Abstract:
A string vibration pickup device and methods for using same. The device includes a sensor configured to engage a string to detect vibrations. A pickup base having a pickup in communication with the sensor receives electrical signals indicative of sensed vibrations for the string.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Application No. 61/928,921, filed Jan. 17, 2014, reference of which is hereby incorporated in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     String vibration pickup (SVP) system pertains to technology and designs for stringed instruments such as guitars that allows pitch detection—conversion of string&#39;s musical note information from transduced acoustic. Common approaches to solving the problem of automatic pitch detection from guitars, especially electric guitars, is to take the summed audio signal from all of the strings (6 for guitar, for example) and implement signal processing and/or machine learning algorithms to do pitch detection. In such environments—summed complex signals with as many pitches as strings—can be problematic as isolating and following individual pitch from a summed signal is nontrivial. However, if a string&#39;s vibration information is isolated, pitch detection becomes simpler. One of the most popular ways to isolate individual string pickup is through pickups placed on the bridge of a guitar (which is more difficult to install) or using hexaphonic magnetic pickups—pickups placed underneath the string, ideally picking up each string individually—that have one magnet per string. The hexaphonic magnetic approach has been widely used by pickup designers and guitar manufacturers. However, due to the proximity of the strings, a certain amount of crosstalk and bleeding occurs. 
     SUMMARY OF THE INVENTION 
     One implementation relates to a string vibration pickup device. The device includes a sensor configured to engage a string to detect vibrations and a pickup base having a pickup in communication with the sensor to receive electrical signals indicative of sensed vibrations for the string. 
     Another implementation relates to a string vibration pickup device comprising a sensor configured to engage a string to detect vibrations. The device further includes a pickup base having a pickup in communication with the sensor to receive electrical signals indicative of sensed vibrations for the string. A processor is configured to determine pitch from the electronic signals. 
     Another implementation relates to a method of detecting pitch of a device. A sensor is placed in contact with a string of the device. Vibrations of the string are detected with the sensor. The detected vibrations are converted into an electrical signal. The electrical signal is transmitted to a processor, which processes the electrical signal to determine the pitch of the string. 
     The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the following drawings and the detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing and other features of the present disclosure will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. Understanding that these drawings depict only several embodiments in accordance with the disclosure and are, therefore, not to be considered limiting of its scope, the disclosure will be described with additional specificity and detail through use of the accompanying drawings. 
         FIG. 1  is a side-view of a direct string vibration pickup layout. 
         FIGS. 2A-E  show a top down view of a number of different configuration and sensor placement. 
         FIG. 3  illustrates the place of sensors in relation to bridge in one embodiment. 
         FIGS. 4A and 4B  illustrate a magnetic clamping system alone above and with sensors. 
         FIG. 5  illustrates subtle adjustments of sensors with respect to strings. 
         FIG. 6  illustrates a sensor at rest and securely fastened. 
         FIG. 7  illustrates Sensor pulled up, slid, and released in small, discrete sliding increments 
         FIG. 8  illustrates Example of 6 string guitar outputting 6 channels of audio for each string. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In the following detailed description, reference is made to the accompanying drawings, which form a part hereof. In the drawings, similar symbols typically identify similar components, unless context dictates otherwise. The illustrative embodiments described in the detailed description, drawings, and claims are not meant to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented here. It will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the figures, can be arranged, substituted, combined, and designed in a wide variety of different configurations, all of which are explicitly contemplated and made part of this disclosure. 
     Described herein are systems and methods for direct string vibration pickup (DSVP) system  101  follows an approach that is contrary to standard practice of leaving the string untouched. One implementation utilizes a concept of physically contacting the string to convert the mechanical energy into electrical energy. The electrical energy is collected with minimal cross-talk or bleed associated with indirect string vibration pickup. Pitch detection algorithms can then be applied to each string individually to determine pitch. This design allows for individual string vibration measurement with minimal crosstalk. 
