached to the percussion instrument, wherein the piezoelectric sensor is attached to the supporting arm and a flexible free end of the piezoelectric sensor extends outwardly from the supporting arm for contacting a head of the percussion instrument so that vibration of the head can cause the flexible free end of the piezoelectric sensor to oscillate, and thereby generate an output signal from the piezoelectric sensor.

[0027] That is say, the amplitude of an output signal of the piezoelectric sensor increases as the deflection of the piezoelectric sensor increases. In other wordsvibration of the head can cause the flexing portion to oscillate and as deflection of the piezoelectric sensor increases the amplitude of the output signal from the piezoelectric sensor can increase enabling the amplitude of the output signal to represent loudness of music to be generated from the output signal.

[0028] The percussion instrument may include any one or combination of the features of the detection device described herein.

[0029] Another embodiment of the present invention relates to a detection device for a percussion instrument, the device including: a sensor; and a flexible arm to which the disc piezoelectric sensor is attached, and the flexible arm being configured so that when attached to the percussion instrument the piezoelectric sensor can contact the head of the percussion instrument and movement of the head applies a load to the piezoelectric sensor which in turn cause the flexible arm to move in response to movement of the head, and the piezoelectric sensor can generate an output signal based on the load applied.

[0030] The sensor may be a disc piezoelectric sensor such as a ceramic disc piezoelectric, or an inertia sensor such as 3 dimensional surface mounted accelerometer sensor.

[0031] The sensor may be a combination of a disc piezoelectric sensor and an inertial sensor.

[0032] An embodiment of the present invention relates to a method of detection vibrations of a percussion instrument, the method including: providing a detection device including a supporting arm and a thin film piezoelectric sensor attached to the supporting arm, the piezoelectric sensor having a flexible free end extending outwardly from the supporting arm; attaching the detection device to the percussion instrument so that the flexible free end portion contacts a head of the percussion instrument; receiving an output signal from the piezoelectric sensor that is generated by vibration the head causing the flexible free end of the piezoelectric sensor to oscillate.

[0033] The method described herein may include any one or a combination of the features of the detection device or the percussion instrument described herein.

[0034] An embodiment relates to a drum head and the detection device including any one or a combination of the features described herein, in which the sensor is bonded to the drum head. Similarly, another embodiment relates to a drum head and the detection device including any one or a combination of the features described herein, in which the supporting arm is bonded to the drum head.Brief Description of Drawings

[0035] A preferred embodiment of the present invention will now be described with reference to the accompanying drawings which can be summarised as follows.Fig.1

[0036] Figure 1 is a schematic cross-sectional view of a drum shell, drum head and detection device fitted to the drum that is contacting an underneath side of the drum head.Fig.2

[0037] Figure 2 is a schematic cross-sectional view of the upper portion shown in Figure 1 in which the detection device is in a relaxed position and the drum head is represented in a relaxed non-vibrating position. A cross symbol has been provided to provide a frame of reference for showing the position of the detection device.Fig.3

[0038] Figures 3 and 4 are schematic cross-sectional views that are the same as Figure 2 in which the detection device is located in different operating positions. Specifically, Figure 3 shows a situation in which the drum head is in moderate deflection representing the head has been struck with a light to moderate strength hit and in which an outer end of the detection device has deflected in response, and a holder portion of the device has not moved or only moved to a small extent.Fig.4

[0039] Figure 4 shows a situation in which the drum head is in a large deflection representing the head has been struck with a strong hit and in which the outer end of the detection device has deflected considerably and the holder portion has moved down and to the left in response.Fig.5

[0040] Figure 5 is a graph illustrating an output signal from the detection device with the output signal having a small amplitude with a soft strike and the output signal having a large amplitude with the strongest strike.Fig.6

[0041] Figure 6 is graph illustrating the output signal from another detection device over the same strike intensity using the same drum for the very same hit sequence. As can be seen the output signals are significantly less pronounced.Fig.7

[0042] Figure 7 is a closeup view of the first 2500 microseconds of the output signal from Figure 5.Fig.8

[0043] Figures 8 is photograph of a drum shell including a detection device according to another example in which the drum head has been removed.Fig.9

