Tone-Based Wake-Up Circuit for Card Readers
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Solution Overview
Problem
Conventional point-of-sale systems with card readers often consume battery power when idle and require complex or bulky equipment, making them inefficient and inconvenient, especially when trying to turn them back on without disconnecting from a mobile device.
Innovation Solution
A tone-based wake-up circuit that uses an audio signal from a mobile device to power on a card reader without draining its battery, utilizing a conditioning circuit, comparator, and envelope detector to convert the audio signal into a DC voltage, allowing the card reader to turn on and off as needed without battery consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the card reader is left plugged into a mobile device after being powered down by the microcontroller, then the device remains connected and available, but the card reader cannot be turned back on without disconnecting and reconnecting because the microphone bias signal does not change
Solution Approach 1:
The patent replaces the mechanical/manual disconnection-reconnection process with an acoustic signal-based wake-up mechanism. The envelope detector circuit monitors the audio jack for specific acoustic patterns (such as a clap or voice command) and triggers the microcontroller to power on the card reader, eliminating the need for physical disconnection while using a simple, low-power monitoring approach.
Solution Approach 2:
The patent introduces an acoustic signal as an intermediary trigger mechanism. Instead of directly monitoring power signals or requiring physical connection changes, the system uses sound waves detected by the audio jack as a mediator to initiate the power-on sequence, providing a convenient and intuitive user interaction method.
2Extent of automation
If conventional monitoring circuits are used to detect card insertion and trigger power on, then the card reader can turn on automatically, but the internal battery is drained continuously
Solution Approach 1:
The patent implements periodic or event-driven monitoring instead of continuous monitoring. The envelope detector circuit remains in a low-power state and only becomes active when it detects specific acoustic patterns in the audio jack, such as a clap sound or voice command. This periodic activation based on external triggers significantly reduces battery consumption compared to continuous monitoring while still providing automatic detection capability.
3Reliability
If the card reader requires disconnection and reconnection to turn on, then the system ensures complete power cycle, but the user experience becomes inconvenient and time-consuming
Solution Approach 1:
The patent performs preliminary setup by keeping the audio jack monitoring circuit ready and connected at all times in a low-power state. The envelope detector is pre-configured to recognize wake-up triggers, so when the user makes a sound (clap, voice command), the system can immediately initiate the power-on sequence without requiring physical disconnection and reconnection, thus maintaining reliability while reducing the time required.
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 the card reader to efficiently turn on and off using a tone signal, reducing battery drain and eliminating the need for manual disconnection, while ensuring the system remains functional for immediate use without complex monitoring circuits.
Implementation Method 1
an envelope detector connected to an output of the comparator, the envelope detector configured to convert the output signal to a DC voltage signal
Data Source
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AI summary
A card reader for a point-of-sale system that is configured to accept both magnetic strip-type and integrated circuit (IC) chip-type payment cards. The card reader is a component of a point-of-sale system including a portable computing device in communication with the card reader that is configured to present a first graphical user interface (GUI) when a magnetic stripe-type card is detected and a second GUI when an IC chip-type card is detected in the card reader. The card reader comprises a slot configured to receive the payment card, a magnetic reading device and an IC chip reading device. The card reader also includes a discriminator contact disposed within the slot that is configured to conduct across a surface of a metal pad of the IC chip-type card prior to the CI chip reading device making contact with the IC chip.