     One such implementation is show in  FIG. 1 . In a typical stringed instrument, a string  110 , which may be one of many, spans at least a distance between a first bridge  121  and a second bridge  122  or a head (not shown). A sensor  130  is positioned in contact with the string  110 . The sensor  130  is in electrical communication, such as via cable  131 , with the pickup base  140 . In one implementation, the sensor  130  is in communication with the pickup base  140  via a wireless connection such as WiFi or Bluetooth®. The sensor  130  comprises, in one implementation, a piezo film. In another implementation, the sensor  130  comprises a graphene film. 
       FIGS. 2A-E . below shows examples of different configurations for sensor  130  placement, though the invention is not limited to such configurations.  FIG. 2A  shows the sensor  130  that touches a string  110  from the side in perpendicular fashion.  FIG. 2B  shows the same configuration but from a different perspective—the string  110  going into the page.  FIG. 2C  shows a second configuration with the sensor  130  attached sideways and roughly centered on or below the string  110 .  FIG. 2D  shows the same configuration of  FIG. 2B , but again with the view of the string  110  going into the page.  FIG. 2E  shows the sensor  130  attached along the string  110 .  FIG. 2F  shows the same configuration of  FIG. 2E , but again with the view of the string  110  going into the page.  FIG. 2G  shows the sensor  130  leaning against the string  110  from the side.  FIG. 2H  shows the sensor  130  leaning against the string  110  from the top. 
     The configurations as shown in  FIG. 2A-H  allows individual sensors  130  to be attached to individual strings  110 , thereby allowing minimal to no crosstalk during the transduction process. In one implementation, the sensor  130  is placed near the bridge  121  of a guitar as shown in  FIG. 3 .  FIG. 3  illustrates implementation on a six-string guitar with each string  110  having an associated sensor  130  leaning against it side, similar to the configuration of  FIG. 2G . This setup helps in minimizing loss of mechanical energy due to friction between the sensor and string providing close to natural string vibration. The configuration can be changed to fit other stringed instruments, including but limited to 4-string bass guitars. 
     The tilted/leaning configuration of sensors  130  in  FIG. 3  have an important role as it allows the piezo film of the sensor  130  to make contact with the string  110  at all times due to the counteracting natural force of the film wanting to come to rest in its unbent, natural shape. To further help with robust contact and eliminate buzzing between the string  110  and sensor  130 , the sensor  130  may be magnetized. For example, the sensors  130  can be covered with a thin magnetic paste or the sensor  130  may be doped with a magnetic material. Various mechanisms may be utilized to attached the sensor  130  to the string  110 , including but not limited to removable mechanical attachment and adhesive (permanent and semi-permanent). In another implementation, the sensor  130  includes a clamp or two ridged placeholders to secure the sensor  130  to the string  110 . In this implementation, the string  110  fits between the two ridges or is held by a clamp. 
     An implementation of an enclosure  142  and pickup base  140  of the DSVP system is shown in  FIGS. 4A-4B . The pickup base  140  serves to receive the signal from the sensor  130 . A single pickup base  140  may be associated with a single sensor  130 . In an alternative implementation, a single pickup base  140  is associated with a plurality of sensors  130 , as shown, for example, in  FIG. 4B . In one implementation, the pickup base  140  is attachable, preferably removably attachable, to the instrument. For example, the base may be magnetic, such as comprising magnets in the pickup base  140 , which allow the DSVP system to be easily affixed onto standard electric guitar bridges. 
     The pickup base  140  may include an enclosure  142  to cover the internal components of the system  101 . In one implementation of the enclosure  142 , shown in  FIG. 4A , the enclosure  142  includes a first arm  143  and a second arm  144 . Each arm  143 ,  144  is L-Shaped and includes an adjustable connection mechanism to connect the first arm  143  and the second arm  144  such as by a securing screw  145 . The enclosure is affixed to the remainder of the pickup base  140  to help secure and position the pickup base  140 . In one implementation, the pickup base  140  stays secured on the bridge  121  of the guitar through magnetic force and the width can be adjusted to fit most guitars as the pickup base  140  is adjustable. The pickup base  140  can be further secured by using a securing screw that does not affect nor alter the guitar in any way. Note that the pickup base  140 , in one implementation, sits “on top” of the bridge and can, therefore, be shifted vertically. For implementations with instruments have a different configuration, the system  110  may also be attached below the strings  110  and in front of the bridge  121 . 