[0044] Figure 9 is schematic drawing of apart cut drum showing a detection device according to yet another example located inside of the drum head.Description of Embodiments

[0045] A cross-section of part of a percussion instrument, such as a drum 10, is illustrated in Figure 1 and includes a shell 11 , lug 12, a hoop rim13 , head frame 14 and tensioning rod 15 for tensioning the drum head, hereinafter referred to as the head 16, and a detection device 17. The detection device 17 can be retrofitted to existing drums or installed on drum 10 at manufacture. For example, the detection device 17 can be fitted to an acoustic drum that is played acoustically with conventional mylar heads / skins, or fitted to a drum played with low volume mesh heads. In either case, the detection device 17 can be used to generate sounds electronically. In addition, the percussion instrument can be used as a hybrid in which acoustic sound and electronic sound are combined, or alternatively the output signals can be captured without electronic sounds being generated in real-time. In the later situation, the output signal can be captured for later analysis and / or instrument sonic augmentation.

[0046] The detection device 17 includes a holder / supporting arm18 and a piezoelectric sensor 19 (also referred herein as a sensor) being attached to the supporting arm 18 and flexible free end of the sensor extending from the supporting arm 18. The piezoelectric sensor 19 is ideally a thin film vibration sensor that has a resiliently flexible body. An example of a suitable piezoelectric sensor is the vibration sensor commercially available from TE Connectivity under the label LDT1-028K. This sensor 19 has a total length of approximately 41.5 mm, a width of approximately 16.3mm, and a thickness of approximately 0.2mm including a sensor layer and outer protective mylar layers. That is to say, the sensor 19 has a laminated structure of functional layers supported on a substrate. The sensor 19 is substantially flat planar when relaxed. The sensor 19 is attached to the supporting arm 18 at an attachment site 23 which may comprise any suitable attachment. The supporting arm 18 is configured to maintain contact between the free end of the sensor 19, or at least the substrate on which the sensor 19 is laminated and the head 16 of the drum 10 whilst the head 16 is vibrating, or for as long as possible whilst the head 16 is vibrating. The detection device 17 also includes a mounting piece 20, which in Figure 1 comprises a plate having an opening through a fastener such as lug screw 21 is received and connects to a lug 12 on the outside of the shell 11. The sensor 19includes leads 22 that can be connected to an audio connector port 25 such as a jack, plug or other transmitting device for transmission of an output signal from the sensor 19. The signals from the sensor 19 can be passed by conventional conductive signal paths (e.g. printed conductive paths, and / or wiring / cabling, etc) from the sensor 19 to the audio connector port 24 and so on to conventional drum sound modules such as those sold by Alesis, Roland and Yamaha etc where a sounds are played in response to voltage signals from the sensor 19 and the triggered sounds can then be heard through conventional sound equipment (headphones, amplified speakers) in response to drum play.

[0047] The supporting arm 18 is mounted and fitted with the sensor 19 so that the leads 22 extend freely do not interfere with sensor function to connect to a the audio connector port 24 in the shell 11 of the drum 10, or may pass through a port 25 in the drum 10 to the audio connector port 24, or in the case of a single headed drum exit out the bottom of the drum 10 to an the audio connector port 24.

[0048] Whilst Figures 1 to 4 illustrate the detection device 17 being located beneath the head 16 of the drum 10 or on the opposite side of the head 16 of the drum 10 that is being struck, it will be appreciate that the detection device 17 could be located on the same side of the head 16 being struck.Examples

[0049] In one example, the holder / supporting arm 18, as illustrated in Figures 1 to 4, which includes a stiff or resiliently flexible strip or tab, and the attachment site 23 is located toward the end of the supporting arm 18. The sensor 19 may be fixed in a co-planar arrangement at the attachment site 23. The sensor 19 may be fixed to the attachment site 23 using any suitable means including a biasing clamp, or a clamp having fasteners, or fasteners including hot or cold adhesives, a tape that wraps about the sensor 19 and the supporting arm 18, or a shrink sleeve, such as a heat shrink sleeve that contracts about the sensor 19 and the supporting arm 18 to secure the sensor 19 in position.

