Conductive Fret Detection via Signal Inversion Frequency

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Solution Overview

Problem

Existing string instrument detecting systems face challenges in accurately determining the location of frets along the fretboard and identifying the musical notes played, particularly when multiple strings are pressed simultaneously, due to limitations in signal transmission and frequency detection.

Innovation Solution

A detecting system comprising conductive frets and strings with an inverter, frequency detector, and controller that logically inverts signals based on the distance between the inverter and the fret, allowing for precise measurement of frequency and determination of the fret location, enabling accurate detection of musical notes played on a string instrument.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional contact-based detection systems are used, then the structure is simple, but the ability to detect multiple simultaneous string presses accurately deteriorates

Engineering Contradiction:
Improvenote detection accuracyVSAvoiddetection system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces mechanical contact-based detection with electromagnetic induction. Conductive strings positioned near conductive frets create electrical signals through electromagnetic coupling when pressed, eliminating the need for direct mechanical contact sensors. This substitution enables accurate detection of multiple simultaneous presses without the complexity of multiple contact points.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces electromagnetic fields as an intermediary between the strings and frets. The conductive strings and frets act as indirect couplers, transmitting press information through electromagnetic induction rather than direct mechanical contact. This intermediary mechanism allows simultaneous detection of multiple string presses without signal interference.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If direct contact detection is used, then the device complexity is low, but the measurement precision of fret location deteriorates

Engineering Contradiction:
Improvefret location precisionVSAvoidsignal processing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces mechanical position sensing with electromagnetic field-based detection. The conductive strings and frets form an electromagnetic coupling system where the strength and characteristics of the induced signal provide precise information about fret location and string press position, achieving high measurement precision without complex mechanical position encoders.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If multiple strings are pressed simultaneously, then the musical expression capability is improved, but the reliability of note detection deteriorates due to signal interference

Engineering Contradiction:
Improvechord detection capabilityVSAvoiddetection reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent segments the detection system into independent conductive string-fret pairs, each forming its own electromagnetic coupling channel. This segmentation allows simultaneous detection of multiple string presses without cross-interference, as each pair operates independently through its own electromagnetic field, maintaining high reliability for chord detection.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The electromagnetic field serves as an intermediary that isolates each string-fret interaction. When multiple strings are pressed simultaneously, each generates its own electromagnetic signal through its respective conductive fret, preventing signal interference and enabling reliable detection of complex chords and simultaneous presses.

Inventive Principle:
Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The system effectively determines the location of frets and identifies musical notes by inverting signals and measuring frequencies, providing accurate note detection even when multiple strings are pressed, enhancing the precision and reliability of string instrument detection.

Implementation Method 1

an inverter having a first terminal coupled to the conductor and a second terminal coupled to the at least one conductive string and being configured to logically invert a signal transmitted therethrough such that when the at least one conductive string is pressed against one of the frets allowing thereby a signal to be transmitted therethrough

Methodology Applied
Scientific EffectElectrical signal transmission and inversion: Conduction (electrical)

Implementation Method 2

a frequency detector for measuring the frequency; and a controller for determining the location of the fret along the fretboard in accordance with the frequency

Methodology Applied
Scientific EffectFrequency measurement:

Data Source

PatentEP2959472B1Musical note detecting system for a string instrument
Publication Date: 2017.05.17 O M B GUITARS
  • EP2959472B1 patent drawingFigure 1~2
  • EP2959472B1 patent drawingFigure 3~4
  • EP2959472B1 patent drawing

AI summary

A detection system is provided for detecting a musical note played on a string instrument having a fretboard provided with a plurality of conductive frets and conductive strings. The system includes at least one conductor coupled to each of the frets; an inverter having a first terminal coupled to the conductor and a second terminal coupled to the conductive string, the inverter being configured to logically invert a signal transmitted therethrough, such that when the conductive string is pressed against one of the frets allowing thereby for a signal to be transmitted therethrough, the signal is sequentially inverted between two logical states at a frequency being dependent on the distance between the inverter and the fret; a frequency detector configured to measure the frequency; and a controller configured for determining the location of the fret along the fretboard in accordance with the frequency, and to thereby detect the musical note.