WO2016110774A1

WO2016110774A1 - Systems, devices, and methods for encoding music

Info

Publication number: WO2016110774A1
Application number: PCT/IB2015/060037
Authority: WO
Inventors: Calvin LAW
Original assignee: Cardinote Inc.
Priority date: 2015-01-05
Filing date: 2015-12-29
Publication date: 2016-07-14

Abstract

There is disclosed a device for encoding music played using a stringed instrument. The device includes at least one magnet for providing a magnetic field proximate each of a plurality of strings of the stringed instrument; a plurality of Hall effect sensors, each paired with one of the plurality of strings and configured to generate a signal reflective of changes in the magnetic field caused by vibrations of the paired string; and a signal processor configured to process the signals generated by the plurality of Hall effect sensors to encode data reflective of music played using the stringed instrument.

Description

SYSTEMS, DEVICES, AND METHODS FOR ENCODING MUSIC

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001 ] This disclosure claims priority to United States Provisional Patent Application No. US 62/099,765, filed January 5, 2015, and entitled "SYSTEMS, DEVICES, AND METHODS FOR ENCODING MUSIC", the entirety of which is hereby incorporated by reference in its entirety.

FIELD

[0002] This disclosure relates to musical instruments, and more particularly to encoding of music played using a musical instrument. INTRODUCTION

[0003] The Musical Instrument Digital Interface (MIDI) standard and digital audio workstations (DAW) are tools that are commonly used by music producers. Producers typically use MIDI instruments to record their performances, which are then edited inside DAW software. Unlike traditional instruments that record sound, MIDI instruments record musical events such as note onsets and durations. Besides the immediate benefit of simplified audio manipulation, a MIDI stream can also be used to trigger synthesizer sounds and generate music notation in real-time.

[0004] The most common MIDI instrument is a musical keyboard. The keyboard fits very well with the MIDI model since each key is uniquely mapped to a pitch. The processing of key presses takes zero latency and is simple to implement. As a result, MIDI recording has typically been reserved for those familiar with the piano.

[0005] Some MIDI guitars are also available. Typically, MIDI guitars are provided by fitting a transducer near or directly on each of the strings, and then processing the output of those transducers to generate musical metadata. Such transducers are commonly coiled magnetic pickups or piezo sensors. Piezo sensors must be in contact with the string to sense vibrations. Installation of piezo sensors on existing guitars thus requires heavy modification. Coiled magnetic pickups do not suffer from this limitation, as they are designed to sense the vibrating string remotely. However, the remote sensing range is limited by sensor size. Coiled pickups comprise a length of wire wrapped around a permanent magnet. In general, a coil with more turns and a stronger magnet result in improved sensing range. But in practice, it is undesirable or impractical to fit a large coil and magnet due to string clearances on the instrument. Hence, the sensor must still be very close to the string to facilitate downstream processing. This, too, complicates the installation procedure on existing guitars, for example, the sensors must be precisely placed, e.g., to be sufficiently close to the strings. It may be difficult to achieve precise sensor placement due to various guitar body sizes and string clearances.

[0006] Accordingly, a new, improved, and/or alternative solution is desired for overcoming at least some of the above-noted shortfalls.

SUMMARY

[0007] In accordance with one aspect, there is provided a device for encoding music played using a stringed instrument. The device includes at least one magnet for providing a magnetic field proximate each of a plurality of strings of the stringed instrument; a plurality of Hall effect sensors, each paired with one of the plurality of strings and configured to generate a signal reflective of changes in the magnetic field caused by vibrations of the paired string; and a signal processor configured to process the signals generated by the plurality of Hall effect sensors to encode data reflective of music played using the stringed instrument. [0008] In accordance with another aspect, there is provided a method for encoding music played using a stringed instrument. The method includes: generating a magnetic field proximate each of the plurality of strings of the stringed instrument; disposing a plurality of Hall effect sensors, each associated with one of the plurality of strings; sensing the magnetic field caused by vibrations of particular ones of the plurality of strings, using the plurality of Hall effect sensors; generating signals reflective of the sensed magnetic field; and encoding data reflective of music played using the stringed instrument by processing the signals.

[0009] In accordance with another aspect, there is provided a device for retrofitting a stringed instrument to encode music played using the instrument. The device includes: at least one magnet; a plurality of Hall effect sensors; a mount for mounting the device on the stringed instrument such that the at least one magnet provides a magnetic field proximate each of a plurality of strings of the stringed instrument, and such that each of the plurality of Hall effect sensors is disposed adjacent a string of the stringed instrument to generate a signal reflective of magnetic field changes caused by vibrations of that string; and a signal processor configured to process the signals generated by the plurality of Hall effect sensors to encode data reflective of music played using the stringed instrument.

[0010] In accordance with another aspect, there is provided a method of modifying a stringed instrument to encode music. The method includes: attaching at least one magnet to the stringed instrument, the at least one magnet adapted to provide a magnetic field proximate each of a plurality of strings of the stringed instrument; attaching a plurality of Hall effect sensors to the stringed instrument, each paired with one of the plurality of strings and configured to generate a signal reflective of changes in the magnetic field caused by vibrations of the paired string; and providing a signal processor configured to process the signals generated by the plurality of Hall effect sensors to encode data reflective of music played on the stringed instrument.

