Touchless Keypad Distance Sensing for Accurate Key Selection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing contactless input entry systems provide limited feedback to users, often relying on binary responses and sensors with low resolution, which cannot distinguish between fingers and hands, leading to increased key separation requirements, limiting their applicability to small devices like ATMs and credit card readers.
Innovation Solution
A touchless input device with a plurality of time of flight sensors that measure linear distance and rate of approach, providing continuous feedback through visual and audible indicators, allowing key regions to be placed closer together and accurately distinguishing between finger and hand-sized objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensors with limited resolution are used to detect object approach, then the system can detect object presence, but the system cannot distinguish between finger and hand-sized objects, leading to false positives
Solution Approach 1:
The patent transitions from binary detection (presence/absence) to multi-dimensional measurement by incorporating linear distance measurement capability. The sensor measures not only whether an object is present but also how far away it is, creating a distance dimension that enables differentiation between finger-sized and hand-sized objects based on their characteristic approach distances to key regions.
Solution Approach 2:
The system changes the detection parameter from simple presence detection to continuous linear distance measurement. By measuring the distance parameter continuously as an object approaches, the system can identify characteristic distance profiles for different object types (finger vs. hand), thereby improving both measurement precision and reliability.
2Area of stationary object
If key regions are placed closer together to reduce device size, then the device becomes more compact and adaptable, but the risk of false key selection increases due to limited sensor resolution
Solution Approach 1:
The patent adds a distance dimension to key selection detection. Instead of relying solely on lateral position detection with limited resolution, the system measures the distance from the sensor to the approaching object. This distance information creates an additional dimension for discrimination, allowing compact key layouts while maintaining selection accuracy through triangulation-like logic.
Solution Approach 2:
The patent replaces the mechanical constraint of fixed key spacing (determined by sensor resolution limits) with an optical/mathematical solution using distance measurement. The system substitutes physical separation requirements with computational discrimination based on distance vectors, enabling denser key arrangements without sacrificing reliability.
3Device complexity
If binary feedback is provided to users, then the system is simple to implement, but the user has no way of knowing they are about to select a key until after selection occurs
Solution Approach 1:
The patent implements continuous feedback based on the measured linear distance. As the object approaches the key region, the system provides progressive feedback indicating the approaching object's distance and likely target key. This feedback loop occurs before selection, allowing the user to awareness and correct their action if needed, transforming the interaction from post-selection notification to pre-selection guidance.
Solution Approach 2:
The system performs preliminary detection and notification actions before the actual key selection occurs. By measuring distance continuously and providing feedback during the approach phase, the system prepares the user in advance of the selection moment, enabling corrective action if the wrong key is being approached.
4Object-affected harmful factors
If contactless input systems are implemented, then hygiene is improved by reducing surface contact, but the system requires larger key separation to compensate for limited sensor resolution
Solution Approach 1:
The patent replaces the mechanical requirement for large key spacing (needed for low-resolution contactless sensors) with an optical/mathematical approach using linear distance measurement. The distance vector information provides additional discriminative power that substitutes for physical separation, allowing contactless operation with compact key layouts.
Solution Approach 2:
The system adds the distance dimension to contactless detection, enabling compact keypad designs. The extra dimensional information from distance measurement compensates for the lack of physical key separation, maintaining both hygiene benefits and space efficiency.
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 precise selection of key regions with reduced key separation, enhancing user interaction and adaptability to various devices, including small keypads, while providing clear and continuous feedback.
Implementation Method 1
a time of flight sensor arranged behind the button and configured to determine a linear distance of an object coming into proximity with the input device
Data Source
AI summary
An input assembly comprises a plurality of visual indicators differentiating between key regions on a plane. The input assembly also comprises a plurality of sensors, each arranged behind one of the key regions, and configured to determine a linear distance of the object from each of the sensors when the object is coming into proximity with the plane. Processing circuitry is configured to, based on input from the sensors, determine a location of a selected key region that the object is approaching; instruct changing of a display of at least one of the plurality of visual indicators to highlight the selected key region with a first visual indication when an object approaches within the first predefined proximity of the selected key region; select, from among a plurality of values, a value that is associated with the selected key region, and output the selected value as a user-selected keypad value.