[0050] In one configuration, the piezoelectric sensor 19 may be attached to the supporting arm 18 so that a force sensitive portion, i.e. a sensing portion of thepiezoelectric sensor 19, is located outward from the supporting arm 18. That is to say the sensing portion of the piezoelectric sensor 19 does not extend onto the attachment site 23 or over the supporting arm itself.

[0051] In another configuration, the piezoelectric sensor 19 is attached to the supporting arm 18 so that a sensing portion of the piezoelectric sensor 19 extends outward from the end of the supporting arm 18 and extends over at least part, and suitably all of the attachment site 23. Irrespective of whether the sensing portion of the piezoelectric sensor 29 is located on the attachment site 23 or not, deflection and deformation of the flexible piezoelectric sensor 19 is greatest adjacent to the end of the supporting arm 18.

[0052] The sensor 19 may extend a distance E from the end of the supporting arm 18 by a length in the range of 1 to 10mm and suitably approximately 2 to 3mm. Ideally, the detection device 17 can be arranged so that a straight end or edge of the sensor 19 abuts against the drum head 16 and the body of the sensor 19 is arranged at an angle C to the drum head 16, for example, an acute angle or an obtuse angle. It will be appreciated that the end or edge of the sensor 19 may not be straight or linear. For instance, the straight end or edge of the sensor 19 may have a curved, undulating profile. Although not illustrated in the Figures, the sensor 19 extending outwardly from the supporting arm 18 may include one or more fold or crease when in the relaxed state.

[0053] The supporting arm 18 may have a length to locate the sensor 19 on the head 16 at a distance D in the range of the 15 to 40mm from a perimeter of the head 16 and suitably in the range of the 20 to 35mm, and even more preferably in the range of 25 mm from the perimeter. One of the benefits of the present device is that it works effectively for a broad range of drums sizes, including 6 to 16 inch drums, such as snare drums, tom toms, and tambourines, and bass drums including 16 to 24 inch bass drums.

[0054] The supporting arm 18 may be made of any lightweight polymeric materials, e.g. polypropylene, mylar, spring steel, and so forth. In one example, the supporting arm 18 may be made of mylar and have a width in the range of the 10 to 25mm, and suitably 20mm, a length in the range of the 20 to 80mm, and a thickness in the range of 0.5 to 2mm. The mounting piece 20 may also be madeof similar materials, and the supporting arm may flex and / or pivot relative to the mounting piece 20. It is also possible that the supporting arm 18 may be fixedly attached to the mounting piece 20 so as be form a cantilever from the mounting piece 20. In any event, the supporting arm 18 may deflect by a smaller amount than the sensor 19 when subject to the same load. That is to say, the supporting arm 19 may have higher stiffness than the stiffness of the sensor 19.

[0055] As mentioned above the supporting arm 18 may be stiff, in which case the supporting arm 18 is ideally pivotally connected to the device 10 and the stiff supporting arm 18 can move against a biasing means which urges the stiff supporting arm 18 against the head 16 so that the sensor 19 is able to maintain contact with the vibrating head 16.

[0056] The supporting arm 18 may be resiliently flexible in which case the supporting arm 18 has a configuration to allow the sensor 19 to maintain contact with the vibrating head 16. In either situation, the attachment site 23 is able to move relative to the percussion instrument as a result of vibration of the head 16.

[0057] In another example, the sensor 19 may be bonded to a drum head 16. One of the benefits provided by the sensor 19 being bonded to the head 16 is that a user can swap out or replace the drum head 16 in the normally way and using the sensor 19 attached to the head 16 as a guide on where to position the head 16 on the drum shell 11. Likewise, the supporting arm 18 can be bonded to the drum head 16, the head frame 14, or the shell 11. The supporting arm 18 can be bonded to the drum head 16, the head frame 14 or the shell 11 instead of, or in addition to, the sensor 19 being bonded to the drum head 16.

