RFID Tag Audio Playback via PWM Parameter Extraction
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Solution Overview
Problem
Current RFID systems lack the capability to efficiently play back audio messages using RFID tags, particularly due to the absence of integrated micro-controllers and high costs associated with existing audio playback solutions.
Innovation Solution
The implementation of an RFID tag with a configuration and control circuit, a memory module, and a PWM circuit that can automatically read and generate PWM signals from stored parameters, enabling audio playback without the need for a micro-controller, and potentially powered by an energy harvest circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an RFID tag integrates a micro-controller to enable audio playback, then audio playback capability is achieved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent extracts the micro-controller from the RFID tag system and relocates it to the reader device. The RFID tag is reduced to basic components (RFID block, memory, PWM circuit, and state machine), while the reader assumes the role of audio data processor and transmitter. This extraction resolves the contradiction by eliminating the need for a micro-controller in the tag, thereby reducing device complexity and cost while preserving audio playback capability through the reader's processing power.
Solution Approach 2:
The patent introduces a state machine as an intermediary between the memory and PWM circuit within the RFID tag. This simple state machine coordinates the sequential reading of PWM parameters from memory and their transmission to the PWM circuit, enabling audio playback functionality without requiring a complex micro-controller. The intermediary state machine resolves the contradiction by providing minimal control logic necessary for audio playback while keeping device complexity low.
2Measurement precision
If an RFID tag uses traditional audio playback components, then audio quality is improved, but manufacturing cost increases
Solution Approach 1:
The patent replaces traditional mechanical audio playback components (such as DACs, amplifiers, and speakers) with an electromagnetic field-based PWM transmission system. The RFID tag stores audio as PWM parameters in memory and transmits them via electromagnetic coupling to the reader, which reconstructs the audio signal. This substitution eliminates expensive audio hardware from the tag while maintaining audio quality through digital PWM parameter transmission, thereby resolving the contradiction between audio quality and manufacturing cost.
Solution Approach 2:
The patent changes the representation and transmission parameters of audio data from traditional analog waveforms to digital PWM parameters. By storing and transmitting audio as a sequence of PWM parameters (frequency, duty cycle, duration) rather than continuous analog signals, the system achieves high-quality audio reproduction through simple digital components. This parameter transformation resolves the contradiction by enabling quality audio playback using low-cost digital memory and transmission components instead of expensive analog audio hardware.
3Ease of operation
If an RFID tag operates without external power sources, then portability and ease of use are improved, but energy availability for audio playback is limited
Solution Approach 1:
The patent implements self-service by enabling the RFID tag to harvest energy from the electromagnetic field generated by the reader during communication. The tag uses this harvested energy to power its memory operations and PWM parameter transmission for audio playback. This eliminates the need for external power sources or batteries, maintaining portability while providing sufficient energy for audio playback through the self-powered electromagnetic coupling mechanism between reader and tag.
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
This solution allows for cost-effective, high-quality digital audio playback on RFID tags, reducing system costs and eliminating the need for external power sources, while enabling efficient transfer and playback of audio messages.
Implementation Method 1
RFID is used to uniquely identifying items using radio waves. The RFID reader sends an interrogating signal (e.g., a radio-frequency signal) to the RFID tag, and the RFID tag responds with its unique information.
Implementation Method 2
a PWM circuit configured to generate a PWM signal based on a PWM parameter received by the PWM circuit
Data Source
AI summary
A radio-frequency identification (RFID) device includes an RFID block configured to support RFID communication; a memory having a storage area configured to store a list of pulse width modulation (PWM) parameters; a PWM circuit configured to generate a PWM signal based on a PWM parameter received by the PWM circuit; and a configuration and control (CC) circuit coupled to the RFID block, the memory, and the PWM circuit, where the RFID block, the PWM circuit, the CC circuit, and the memory form part of an RFID tag, where the CC circuit is configured to, in an automatic playback mode: sequentially read the list of PWM parameters from a beginning of the list of PWM parameters; and sequentially send the list of PWM parameters to the PWM circuit.