Claims
- 1. A magnetic sensor for a musical instrument having vibrating magnetic elements to produce musical notes, which magnetic sensor is suitable for attachment to the frame of the instrument and which magnetic sensor produces an electronic signal in response to the vibration of any of the vibrating magnetic elements, comprising;
- a flexible, electrostatically shielded, coil-magnet comprising:
- a flexible bar magnet of predetermined length, width and thickness, the bar magnet having two major surfaces defined by the length and width of the bar magnet and having side surfaces, wherein the poles of the magnet are the major surfaces and wherein a uniform magnetic flux density exists across the thickness of the bar between the poles of the bar magnet;
- a coil comprising a predetermined number of windings of a conductor which are wound around the side surfaces of the bar magnet; and
- electrostatic shielding material which is adhesively bound to the major surfaces of said bar magnet and which encompasses and encloses said bar magnet and windings;
- a two-wire cable connected to the ends of the coil of said coil-magnet; and
- flexible, non-conductive material encompassing said coil-magnet and the connection of the two-wire cable to the coil of the coil-magnet.
- 2. The magnetic sensor of claim 1, wherein it additionally comprises a magnetic spacer for insertion between the magnetic sensor and the frame of the musical instrument to bring the magnetic sensor into proximity to the vibrating strings of the instrument.
- 3. The magnetic sensor of claim 2, wherein the magnetic spacer comprises:
- a flexible bar magnet having a predetermined length, width, and thickness; and
- flexible, non-conductive material applied to the bar magnet.
- 4. The magnetic sensor of claim 3, wherein the flexible, non-conductive material applied to the bar magnet is heat shrinkable tubing.
- 5. The magnetic sensor of claim 4, wherein the electrostatic shielding material is aluminum foil.
- 6. The magnetic sensor of claim 4, wherein the two-wire cable is a coaxial cable.
- 7. A magnetic sensor for an instrument having vibrating magnetic elements to produce musical notes and a magnetic frame, which magnetic sensor is suitable for attachment to the frame of the instrument and which magnetic sensor produces an electrical signal in response to the vibration of the vibrating magnet material, comprising:
- a flexible bar magnet of predetermined length, width, and thickness, the bar magnet having two major surfaces defined by the length and width of the bar magnet and having side surfaces, wherein the poles of the magnet are the major surfaces and wherein a uniform magnetic flux density exists across the thickness of the bar between the poles of the bar magnet;
- a coil comprising a predetermined number of windings of a conductor wound around the side surfaces of the bar magnet;
- electrostatic shielding material encompassing and enclosing said bar magnet and windings;
- a two-wire cable with one conductor thereof attached to one side of the coil of the coil magnet and with the other conductor thereof attached to the other side of the coil of the coil magnet; and
- flexible, non-conductive material encompassing the electrostatically shielded bar magnet with windings and the connection of the two-wire cable to the conductors of the coil magnet.
- 8. A method of constructing a magnetic sensor for an instrument having vibrating magnetic elements to produce musical notes, which comprises:
- selecting a flexible bar magnet of predetermined length, width and thickness, the bar magnet having two major surfaces defined by the length and width of the bar magnet and having two side surfaces, wherein the poles of the selected bar magnet are the major surfaces and the bar magnet having a uniform magnetic flux density across the thickness of the magnet between the poles of the magnet;
- adhesively bonding sheets of electrostatic shielding material to the poles of the bar magnet;
- constructing the coil of the coil magnet by winding a predetermined number of turns of a conductor around the side surfaces of the magnet, the turns of said coil encircling the bar magnet;
- folding the sheets of electrostatic shielding material around the bar magnet and the coil to electrostatically shield the bar magnet and coil;
- connecting the conductors of a two-wire cable to the ends of the coil of the coil-magnet; and
- applying a flexible, non-conductive material to the flexible, electrostatically shielded coil-magnet.
- 9. The method of claim 8, wherein the electrostatic shielding material is aluminum foil.
- 10. The method of claim 8, wherein the flexible non-conductive material is heat shrinkable tubing and thereafter applying heat to shrink the tubing.