[001 1 ] In accordance with another aspect, there is provided a kit comprising: a stringed instrument comprising a plurality of magnetically permeable strings and a device mountable to the stringed instrument. The device includes: at least one magnet for providing a magnetic field proximate each of the plurality of strings, when the device is mounted to the stringed instrument; a plurality of Hall effect sensors, each for pairing with one of the plurality of strings and configured to generate a signal reflective of changes in the magnetic field caused by vibrations of the paired string, when the device is mounted to the stringed instrument; and a signal processor configured to process the signals generated by the plurality of Hall effect sensors to encode data reflective of music played on the stringed instrument. [0012] In accordance with another aspect, there is provided a stringed instrument comprising: a plurality of magnetically permeable strings; at least one magnet for providing a magnetic field proximate each of the plurality of strings; a plurality of Hall effect sensors, each paired with one of the plurality of strings and configured to generate a signal reflective of changes in the magnetic field caused by vibrations of the paired string; and a signal processor configured to process the signals generated by the plurality of Hall effect sensors to encode data reflective of music played on the stringed instrument.

[0013] In accordance with another aspect, there is provided a device for sensing music played using a stringed instrument. The device includes: at least one magnet for providing a magnetic field proximate each of a plurality of strings of the stringed instrument; a plurality of Hall effect sensors, each paired with one of the plurality of strings and configured to generate a signal reflective of changes in the magnetic field caused by vibrations of the paired string; and a data transmission interface for transmitting the generated signals to an interconnected device. [0014] In accordance with another aspect, there is provided a system for encoding music played using a stringed instrument. The system includes: a sensing device comprising: at least one magnet for providing a magnetic field proximate each of a plurality of strings of the stringed instrument; and a plurality of Hall effect sensors, each paired with one of the plurality of strings and configured to generate a signal reflective of changes in the magnetic field caused by vibrations of the paired string; and a processing device connectable to the sensing device, the processing device comprising: a signal processor configured to process the signals generated by the plurality of Hall effect sensors to encode data reflective of music played using the stringed instrument.

[0015] Many further features and combinations thereof concerning embodiments described herein will appear to those skilled in the art following a reading of the instant disclosure.

DESCRIPTION OF THE FIGURES

[0016] FIG. 1 is a schematic diagram of an example encoding device for encoding music played using a stringed instrument, and an interconnected computing device, exemplary of an embodiment.

[0017] FIG. 2 is a perspective view of the encoding device of FIG. 1 , exemplary of an embodiment. [0018] FIG. 3 is a perspective view of the encoding device of FIG. 1 and a part of a stringed instrument, exemplary of an embodiment.

[0019] FIG. 4 is a perspective view of a sensor module of the encoding device of FIG. 1 , exemplary of an embodiment. [0020] FIG. 5 is a perspective view of a sensor module of the encoding device of FIG. 1 , exemplary of an embodiment.

[0021 ] FIG. 6 is a schematic diagram of a conditioning module of the encoding device of FIG. 1 , exemplary of an embodiment.

[0022] FIG. 7 is a circuit diagram of the conditioning module of the encoding device of FIG. 1 , exemplary of an embodiment.

[0023] FIG. 8 is graph of a sample signal processed at the encoding device of FIG. 1 , exemplary of an embodiment.

[0024] FIG. 9 is a high-level block diagram of hardware components of the encoding device of FIG. 1 , exemplary of an embodiment. [0025] FIG. 10 is a perspective view of a printed circuit board of the encoding device of FIG. 1 , exemplary of an embodiment.

[0026] FIG. 11 is a bottom plan view of the encoding device of FIG. 1 , exemplary of an embodiment.

[0027] FIG. 12 is a schematic diagram of an encoding system for encoding music played using a stringed instrument, exemplary of an embodiment.

DETAILED DESCRIPTION

[0028] FIG. 1 schematically illustrates an example encoding device 100 configured to encode data reflective of music played using a stringed instrument, exemplary of an embodiment. As illustrated, device 100 may be interconnected with a computing device 200 configured to receive the encoded data. [0029] Device 100 includes a plurality of sensor modules 102-1 , 102-2, ... 102-n configured to sense music being played at a stringed instrument. These sensor modules may be referred to individually as a sensor module 102 and collectively as sensor modules 102. As detailed below, each sensor module 102 includes an analog Hall effect sensor configured to detect changes in a magnetic field caused by vibration of a magnetically permeable string of the stringed instrument, and provides an analog signal representative of sensed magnetic field changes.

[0030] Conveniently, in the depicted embodiment, the use of Hall effect sensors alleviates the need for tight coupling between the sensors and the instrument's strings. For example, it is not necessary for sensors to be fitted in contact with the strings, as may be required when using piezo sensors. Similarly, it is not necessary for sensors to be precisely placed relative to the strings, as may be required when using coiled magnetic pickups.

