Single-Conductor Capacitive Touch Sensor for 3D Printed Objects
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Solution Overview
Problem
Current touch sensors are not suitable for integration into complex 3D objects, limiting interactivity in 3D printed items which are typically static and lack interactive capabilities.
Innovation Solution
A single-conductor capacitive touch sensor system that uses a computational pipeline to create unique RC time delays for each touchpoint, enabling capacitive sensing in 3D models with minimal electronic components and wiring, allowing for interactivity in 3D printed objects across various geometries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional touch sensors are integrated into complex 3D objects, then interactivity is improved, but device complexity and instrumentation requirements increase significantly
Solution Approach 1:
The patent combines multiple sensing functions into a single conductor system. The resistor network and capacitive sensing are merged into one integrated structure where a single conductor serves both as the sensing element and the signal pathway, eliminating the need for separate sensor components at each touchpoint.
Solution Approach 2:
The single conductor system performs multiple functions: it serves as the sensing element, the signal transmission medium, and the reference potential. This universal approach allows the same conductor to enable capacitive touch sensing across multiple touchpoints without requiring dedicated sensors for each location.
2Device complexity
If multiple touchpoints are sensed using a single channel, then device complexity is reduced, but measurement precision may be compromised
Solution Approach 1:
The resistor network is segmented into multiple sections, each section corresponding to a specific touchpoint. By measuring the RC time constant at different segments of the resistor network, the system can precisely identify which touchpoint is being activated while using only a single conductor and microcontroller channel.
Solution Approach 2:
The patent uses RC time constants as unique parameters for each touchpoint. By varying the resistance values in different segments of the resistor network, each touchpoint produces a distinct time constant that the microcontroller can measure and use to identify the specific touch location with high precision.
3Measurement precision
If RC delay sensing is implemented across multiple touchpoints, then measurement precision is improved, but device complexity increases due to resistor network requirements
Solution Approach 1:
The resistor network is merged with the conductor structure itself. Rather than being separate discrete components, the resistive elements are integrated into the conductor path, creating a unified structure that provides both mechanical support and electrical sensing functionality.
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
Enables interactive functionality in 3D printed objects by uniquely identifying touchpoints through capacitive sensing, providing a scalable, accurate, and applicable solution for a wide range of 3D geometries with minimal instrumentation.
Implementation Method 1
RC delay is the time required to charge a capacitor in a circuit through a particular amount of resistance. By creating unique RC time delays for all touchpoints, each touchpoint can be capacitively sensed using a single-wire or double-wire connection.
Implementation Method 2
RC delay is the time required to charge a capacitor in a circuit through a particular amount of resistance.
Implementation Method 3
detect a voltage drop on the first subcircuit responsive to one of the plurality of touch-sensing nodes being touched or contacted... determine which of the plurality of touch-sensing nodes was touched or contacted (e.g., by a capacitive body, human or otherwise)
Data Source
AI summary
An exemplary system and method for a single-conductor capacitive touch or contact sensor or human-machine-interface that can be integrated into a 2D or 3D-formed body. The exemplary system and method can be employed in the design and/or construction/fabrication of a tactile sensor-device having minimal instrumentation and wiring to provide interactive functionality. In some embodiments, the exemplary system and method can provide n number of sensing nodes on a device through the use of a single channel input of a controller without multiplexing by evaluating and encoding each sensing node to an RC delay uniquely established for the sensing node.