Acoustic Touch Typing Emulator Using Dual Sensor Wave Dispersion
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Solution Overview
Problem
Existing virtual input devices for computers, such as miniature keyboards and touch screens, face challenges in accurately detecting finger positions on surfaces without a complex combination of multiple sensors, failing to provide a simple setup for virtualizing keyboard input.
Innovation Solution
A touch typing emulator using as few as two acoustic sensors connected by a wire, which detect different acoustic waves (surface and airborne waves or wave modes with different velocities) to calculate the location and time of finger contact on a flat surface, emulating a typewriter keyboard.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple sensors are used to detect finger position accurately, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The acoustic wave detection is segmented into multiple wave modes (surface waves and airborne waves) that travel at different velocities. Each wave mode provides independent timing information, allowing the system to calculate finger position accurately using only two sensors rather than requiring a complex array of multiple sensors.
Solution Approach 2:
The patent replaces a complex mechanical sensor array with a simpler acoustic wave-based detection system. By using acoustic waves that propagate through the surface and air, the system achieves accurate finger position detection without requiring multiple physical sensors in close proximity, thereby reducing device complexity.
2Ease of manufacture
If acoustic sensors are used to detect finger taps, then ease of manufacture is improved, but measurement precision deteriorates due to inability to determine which finger struck the surface
Solution Approach 1:
The patent adds the time dimension to the detection by measuring the arrival times of different acoustic wave modes. Since surface waves and airborne waves travel at different velocities, they arrive at sensors at different times, creating a temporal signature that allows the system to distinguish between fingers even with only two sensors.
Solution Approach 2:
The system changes the detection parameter from spatial arrangement of multiple sensors to temporal analysis of wave arrival times. By measuring when different wave modes arrive at the sensors rather than relying on sensor position, the system achieves finger identification accuracy while maintaining ease of manufacture.
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 effective alphanumeric input on any flat surface, including miniaturized devices like smartphones and tablets, by determining the location and timing of finger strikes with high accuracy, reducing the need for complex sensor setups and providing a virtual keyboard interface.
Implementation Method 1
Some have employed light scanners to form a real-time image of the position of the user's fingers and relied upon an acoustic signal to detect that the hand has tapped a surface
Implementation Method 2
detecting either different acoustic waves, such as a surface wave and an airborne wave, two different modes of wave motion, such as longitudinal and transverse propagated waves
Implementation Method 3
different portions of a single wave separated by dispersion. In each case, the two waves propagate with different velocities
Implementation Method 4
Others have used rows of acoustic sensors to replace rows of keys on a typewriter input
Data Source
AI summary
A touch typing emulator to be placed on any flat surface is made from as few as two acoustic sensors connected by a wire that determines the separation between the sensors and is connected by a USB cable to a computer. The emulator receives two waves from each finger tap on the surface, a higher velocity wave and a lesser velocity wave. By affixing the sensors to a surface, the sensors, in connection with software in a computer receiving the USB connection, determines the location of the tapping of a users fingers on the surface and uses that information to emulate a typewriter keyboard.