[0031 ] Further, Hall effect sensors have a significantly broader magnetic range (e.g., +/- 600 Gauss) compared to certain other types of solid-state sensors such as magneto- resistance sensors (e.g.,. AMR, GMR, or TMR sensors). Consequently, in the depicted embodiment, the use of Hall effect sensors allows magnets of a broader range of strengths to be used as part of sensor modules 102.

[0032] Further, Hall effect sensors have a concentrated field sensing range of operation. Consequently, in the depicted embodiment, the use of Hall effect sensors allows sensor module 102 to focus on magnetic field changes caused by a particular string, thereby reducing crosstalk from nearby strings.

[0033] Further, the use of Hall effect sensors in the depicted embodiment may provide sensor signals of sufficient strength to allow reliable detection of music events (including pitch) at the instrument, thereby reducing occurrence of false triggers and unwanted artifacts.

[0034] Device 100 also includes a plurality of conditioning modules 104-1 , 104-2, ... 104- n configured to condition sensor signals from sensor modules 102. These conditioning modules may be referred to individually as a conditioning module 104 and collectively as conditioning modules 104. For example, conditioning modules 104 may be configured to amplify and/or to apply filters to analog signals from sensor modules 102. In this way, when a weak/noisy signal is received from a sensor module 102, it may be conditioned to be suitable for digitization and encoding in manners described herein. For example, signals from sensor modules 102 may be filtered to remove noise and/or amplified to improve the signal-to-noise ratio (SNR) of the signals. In an embodiment, conditioning modules 104 may be omitted, e.g., when signal conditioning is not required or is performed exclusively on digital signals, or when digital Hall effect sensors are used in sensor modules 102.

[0035] The number of sensor modules 102 and the number of conditioning modules 104 may each correspond to the number of strings of the stringed instrument, and may each be paired with a particular one of the strings to sense and condition signals for a paired string. Alternatively, each sensor modules 102 and each conditioning module 104 may also be configured, respectively, to sense and condition signals for multiple strings of the stringed instrument. [0036] Device 100 also includes a processing module 106 configured to process sensor signals and encode data reflective of music played using a stringed instrument. As shown, processing module 106 includes at least one analog-to-digital converter (ADC) 108, at least one digital filter 110, and at least one pitch detector 112.

[0037] Each analog to digital converter (ADC) 108 is configured to convert an analog sensor signal to a digital signal. In the depicted embodiment, ADC 108 receives analog signals from conditioning modules 104. In an embodiment, ADC 108 receives analog signals from sensor modules 102, e.g., when conditioning modules 104 are omitted.

[0038] Each digital filter 110 is configured to filter the digitized output of ADC 108. Digital filtering may be performed on the digitized sensor signals to further improve the SNR of those signals. In an embodiment, each digital filter 110 implements at least one infinite impulse response (MR) filter. For example, an MR filter may be implemented as difference equations. In an embodiment, each digital filter 110 implements at least one finite impulse response (FIR) filter. In an embodiment, each digital filter 110 implements a combination of MR and FIR filters. Other suitable digital filters may also be implemented, as known to those of ordinary skill. Digital filters 110 may be excluded in some embodiment, e.g., when filtering is not required or is performed exclusively on analog signals.

[0039] Pitch detector 112 is configured to process a digitized sensor signal to perform pitch detection and encode data representative of music played at the stringed instrument. Pitch detector 110 may perform pitch detection using one or more pitch detection algorithm. Such pitch detection algorithms may include, for example, YIN, MPM, Praat, BaNa, average magnitude difference function (AMDF), harmonic product spectrum (HPS), or the like. Other pitch detection algorithms known to those of ordinary skill may also be used.

[0040] In some embodiments, the pitch detector 110 apply one or more pitch detection algorithms by finding the dominant frequency(ies) present in the received signals. In some examples, the pitch detector 110 identifies dominant frequencies that correspond to pitches perceivable by the human ear. In some embodiments, real or near real-time performance may be achieved by processing windows of incoming signals as they arrive. The pitch detector 110 analyzes the received signals using time domain, frequency domain, or mixed domain methods depending on the algorithm. In some embodiments, the algorithm may employing a zero-crossing detector in which the time lag between two successive positive or negative sloped zero crossing defines a pitch period. In some examples, low-pass filtering can be added as a pre-processing step to improve detection accuracy. Any well-known algorithm such as those listed above, a custom algorithm, or a combination of techniques can be implemented to robustly extract music data such as pitch, amplitude or loudness, changes in pitch, percussive events and the like.

[0041 ] Pitch detector 112 may encode data representative of the played music into a variety of formats suitable for playback, recording, editing, generation of music notation, etc. In an embodiment, pitch detector 112 encodes data in the MIDI format. So, the encoded data may include metadata describing musical events, e.g., describing particular notes that are played, note onsets and durations, or the like. Pitch detector 112 may also encode data in another format with metadata describing music played using an instrument. [0042] In an embodiment, data is encoded in real-time or near real-time. In an embodiment, encoded data is provided in the form of a data stream (e.g., a MIDI stream) to an interconnected device.

[0043] In an embodiment, processing module 106 may be configured to compress the encoded data for transmission (e.g., to device 200). In an embodiment, processing module 106 may be configured to process sensor data with calibration against environmental variables (e.g., humidity, temperature, etc.). In an embodiment, processing module 106 may be configured to introduce user-specified distortion effects to the encoded music.