[0058] Figures 2 to 4 illustrate the drum head 16 at varying states of vibration resulting from different strikes. Specifically, Figure 2 illustrates the situation in which the head 16 has not been struck where the sensor 19 extends from the support arm 18 attachment site 23 at location O. As can be seen the sensor 19 maintains contact the underside of the head 16. In another embodiment, not illustrated, the sensor 19 can be displaced by a small gap, for example up to 2 mm, from the head 16 when the head has not been struck, or when at rest. The small gap can mean that small or incidental hits on the head 16 can be missed.

[0059] Figure 3 illustrates the situation in which the head 16 of the drum 10 is struck with a moderate force which deforms the head 16 whilst it vibrates, causing the sensor 19 to deflect along the length of the sensor 19 extending from supporting arm 18, but also notably the sensor 19 will under maximum deflection adjacent to the supporting arm 18. As can be seen the sensor 19 maintains contact the underside of the head and the support arm 18 and attachment site 23 remain at location O.

[0060] Figure 4 illustrates another situation in which the head 16 of the drum 10 is struck with considerable force which deforms the head 16 to a greater extent than in Figure 3 and the support arm 18 and attachment site 23 move away from location O. In Figure 3, the sensor 19 can deflect along the length of the sensor 19 extending from the supporting arm 18, and the sensor 19 can undergo maximum deflection adjacent to the supporting arm 18. In this situation, as can be seen, the supporting arm 18 moves which may, for example, be provided by either one or a combination or flexing of the supporting arm 18, or pivoting of the supporting arm 18 relative to the mounting piece 25 from which the supporting arm 18 extends. As can be seen the sensor 19 maintains contact the underside of the head 16.

[0061] By allowing the supporting arm 18 to the move in this manner, both the sensor 19 and supporting arm 18 are able to move as a cantilever subject to the forced applied to the sensor 19 through striking of the head 16. This allows the detection device 17 to operate in a manner that preferentially detects the drum head 16 vibrations generated by being struck as opposed to vibrations in a shell 11 or rim 13 through taps, knocks which are dampened out by the moving supporting arm 18. That is, the supporting arm 18 and sensor 19 act to effectively dampen vibrations and isolate the piezoelectric sensor 19 relative to the shell 11 so that only impacts to the drum head 16 cause significant excitation signals from the piezoelectric sensor 19. This is advantageous because drum head 16 events are detected with greater specificity compared to hoop / rim and shell vibrations and other kit vibrations and so also reduces cross talk between drum elements. It will be appreciated that cross talk occurs when a drum is hit, aspects of the force and / or vibrations are transferred to other drums throughdrum mounts and supports (not illustrated) resulting in inappropriate sounding of another drum such as can happen when tom toms are mounted on a bass drum.

[0062] In use, it is preferred that the piezoelectric sensor 19 maintain contact through biasing action of the supporting arm 18 and the configuration of the supporting arm 18.

[0063] The supporting arm 18 can be shaped, positioned and made from materials (such as light weight polymeric materials, e.g. polypropylene, mylar, etc) to effectively isolate the drum head vibration activity from drum rim and shell activity. As can be seen in Figure 1 , the supporting arm 18 and the sensor 19 are arranged in a parallel relationship. However, it will be appreciated that the supporting arm 18 and the sensor 19 may be angled at an obtuse angle or an acute. The angle can help maintain the straight end of the sensor 19 in contact with the head 16. Moreover, the device 17 may include means for adjusting the sensor 19 location and angle, and enable a subtle force to be exerted on the device 17 to maintain contact with the head 16, e.g. enough to contact and possibly slightly pre-deflect the sensor 19 and / or the supporting arm 18 in a manner so that very light drum hits cause an electric excitation signal from the piezoelectric sensor 19.

[0064] In one example, the supporting arm 18 may have one or more folds or creases in the support arm 18. The supporting arm 18 may have a linear configuration, or a non-linear configuration, including a S-shape, Z-shape, L- shape, V-shape and so forth. For example, Figure 1 show the supporting arm 18 having an obtuse A, and another obtuse angle B between the supporting arm 18 and the mounting piece 20. In this way the piezoelectric sensor 19 is directed at the drum head at an angle C so that the piezoelectric sensor 19 deflects when the drum head is struck.

