Capacitive Touch Sensor Shielding for Percussion Instruments
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Solution Overview
Problem
Existing electronic musical instruments and interactive games, toys, and books require expensive components and complex manufacturing techniques, limiting their affordability and functionality, particularly in simulating percussion instruments effectively.
Innovation Solution
The development of an electronic percussion instrument using thin film capacitive touch sensors integrated with an art layer, a shielding layer, and an electronics package, which allows for inexpensive and flexible construction with one-sided triggering, reducing the risk of false triggers and enabling integration of artwork with sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If thin film capacitive touch sensors are used, then manufacturing cost and flexibility are improved, but false triggers from two-sided sensitivity worsen reliability
Solution Approach 1:
A shielding layer is introduced as an intermediary element between the sensor and the environment. This shielding layer blocks capacitive coupling from objects approaching from the backside, preventing false triggers while preserving the thin film sensor's cost-effectiveness and flexibility.
Solution Approach 2:
The problem of two-sided sensitivity is solved by adding a spatial dimension - a shielding layer positioned on the backside of the sensor. This creates an asymmetric structure where the front side remains sensitive to touch while the back side is blocked, converting the two-sided sensor into a functionally one-sided sensor.
2Measurement precision
If traditional capacitive touch sensors are used, then sensitivity is improved, but device thickness and complexity worsen
Solution Approach 1:
The patent uses thin film capacitive touch sensors deposited on flexible substrates, replacing traditional thick rigid sensor structures. This maintains touch sensitivity while dramatically reducing thickness and structural complexity, enabling integration into flexible electronic musical instruments.
3Reliability
If one-sided triggering is implemented, then false triggers are reduced, but sensor responsiveness to legitimate touches may be limited
Solution Approach 1:
The sensor system implements different properties on different sides: the front side maintains high capacitive sensitivity for legitimate touch detection, while the back side is blocked by a shielding layer to prevent false triggers. This local differentiation of properties solves the contradiction between reliability and responsiveness.
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 solution provides an affordable, flexible, and functional electronic percussion instrument with improved sensitivity and reduced complexity, enabling realistic simulation of percussion instruments while minimizing costs and manufacturing challenges.
Implementation Method 1
A capacitive touch sensor typically is a small capacitor enclosed in an electrical insulator. The capacitor has an ability to store an electrical charge, referred to as capacitance. When a power source applies an increased voltage across the capacitor, electrical charges flow into the capacitor until the capacitor is charged to the increased voltage. Similarly, when the power source applies a decreased voltage the capacitor, electrical charges flow out of the capacitor until the capacitor is discharged to the decreased voltage. The amount of time it takes for the capacitor to charge or discharge is dependent on the change in voltage applied and the capacitance of the capacitor. If the capacitance is unknown, it can be calculated from the charge or discharge time and the change in voltage applied. A person touching or coming close to a capacitive touch sensor can change the sensor's effective capacitance by combining the person's capacitance with the capacitance of the capacitive touch sensor. This change in effective capacitance can be detected by a change in the charge or discharge times.
Data Source
AI summary
An electronic instrument simulating a percussion instrument using capacitive touch sensitive sensors. The instrument has an art layer, a sensor layer, a shielding layer, an electronics package and a speaker. The art layer has depictions of one or more percussion instruments. The sensor layer is deposed under the art layer. The sensor layer has one or more instrument sensors, each with one or more capacitive touch sensors. Instrument sensors are positioned underneath one of the depicted percussion instruments in the art layer so that a finger tapping the depicted instrument will trigger the sensor. The capacitive touch sensors are electrically connected to the electronics package configured to detect changes in capacitance when a particular capacitive touch sensor is touched, causing the electronics package to play on the speaker a sound sample of an percussion instrument associated with that capacitive touch sensor.