[0044] In an embodiment, processing module 106 may be implemented using a combination of software and hardware. In an embodiment, processing module 106 may be implemented using only hardware. In an embodiment, processing module 106 may include a processor, as detailed below.

[0045] Device 100 also includes a data communication interface 114 configured to allow device 100 communicate with an interconnected computing device 200, e.g., to transmit encoded data to device 200. In an embodiment, data communication interface 114 may include one or more wired interfaces such as, e.g., a USB interface, a FireWire interface, an Ethernet interface, or the like. In an embodiment, data communication interface 114 may include one or more wireless interfaces such as, e.g., an NFC interface, a WiFi interface (e.g., an 802.1 1 interface), a Bluetooth interface, an infrared interface, or the like. In an embodiment, data communication interface 114 may include a combination of wired and wireless interfaces.

[0046] Device 100 may also receive control signals by way of a data communication interface 114. Such control signals may control the operation of device 100, e.g., to enable/disable processing at processing module 106, to configure pitch detection algorithm parameters, to configure the sample rate, to configure the method of encoding and/or encoding parameters, or the like.

[0047] Computing device 200 is configured to receive the encoded data transmitted by device 100. The encoded data may then be recorded, played back, modified, etc., at computing device 200. Computing device 200 may, for example, be a desktop computer, a laptop computer, a tablet computer, a mobile phone, a hardware synthesizer, a sequencer, or the like.

[0048] In an embodiment, device 100 may transmit encoded data to another type of device. For example, device 100 may transmit encoded data to an amplifier, speakers, etc.

[0049] FIG. 2 provides a perspective view of device 100, exemplary of an embodiment. As shown, device 100 includes a housing 140, and a connector 142. Housing 140 substantially encloses various components of device 100. Connector 142 is configured to establish one or more wired interfaces of data communication interface 114. In an embodiment in which data communication interface 114 includes solely wireless interfaces, connector 142 may be omitted.

[0050] FIG. 3 provides a perspective view of device 100 attached to a stringed instrument 300. In the depicted embodiment, instrument 300 is a guitar, which may be referred to as guitar 300. In other embodiments, device 100 may be used in conjunction with various other types of stringed instruments having vibratable magnetically permeable (e.g., metal) strings. Such other types of instruments may include, for example, harps, banjos, ukuleles, pianos, cellos, violins, violas, sitars, and double basses, or the like.

[0051 ] Device 100 may be disposed adjacent to strings 302-1 , 302-2, 302-3, 302-4, 302- 5, and 302-6 of guitar 300. These strings may be referred to individually as a string 302 and collectively as strings 302. For example, as depicted, device 100 may be disposed under strings 302 and adjacent bridge 304. So disposed, device 100 generates a magnetic field proximate each string 302, and provides a sensor module 102 adjacent each string 302 to sense changes in the magnetic field caused by vibrations of that string (e.g., as music is played using guitar 300). As noted, in an embodiment, each sensor module 102 may be paired with a particular string 302 for sensing magnetic field changes caused by that string. So, a string 302 may have a dedicated sensor module 102.

[0052] In other embodiments, device 100 may be disposed in other positions relative to instrument 300. In an embodiment, device 100 may be disposed in positions to accommodate the particular geometry of instrument 300. In an embodiment, sensor modules 102 may extend (e.g., by way of wires) from housing 140 to be adjacent strings 302 and housing 140 may be located elsewhere, spaced from strings 302 or spaced from instrument 300. [0053] FIG. 4 depicts components of a sensor module 102 paired with a string 302, exemplary of an embodiment. For clarity of illustration, other components of device 100 and guitar 300 are not shown.

[0054] As shown, sensor module 102 includes a magnet 402 and a Hall effect sensor 404, each disposed adjacent a string 302. Magnet 402 is oriented to present one pole (e.g., North or South) directed towards sensor 404, and an opposite pole directed towards string 302.

[0055] As noted, sensor module 102 need not be tightly coupled to string 302. For example, as shown, sensor module 102 does not contact string 302. Rather, sensor module 102 may be positioned such that magnet 402 is spaced approximately 1 mm to 5 mm from string 302. In some cases, sensor module 102 may be positioned such that magnet 402 is 10 mm or farther from string 302, e.g., when string 302 has a sufficiently large gauge, and magnet 402 is sufficiently strong. Sensor 404 may be positioned between string 302 and magnet 402, or positioned on a side of magnet 402 opposite string 302. As shown, sensor 404 may be positioned to be spaced from magnet 402. For example, sensor 404 may be positioned to be spaced approximately 1 mm to 5 mm from magnet 402. The distance between sensor 404 and magnet 402 may be chosen to avoid saturating sensor 404 during operation. In an embodiment, sensor 404 may be positioned to contact magnet 402.