[0065] In another example, the holder may have a rigid body (not illustrated) that has no moving components to which the sensor 19 is attached. Although not illustrated in the Figures, the rigid body may include an attachment site 23 in much the same manner as the supporting arm and the sensor may be fixed to the attachment site 23 using any suitable means, including a clamp, adhesive, tape, adhesives and so forth as mentioned above with reference to the supporting arm.An example of the clamp includes a friction fitting slot into which the sensor is located.

[0066] In one situation, the rigid body may be mounted to a structural frame located below the percussion surface or drum head, such as roto toms. In another situation, the rigid body may be mounted to the shell of the percussion shell.

[0067] In the situation where the holder has a rigid body that is substantially not moving, the sensor may have longer flexible free end portion, for example in the range of 10 to 20mm.

[0068] Figures 5 and 6 illustrate comparison data, in which Figure 5 comprises data obtained using the preferred detection device 17 described above and shown in Figure 1 . The comparison test setup used a 13” Tama Swingstar Tom Tom in which the detection device was set up on the inside upper edge of the shell. The comparison device was a worked example of the embodiment shown in embodiment 5c described in United States patent publication US20220148548A1 by Roland Corp, the results of which are shown in Figure 6. The sensors were connected to an Alesis DM10 for signal-to-MIDI conversion and in parallel also routed to a Digitech002 mixer with equal gain staging for each sensor with data simultaneous MIDI and sensor signals captured at 44100Hz in ProTools 8 Digital Audio Workstation software. Audio .wav files were converted to text .txt files using Goldwave software and imported into Microsoft Excel to enable comparative analysis which included manual identification of a common time zero for each event so as to allow direct comparison of various hits and sensors. The drum was stuck with a 7AN type drumstick fitted with a piezo disc sensor (which was also logged) with 5 consecutive hits of increasing force.

[0069] As can be seen in Figure 5, the present detection device provided superior signal quality and practical utility in terms of amplitude, signal to noise, and distinct early peaks, for various strength hits.

[0070] This exemplary performance was evident across a wide range of drum sizes and the sensor was demonstrated to work well with an assortment of existing drum modules (e.g. Drum products Roland TD27, Roland TD17, Alesis DM10, Alesis Nitro, Alesis Strike, 2Box Drumlt5 Mkl I, EDruminlO).

[0071] It will be appreciated that the results shown in Figures 5, 6 and 7, and indeed the signal outputs can be influenced by a number of factors, including drum head type, drum head tension, location of the sensor, location of head strike, type of drumstick, force of strike, and drummer technique. Moreover, the characteristics of the output signals including frequency and amplitude will vary due to drummer set up, preferences, and module circuitry such as rectified signal with capacitance smoothing and / or digital filtering. By way of example, output signal transduction time through or across mesh head varied by ~ + / -1ms subject to strike location, thus indicating that the location of the strikes on the head had a large influence over the latency.

[0072] One of the benefits of the present device is that the output signal retains a characteristic shape for a particular drum size and tensioning for very soft and very hard drum strikes. This is useful in that the force by which the drum is struck can be determined very quickly from the initial excitation of the sensor. For instance, as can be seen in the Figure 7, which is an enlarged view of the first 2500 microseconds of the output signal of Figure 5, initial striking of the head can be detected within 1000 microseconds, and suitably within 500 microseconds, and suitably within 300 microseconds, and even more suitably within 100 microseconds. This represents a reduced latency in the output signal.

[0073] Overall this early detection peak can enable improved strike location detection (such as may be done with three sensors using triangulation methods in more complex drum simulation). The sensor described herein has shown promise to function robustly with diverse implementations and drum hitting approaches.

[0074] It will be appreciated that many modifications and variations may be made to the preferred embodiment without departing from the spirit and scope of the invention.

