Passive Wireless Keyboard Using Piezoelectric Key Activation
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Solution Overview
Problem
Wireless keyboards face limitations due to battery replacement needs and inefficient power usage, leading to unreliable transmission and short battery life, which hinders their adoption over wired keyboards.
Innovation Solution
A passive wireless keyboard system using transponders and mechanical-to-electrical energy converters, such as piezo-electric or magnetic transducers, to modulate an interrogating field without battery power, enabling backscatter modulation and extended range and battery life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wireless keyboards use battery power for continuous key scanning and transmission, then transmission reliability is improved, but battery lifetime is limited and requires frequent replacement
Solution Approach 1:
The keyboard transitions from continuous scanning to periodic scanning, activating the transmitter only when a key is pressed. This periodic action maintains transmission reliability for data input while dramatically reducing power consumption, thereby extending battery lifetime.
Solution Approach 2:
The keyboard uses the energy from key press itself (mechanical energy) to power the transmission, making the system self-sufficient at the moment of data input without requiring continuous battery power for scanning.
2Ease of manufacture
If wireless keyboards use infrared transmission, then cost is reduced, but transmission consistency deteriorates when line of sight is blocked or keyboard is moved
Solution Approach 1:
The system dynamically adapts its transmission mode based on movement detection. When the keyboard is moved or orientation changes, the system adjusts to maintain RF connection, providing transmission consistency comparable to wired keyboards while maintaining cost-effectiveness.
3Reliability
If wireless keyboards use RF transmission with higher power, then transmission range and reliability are improved, but power consumption increases and battery lifetime decreases
Solution Approach 1:
The high-power RF transmitter is activated only periodically when keys are pressed rather than continuously, maintaining transmission reliability for data communication while minimizing overall power consumption and extending battery lifetime.
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 reliable and efficient short-range wireless transmission without battery power, reducing clutter and improving user experience by eliminating the need for frequent battery replacements and enhancing keyboard functionality.
Implementation Method 1
one or more mechanical to electrical energy converters responsive to key activation and providing power to the one or more transponders
Implementation Method 2
one or more antennas coupled to the one or more transponders and modulating the interrogating field with a coded signal in response to key activation
Data Source
AI summary
A wireless controller, such as a keyboard, and reader combination comprises a controller having a plurality of keys, one or mechanical to electrical energy converters providing energy from key activation, an antenna, and one or more passive transponder circuits, coupled to the antenna and associated with the keys. The passive transponder circuits provide a coded response identifying a key in response to key activation employing power from the key activation to modulate the interrogating field. In particular backscatter modulation using the reflected interrogating field may be employed. An associated reader includes a source of the interrogating field applied to the antenna of the keyboard and a decoder for determining the coded response from the passive transponder circuits.