[0056] Magnet 402 is configured to provide a magnetic field around string 302. Magnet 402 may be any type of magnet capable of generating a magnetic field including, for example, permanent magnets, electromagnets, induced magnets, ferromagnetic magnets, paramagnetic magnets, diamagnetic magnets, superconducting magnets, etc. In one specific embodiment, magnet 402 is a neodymium magnet with a surface field of approximately 2500 Gauss. [0057] Magnet 402 may have various shapes and/or geometries, such as a bar, a solenoid, a coil, etc. Magnet 402 may be a single magnet, or a plurality of magnets.

[0058] Sensor 404 is a Hall effect sensor (also known as a Hall sensor), which senses magnetic fields through the application of the Hall effect and produces an output voltage proportional to the strength of the magnet field, as sensed. In some embodiment, sensor 404 may be provided in the form of an integrated circuit. For example, in one specific embodiment, sensor 404 may be an Allegro Micro A1324 chip, a Honeywell SS49E chip, or the like.

[0059] In the depicted embodiment, as vibrations of string 302 cause fluctuations in the magnetic field around the string, the magnitude of the output voltage also fluctuates in response. In particular, when string 302 vibrates at a particular frequency, the output voltage of sensor 404 also fluctuates at the same frequency. So, sensor 404 provides an output signal reflective of changes in the magnetic field. This signal may be processed to detect a frequency of vibration of string 302, e.g., at processing module 106. [0060] In an embodiment, sensor 404 may be another type of sensor having characteristics similar to a Hall effect sensor, e.g., capable of sensing changes in a magnetic field. In an embodiment, sensor 404 may be another type of sensor that senses other characteristics of a magnetic field, such as, for example, magnetic flux density, directionality of the magnetic field, etc., and provides an output signal reflective such other characteristics. [0061 ] In the embodiment of FIG. 4, a sensor 404 is spaced from string 302 with a sensing face presented to string 302. Meanwhile, a magnet 402 is spaced from the opposite face of sensor 404.

[0062] Other arrangements of sensor 404 and magnet 402 may also be used so long as string 302 is subject to a magnet field established by magnet 402, and sensor 404 can sense changes in the magnetic field caused by vibrations of string 302, and provide signals of sufficient strength to allow downstream processing in manners disclosed herein. [0063] For example, FIG. 5 depicts an alternate arrangement, exemplary of an embodiment. In the embodiment of FIG. 5, the placement of magnet 402 and sensor 404 is reversed such that magnet 402 is interposed between sensor 404 and string 302.

[0064] In an embodiment, device 100 may include a single large magnet that spans strings 302 to generate a suitable magnetic field around each string 302. In this embodiment, each sensor module 102 need not include a separate magnet 402. Use of multiple magnets 402 (e.g., one for each string 302) may be desirable, however, to reduce crosstalk.

[0065] FIG. 6 schematically illustrates a conditioning module 104, exemplary of an embodiment. As shown, conditioning module 104 includes gain stage 604, AC coupling 606, filtering stage 608, and DC offset 610.

[0066] Gain stage 604 receives an analog sensor signal 602 from a sensor module 102, and applies amplification. So, gain stage 604 may include one or more circuit components configured to amplify a sensor signal, such as for example, operational amplifiers (op-amps), differential amplifiers, isolation amplifiers, negative feedback amplifiers, closed loop amplifier topologies, open loop amplifier topologies, or the like.

[0067] AC coupling 606 includes one or more AC-coupling circuit components configured to separate AC components from DC components of a sensor signal.

[0068] Filter stage 608 includes one or more analog filters configured to improve the signal-to-noise ratio (SNR) of a sensor signal. Such filters may include, for example, various types of low-pass, high-pass, Chebyshev, band-pass, n-stage, n-order filters, or the like.

[0069] A DC offset 610 may be applied to the sensor signal to bring the signal into an operational range of ADC 108. DC offset 610 may be omitted if not required by ADC 108.

[0070] The output of conditioning module 104 is a conditioned signal 612, which is provided to ADC 108 for digitization. [0071 ] FIG. 7 is a circuit diagram showing an example circuit 700 configured to implement conditioning module 104, exemplary of an embodiment. [0072] As shown, circuit 700 comprises resistors R1 , R2, R3 and R4, capacitors (C1 , C2 and C3), a Hall effect sensor (IC1), and an operational amplifier (IC2).

[0073] In circuit 700, a sensor signal is AC coupled before being provided into a low-noise operational amplifier with closed-loop gain (e.g., a gain of 100) and subject to a filter. As shown, the filter is a first order band-pass filter that attenuates frequencies under 20Hz and over 2000Hz. The band-pass filter may filter high frequency noise, and facilitate satisfying the Nyquist sampling criterion.

[0074] In other embodiments, a different gain value, band-pass range, multiple gain stages, or higher order filters can be used to suit a particular instrument 300 or a particular gauge of a string 302.

[0075] Conditioning of a sensor signal by conditioning module 104 increases the SNR of the sensor signal to facilitate reliable pitch detection. In an embodiment, conditioning by conditioning module 104 improves the detection range of sensor module 102, thereby avoiding or reducing a requirement for precise sensor placement relative to strings 302. [0076] The conditioned sensor signal is provided to processing module 106. As noted, processing module 106 converts the analog sensor signal to a digital signal. This digital signal may be processed to apply further conditioning, e.g., at digital filter 110. Such digital filtering may further increase the SNR of the sensor signal.