[0075] Although not illustrated, if the sensor is constructed using a longer printed flexible element, then it can be arranged to pass under the head and over the shell rim, before connecting through to an audio plug. When a thin longish sensor is used (such as LDT2) the Arm may be fixed to a drum head or have a surface that freely rests against the shell and head and the sensor can exit under drum head and above shell. It is envisaged that any connections near thedrumhead frame often need to be electrically insulated and the drumhead frame provides a location to fix or hook the sensor to the drum so as to maintain arm location and sensor pressure against the head. Reference Signs List

[0076] Reference Numeral Table

[0077] Reference Letter TableCitation List

[0078] Helmer, R.J.N. (2024). DETECTION DEVICE, PERCUSSION INSTRUMENTAND A METHOD. Australian Provisional Patent Application AU 2024903604Patent Literature

[0079] PTL1 : US5977473

[0080] PTL2: US10147409

[0081] PTL3: US20220148548A1Non Patent Literature

[0082] NPL1 : Alberto Torin, Percussion Instrument Modelling In 3D: Sound Synthesis Through Time Domain Numerical Simulation, Doctor of Philosophy, University of Edinburgh 2016. Retrieved from < https: / / www.albertotorin.it / files / ATorin_PhDThesis.pdf >

[0083] NPL2: Mitsuaki Shimada, Katsuaki Komiya, The History Of Tama Drums 1965-2020, pg 29. Retrieved from < https: / / www.hoshinogakki.co.jp / pdf / tama / catalog / TAMA_historyBook.pdf >

Claims

Claims

1. A percussion instrument including: a head of the instrument can be struck to cause vibration thereof; a thin film piezoelectric sensor; a supporting arm that can be attached to the percussion instrument, wherein the piezoelectric sensor is attached to the supporting arm and a flexible free end of the piezoelectric sensor extends outwardly from the holder for contacting a head of the percussion instrument so that vibration of the head can cause the flexible free end of the piezoelectric sensor to oscillate, and thereby generate an output signal from the piezoelectric sensor.

2. The percussion instrument of claim 1 , wherein the supporting arm is pivotally connected to the percussion instrument.

3. The percussion instruction of claim 1 or 2, wherein the support arm forms a cantilever structure.

4. The percussion instrument of any one of the preceding claims, wherein a biasing object biases the supporting arm in a direction toward a vibrating head of the percussion instrument so that the supporting arm is movable against the biasing.

5. The percussion instrument of any one of the preceding claims, wherein the piezoelectric sensor forms an acute angle with the head of the percussion instrument.

6. The percussion instrument of any one of the preceding claims, wherein the piezoelectric sensor forms an obtuse angle with the supporting arm.

7. The percussion instrument of claims 5 and 6, wherein the piezoelectric sensor and the supporting arm are configured to enhance sensitivity of the sensor compared to the sensor arranged tangentially to the head.

8. A detection device as defined according to any one of the preceding claims.

9. A detection device for a percussion instrument, the device including: a thin film piezoelectric sensor; a supporting arm holder that can be attached to the percussion instrument, wherein the piezoelectric sensor is attached to the supporting arm and a flexible free end of the piezoelectric sensor extends outwardly from the supporting arm for contacting a head of the percussion instrument so that vibration of the head can cause the flexible free end to oscillate, and thereby generate an output signal from the piezoelectric sensor.

10. The detector device of claim 9, wherein the piezoelectric sensor forms an obtuse angle with the supporting arm.

11. The detector device of claim 9 or 10, wherein the supporting arm is less flexible than the flexible free end of the piezoelectric sensor.

12. A method of detection vibrations of a percussion instrument, the method including: providing a detection device including a supporting arm and a thin film piezoelectric sensor attached to the supporting arm, the piezoelectric sensor having a flexible free end extending outwardly from the holder; attaching the detection device to the percussion instrument so that the flexible free end portion contacts a head of the percussion instrument; receiving an output signal from the piezoelectric sensor that is generated by vibration the head causing the flexible free end of the piezoelectric sensor to oscillate.

13. A detection device for a percussion instrument, the device including: a sensor; and a flexible arm to which the disc piezoelectric sensor is attached, and the flexible arm being configured so that when attached to the percussion instrument the piezoelectric sensor can contact the head of the percussion instrument and movement of the head applies a load to thepiezoelectric sensor which in turn cause the flexible arm to move in response to movement of the head, and the piezoelectric sensor can generate an output signal based on the load applied.

14. A drum head and the detection device, in which the sensor is bonded to the drum head.

15. A drum head and the detection device, in which the supporting arm of the detection device is bonded to the drum head.

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