     In one implementation, best shown in  FIG. 5 , the pickup base comprises an adjustable width. In the implementation of  FIG. 5 , the pickup base  140  includes an adjustment of the total width and adjustment of the position of the pickup  138 . The pickup base  140  comprises a large base  148  that allows for an adjustment of rough width. For example, as shown in  FIG. 5 , a first portion  148   a  is nestable within a second portion  148   b  of the large base  148  to allow for adjustment of the width of the large base  148  by an amount Z. In one implementation, the large base  148  is adjustable along with the enclosure  144 . For example, as slidable large base  148  has a width that changes as the enclosure  144  is adjusted. This effectively allows the pickup base  140  to be sized for placement on various instruments, such as to accommodate instruments with a wide range of string spacing and number of strings. 
     In addition, the pickup  138  is mounted on a small base  145  that is adjustable relative to the large base  148 . The small base  145  may be mounted in a slidable manner, such as on a track  146 . The small base  145  is adjustable by an amount Y, allowing for fine adjustment to the position of individual string positions on an instrument. Each small base  145  may be adjusted its own amount as indicated by Y and X in  FIG. 5 . As also shown in  FIG. 5 , the pickup base may comprise a large base  148  and multiple small bases  145  each having a pickup  138  associated with a sensor  130  (not shown in  FIG. 5 ). To more finely position the sensors  130  with respect to the string  110 , adjustable screws  146  are provided in one implementation. A fastener  146  may be biased by a spring and secure the small base  145  to the large base  148  to allow for adjustment in two degrees. The fastener  146  may be a pin, bolt, screw, or the like. The pin  146  will secure the small base  145  against sliding and also provide some adjustment perpendicular to the plane along with the small base  145  slides. Further, as shown in  FIG. 6 , a ridge  150  and groove structure  149  on the small base  145  and large base  148  may help to secure the small base  145  with respect to the large base  148 . The groove structure  149  may be created by spaces between a series of raised portions  151 . 
     In one implementation, the small base  145  is adjustable with respect to the large base  148 . For example, as shown in  FIG. 7 , the large base  148  may have a slot (not shown) through which the fastener  146  may pass to secure the small base  145 . To reposition the small base  145 , the fastener  146  is removed, the small base  145  lifted from the large base  148 , slide or moved sideways then repositioned on the large base  148 . In one implementation such as shown in  FIG. 7  having the ridge  150  and groove  149  structure for securing the large base  148  and small base  145 , the fastener  146  may be loosened but not removed to allow the small base  145  to be sufficiently moved off of the large base such that the ridge  150  and groove  149  are no longer engaged, allowing the small base  145  to slide. In addition, certain embodiments may not use a fastener  146  but may include a snap-fit or friction fit between the small base  145  and the large base  148 . The materials used for the pickup bases  140  will include acoustic absorption materials to further minimize cross-talk between individual sensors  130 . That is, the small bases ( 145 ), large bases ( 148 ), and fastener  146  may include materials to reduce vibration and bleed. 
     The overall system is shown in  FIG. 8 , which consists of the pickup system  101  a single cable  109  from the pickup system  101  to an amplifier or audio interface [Not Shown]. In another implementation, the pickup system  101  may have an onboard signal processing unit and data is sent wirelessly via through standard wireless transmission technologies such as Bluetooth or WiFi. 
     The foregoing description of illustrative embodiments has been presented for purposes of illustration and of description. It is not intended to be exhaustive or limiting with respect to the precise form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired from practice of the disclosed embodiments. It is intended that the scope of the invention be defined by the claims appended hereto and their equivalents.