[0077] FIG. 8 is graph of a sample signal for a plucked high E string on guitar 300, following signal conditioning and digitization in manners disclosed here, exemplary of an embodiment. In FIG. 8, the y-axis is representative of pulse code modulation (PCM) amplitude, and the x-axis is representative of time. In an embodiment, this signal is processed, e.g., to perform pitch detection, and encode a MIDI representation of the plucked high E string. [0078] FIG. 9 is a high-level block diagram depicting hardware components of device 100, exemplary of an embodiment. As illustrated, device 100 includes at least one processor 902, memory 904, and at least one I/O interface 906. [0079] Each processor 902 may be any type of processor, such as, for example, any type of microprocessor or microcontroller, a digital signal processing (DSP) processor, an integrated circuit, a field programmable gate array (FPGA), a microcontroller, a reconfigurable processor, or any combination thereof. [0080] In an embodiment, the at least one processor 902 may be configured to implement digital filter 110 and/or pitch detector 112.

[0081 ] In an embodiment, the at least one processor 902 may include an integrated multichannel ADC that functions as ADC 108. In another embodiment, the at least one processor 902 and ADC 108 may be separate components, and may communicate by way of suitable protocols such as, e.g., the Inter-Integrated Circuit (l²C) protocol.

[0082] In an embodiment, multiple processors 902 may be provided such that each processor 902 is dedicated to processing sensor signals from a particular sensor.

[0083] Memory 904 may be any type of electronic memory that is located either internally or externally such as, for example, random-access memory (RAM), read-only memory (ROM), compact disc read-only memory (CDROM), electro-optical memory, magneto-optical memory, erasable programmable read-only memory (EPROM), and electrically-erasable programmable read-only memory (EEPROM), Ferroelectric RAM (FRAM) or the like.

[0084] In an embodiment, memory 904 stores code implementing one or more digital filters, and/or one or more pitch detection algorithms. In an embodiment, memory 904 provides a buffer for storing encoded data to be transmitted from device 100.

[0085] Each I/O interface 906 enables device 100 to communicate with an interconnected device, e.g., device 200. Each I/O interface 906 may implement one or more of the wired and wireless interfaces disclosed herein. So, for example, an I/O interface 906 may include a connector (e.g., connector 142 of FIG. 2) for transmitting encoded data. An I/O interface 906 may also include a wireless transmitter for transmitting encoded data.

[0086] FIG. 10 illustrates an example printed circuit board (PCB) 1000 of device 100, exemplary of an embodiment. PCB 1000 integrates various components of device 100, as disclosed herein, on a single board. PCB 1000 may be housed in housing 140, with one end of connector 142 extending through housing 140 (FIG. 2).

[0087] FIG. 10 illustrates the placement of sensor modules 102 on PCB 1000. So placed, each sensor modules 102 may be provided adjacent a string 302 when device 100 is attached to instrument 300, as shown for example in FIG. 3.

[0088] FIG. 11 shows the bottom of device 100. As shown, device 100 includes a plurality of mount points 1102 allowing device 100 to be mounted to an instrument 300. Mount points 1102 may be configured to allow device 100 to be fixedly mounted. Mount points 1102 may be configured to allow device 100 to be removably mounted. [0089] Each mount point 1102 may include a suitable fastener such as for example, an adhesive, screws, interlocking protrusions / cavities, etc.

[0090] As noted, sensor modules 102 of device 100 need not be tightly coupled to strings 302 of instrument 300. Conveniently, this allows device 100 to be mounted to instrument 300 without the use of precision instruments. Further, this allows device 100 to be mounted, removed, and re-mounted readily from instrument 300, e.g., using temporary adhesive putty.

[0091 ] The mounting points 1102 are shown as examples only; there may be a greater or fewer number of mounting points 1102 in various locations and arrangements.

[0092] Device 100 may be self-powered, e.g., by way of a battery (not shown). Device 100 may also be powered by an external power source. In an embodiment, device 100 may receive power from connector 142 to power device 100 or to recharge its battery.

[0093] In an embodiment, device 100 encodes data for transmitting to an interconnected device without performing pitch detection. In this embodiment, pitch detector 112 may be omitted. So, device 100 may encode data in a raw audio format such as, for example, the PCM format. In this embodiment, pitch detection may be performed at an interconnected device (e.g., device 200) that receives and processes the encoded data.

[0094] Device 100 may also encode data (with or without pitch detection) in a variety of other formats including, for example, Waveform Audio File Format (WAV), MP3 format, Free Lossless Audio Codec (FLAC) format, or the like. Other suitable audio data formats or metadata formats known to those of ordinary skill may also be used.

[0095] In an embodiment, device 100 may be a standalone unit that may be used in conjunction with an instrument 300. [0096] In an embodiment, device 100 may be used as a device to retrofit (e.g., by an end- user) an instrument 300 to output encoded data (e.g., MIDI data) reflective of music played at that instrument. Conveniently, as device 100 may reduce the need for tight coupling of its sensors with an instrument's strings and/or reduce the need for precise sensor placement, retrofitting may be simplified. Retrofitting may also accommodate a wide variety of instruments.