- 11. The method of claim 8, wherein the two-wire cable is a coaxial cable.
- 12. A method of constructing a magnetic sensor for an instrument having vibrating elements to produce musical notes, which comprises:
- selecting a vinyl bar magnet of predetermined length, width and thickness, the vinyl bar magnet having two major surfaces defined by the length and width of the bar magnet, wherein the poles of the magnet are the major surfaces and wherein a uniform magnetic flux density exists between the poles of the bar magnet;
- adhesively bonding sheets of aluminum foil to the poles of the bar magnet;
- constructing the coil of the coil-magnet by winding a predetermined number of turns of a conductor around the side surfaces of the magnet, the turns of said coil encircling the bar magnet;
- folding the sheets of the aluminum foil around the bar magnet and coil to electrostatically shield the bar magnet and coil;
- attaching a connector to the bar magnet;
- selecting a coaxial cable of predetermined length;
- connecting one end of the coil and the shield at a first end of the coaxial cable to the connector;
- connecting the second end of the coil to the center connector of the coaxial cable at the first end of the coaxial cable;
- encompassing the electrostatically shielded coil-magnet and the connector with heat shrinkable tubing;
- applying heat to the heat shrinkable tubing to cause it to conform to the shape of the coil-magnet; and
- connecting a connector to the second end of the coaxial cable.
- 13. The method of claim 12, wherein the coil comprises 300 turns of the conductor.
- 14. A method of adapting an upright piano for electric amplification, the upright piano having a plurality of string sections, a frame and a space between each string section and the frame utilizing a flexible magnetic sensor which flexible magnetic sensor comprises:
- (a) a flexible, electrostatically shielded coil magnet;
- (b) a two-wire cable connected to the ends of the coil of the coil magnet; and
- (c) flexible, nonconductive material encompassing the coil magnet and the connection of the two-wire cable to the coil of the coil magnet;
- the method comprising the steps of:
- (1) inserting a flexible magnetic sensor into the space between one string section and the frame of the piano, the magnetic sensor being of a length greater than or equal to the width of that string section and the magnetic sensor having two major surfaces which are magnetic;
- (2) attaching one major surface of the magnetic sensor to the frame of the upright piano; and
- (3) repeating steps (1) and (2) for each string section of the piano.
- 15. A method of adapting an upright piano for electric amplification, the upright piano having a plurality of string sections, a frame and a space between each string section and the frame wherein the method utilizes a flexible magnetic sensor which comprises:
- (a) a flexible bar magnet having a length greater than or equal to the width of the string section behind which the magnetic sensor is inserted and having a predetermined width and thickness, the bar magnet having two major surfaces defined by the length and width of the bar magnet and having side surfaces, wherein the poles of the magnet are the major surfaces and wherein a uniform magnetic flux density exists across the thickness of the bar between the poles of the bar magnet;
- (b) a coil comprising a predetermined number of windings of a conductor wound around the side surfaces of the bar magnet;
- (c) electrostatically shielding material encompassing and enclosing said bar magnet and windings;
- (d) a two-wire cable with one conductor thereof attached to one side of the coil of the coil magnet and with the other conductor thereof attached to the other side of the coil of the coil magnet; and
- (e) flexible, nonconductive material encompassing the electrostatically shielded bar magnet with windings and the connection of the two-wire cable to the conductors of the coil magnet;
- the method comprising the steps of:
- (1) inserting a flexible magnetic sensor into the space between one string section and the frame of the piano, the magnetic sensor being of a length greater than or equal to the width of that string section and the magnetic sensor having two major surfaces which are magnetic;
- (2) attaching one major surface of the magnetic sensor to the frame of the upright piano; and
- (3) repeating steps (1) and (2) for each string section of the piano.
Parent Case Info
This application is a continuation application of previously filed Ser. No. 621,365, filed on Oct. 10, 1975, and which application has been abandoned.
US Referenced Citations (5)
Continuations (1)
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Number |
Date |
Country |
Parent |
621365 |
Oct 1975 |
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