[0097] In an embodiment, device 100 may be integrated with an instrument 300, and the instrument including device 100 may be sold together as a single unit.

[0098] In an embodiment, a device 100 and an instrument 300 may be provided in a kit, with the device 100 being mountable to instrument 300, e.g., by an end-user. [0099] In an embodiment, there is provided a method for encoding music played using a stringed instrument (e.g. instrument 300) in manners similar to device 100. The method includes: generating a magnetic field proximate each of the plurality of strings of the stringed instrument; disposing a plurality of Hall effect sensors, each associated with one of the plurality of strings; sensing the magnetic field caused by vibrations of particular ones of the plurality of strings, using the plurality of Hall effect sensors; generating signals reflective of the sensed magnetic field; and encoding data reflective of music played using the stringed instrument by processing the signals.

[00100] In an embodiment, there is provided a method of modifying a stringed instrument (e.g., instrument 300) to encode music played at that instrument in manners similar to device 100. The method includes: attaching at least one magnet to the stringed instrument, the at least one magnet adapted to provide a magnetic field proximate each of a plurality of strings of the stringed instrument; attaching a plurality of Hall effect sensors to the stringed instrument, each paired with one of the plurality of strings and configured to generate a signal reflective of changes in the magnetic field caused by vibrations of the paired string; and providing a signal processor configured to process the signals generated by the plurality of Hall effect sensors to encode data reflective of music played on the stringed instrument.

[00101 ] In an embodiment, there is provided a stringed instrument configured to encode music played at that instrument in manners similar to device 100. So, the instrument may include a plurality of magnetically permeable strings; at least one magnet for providing a magnetic field proximate each of the plurality of strings; a plurality of Hall effect sensors, each paired with one of the plurality of strings and configured to generate a signal reflective of changes in the magnetic field caused by vibrations of the paired string; and a signal processor configured to process the signals generated by the plurality of Hall effect sensors to encode data reflective of music played on the stringed instrument.

[00102] FIG. 12 shows a system 1200 for encoding music played using a stringed instrument (e.g., instrument 300), exemplary of an embodiment. As shown, the system may include a sensing device 1202 and a processing device 1204. Sensing device 1202 and processing device 1204 cooperate to encode music played using a stringed instrument, in manners similar to device 100.

[00103] Sensing device 1202 may include a plurality of sensor modules 102. So, the sensing device 1202 includes at least one magnet for providing a magnetic field proximate each string 302 of instrument 300, and a plurality of sensors 404 (e.g., Hall effect sensors), each paired with one of the strings 302 and configured to generate a signal reflective of changes in the magnetic field caused by vibrations of the paired string 302. Sensing device 1202 may include a data communication interface (e.g., interface 114) configured to transmit the sensor signal to an interconnected device (e.g., processing device 1204).

[00104] In an embodiment, sensing device 1202 does not include a processing module 106. However, sensing device 1202 may be otherwise substantially similar to device 100. For example, sensing device 1202 may be mounted to an instrument 300. [00105] Processing device 1204 is connectable to sensing device 1202, and may receive the sensor signal from sensing device 1202. Processing device 1204 may connect to sensing device 1202 wirelessly, or by way of a wired connection.

[00106] Processing device 1204 includes a processing module 106 to process sensor signals received from sensing device 1202. So, processing device 1204 includes a signal processor configured to process sensor signals received from sensing device 1202 to encode data reflective of music played using the stringed instrument.

[00107] In an embodiment, each of sensing device 1202 and processing device 1204 may have an architecture as shown in FIG. 9. [00108] The foregoing discussion provides many example embodiments. Although each embodiment represents a single combination of inventive elements, other examples may include all possible combinations of the disclosed elements. Thus if one embodiment comprises elements A, B, and C, and a second embodiment comprises elements B and D, other remaining combinations of A, B, C, or D, may also be used. [00109] The technical solution of embodiments may be in the form of a software product. The software product may be stored in a non-volatile or non-transitory storage medium, which can be a compact disk read-only memory (CD-ROM), a USB flash disk, or a removable hard disk. The software product includes a number of instructions that enable a computer device (personal computer, server, or network device) to execute the methods provided by the embodiments.

[001 10] The embodiments described herein are implemented by physical computer hardware, including computing devices, servers, receivers, transmitters, processors, memory, displays, and networks. The embodiments described herein provide useful physical machines and particularly configured computer hardware arrangements. The embodiments described herein are directed to electronic machines and methods implemented by electronic machines adapted for processing and transforming electromagnetic signals which represent various types of information. The embodiments described herein pervasively and integrally relate to machines, and their uses; and the embodiments described herein have no meaning or practical applicability outside their use with computer hardware, machines, and various hardware components. Substituting the physical hardware particularly configured to implement various acts for non-physical hardware, using mental steps for example, may substantially affect the way the embodiments work. Such computer hardware limitations are clearly essential elements of the embodiments described herein, and they cannot be omitted or substituted for mental means without having a material effect on the operation and structure of the embodiments described herein. The computer hardware is essential to implement the various embodiments described herein and is not merely used to perform steps expeditiously and in an efficient manner. [001 1 1 ] Although the embodiments have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the scope as defined by the appended claims.

[001 12] Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed, that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps

[001 13] As can be understood, the examples described above and illustrated are intended to be exemplary only. For instance, there may be various computer system products, non- transitory computer readable media, apparatuses, methods contemplated. The scope is indicated by the appended claims.

Claims

WHAT IS CLAIMED IS:

1. A device for encoding music played using a stringed instrument, the device comprising:

at least one magnet for providing a magnetic field proximate each of a plurality of strings of the stringed instrument;

a plurality of Hall effect sensors, each paired with one of the plurality of strings and configured to generate a signal reflective of changes in the magnetic field caused by vibrations of the paired string; and

a signal processor configured to process the signals generated by the plurality of Hall effect sensors to encode data reflective of music played using the stringed instrument.

2. The device of claim 1 , further comprising a data transmission interface configured to transmit the encoded data.

3. The device of claim 2, wherein the data transmission interface comprises a wired interface.

4. The device of claim 3, wherein the data transmission interface comprises at least one of a USB interface, a Firewire interface, and an Ethernet interface.

5. The device of claim 2, wherein the data transmission interface comprises a wireless interface.

6. The device of claim 5, wherein the data transmission interface comprises at least one of an NFC, a Bluetooth, a WiFi, and an infrared interface.

7. The device of claim 1 , further comprising a signal conditioner configured to condition at least one of the signals generated by the plurality of Hall effect sensors.

8. The device of claim 7, wherein the signal conditioner is configured to filter the at least one of the signals.

9. The device of claim 8, wherein the signal conditioner is configured to filter the at least one of the signals to reduce noise.

10. The device of claim 7, wherein the signal conditioner is configured to amplify the at least one of the signals.

1 1 . The device of claim 7, wherein the signal conditioner is configured to distort the at least one of the signals.

12. The device of claim 1 , wherein the data is encoded in MIDI format.

13. The device of claim 1 , wherein the data is encoded in a format suitable for playback.

14. The device of claim 1 , wherein the stringed instrument is at least one of a harp, a piano, a guitar, a ukulele, a cello, a violin, a viola, a banjo, a sitar and a double bass.

15. The device of claim 1 , the signal processor is configured to process the signals by performing pitch detection.

16. The device of claim 1 , wherein the magnet comprises at least one of an electromagnet and a permanent magnet.

17. The device of claim 1 , wherein the device is positioned beneath the strings.

18. The device of claim 1 , wherein the at least one magnet includes a plurality of magnets, each for providing a magnetic field proximate a given one of the plurality of strings.

19. A method for encoding music played using a stringed instrument, the method comprising:

generating a magnetic field proximate each of the plurality of strings of the stringed instrument;

disposing a plurality of Hall effect sensors, each associated with one of the plurality of strings;

sensing the magnetic field caused by vibrations of particular ones of the plurality of strings, using the plurality of Hall effect sensors;

generating signals reflective of the sensed the magnetic field; and

encoding data reflective of music played using the stringed instrument by processing the signals.

20. A device for retrofitting a stringed instrument to encode music played using the instrument, the device comprising:

at least one magnet;

a plurality of Hall effect sensors;

a mount for mounting the device on the stringed instrument such that the at least one magnet provides a magnetic field proximate each of a plurality of strings of the stringed instrument, and such that each of the plurality of Hall effect sensors is disposed adjacent a string of the stringed instrument to generate a signal reflective of magnetic field changes caused by vibrations of that string; and

21 . A method of modifying a stringed instrument to encode music, the method comprising:

attaching at least one magnet to the stringed instrument, the at least one magnet adapted to provide a magnetic field proximate each of a plurality of strings of the stringed instrument; attaching a plurality of Hall effect sensors to the stringed instrument, each paired with one of the plurality of strings and configured to generate a signal reflective of changes in the magnetic field caused by vibrations of the paired string; and

providing a signal processor configured to process the signals generated by the plurality of Hall effect sensors to encode data reflective of music played on the stringed instrument.

22. A kit comprising:

a stringed instrument comprising a plurality of magnetically permeable strings; and

a device mountable to the stringed instrument, the device comprising:

at least one magnet for providing a magnetic field proximate each of the plurality of strings, when the device is mounted to the stringed instrument;

a plurality of Hall effect sensors, each for pairing with one of the plurality of strings and configured to generate a signal reflective of changes in the magnetic field caused by vibrations of the paired string, when the device is mounted to the stringed instrument; and

a signal processor configured to process the signals generated by the plurality of Hall effect sensors to encode data reflective of music played on the stringed instrument.

23. A stringed instrument comprising:

a plurality of magnetically permeable strings;

at least one magnet for providing a magnetic field proximate each of the plurality of strings;

24. A device for sensing music played using a stringed instrument, the device comprising:

a data transmission interface for transmitting the generated signals to an interconnected device.

25. A system for encoding music played using a stringed instrument, the system comprising:

a sensing device comprising:

at least one magnet for providing a magnetic field proximate each of a plurality of strings of the stringed instrument; and

a processing device connectable to the sensing device, the processing device comprising: