Piezo Transducer Tap Pattern Recognition for Infusion Pump Control
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Solution Overview
Problem
Infusion pumps often become disconnected from external controllers, necessitating a manual control option and alarm generation capability to ensure timely insulin delivery and alert users to pumping status without unnecessary battery drain from unintentional activations.
Innovation Solution
A piezo transducer-based system with a pressure pattern recognition circuit that detects specific tap patterns to manually control the pump and generate alarms, using a comparator, oscillator, and tri-state buffer to switch between sensor and alarm modes, ensuring accurate and intentional activation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a piezo transducer is used as a touch sensor for manual control, then ease of operation is improved, but reliability deteriorates due to unintentional activations from pressure changes during normal use
Solution Approach 1:
The system requires a specific periodic pattern of taps (e.g., two or more rapid successive taps within a defined time window) to activate manual control mode. This periodic action requirement ensures that normal pressure changes during use do not trigger false activations, while still allowing intentional user input when needed.
Solution Approach 2:
The system incorporates feedback mechanisms where the microcontroller monitors the piezo transducer output and analyzes the temporal pattern of pressure events. By comparing the detected pattern against predefined activation criteria, the system provides feedback control that distinguishes between intentional user input and unintentional pressure changes.
2Speed
If the piezo transducer is continuously monitored for pressure changes, then responsiveness is improved, but energy consumption increases
Solution Approach 1:
Instead of continuous monitoring, the system uses periodic sampling of the piezo transducer signal at predetermined intervals. This approach maintains adequate responsiveness to user input while significantly reducing the energy consumption associated with continuous signal processing and microcontroller operation.
Solution Approach 2:
The piezo transducer circuit is designed to self-activate the microcontroller only when a valid pressure pattern is detected. The system remains in a low-power state until the transducer generates a signal meeting the activation criteria, at which point the microcontroller automatically wakes up to process the input, eliminating the need for continuous power consumption.
3Device complexity
If the piezo transducer is used for both touch sensing and alarm generation, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The system dynamically reconfigures the piezo transducer's functional role based on operational context. A switch or tri-state buffer enables the transducer to operate in different modes: as a touch sensor for manual control, as an alarm output device, or in a high-precision measurement mode. This dynamic switching allows the same hardware component to serve multiple functions while maintaining measurement precision when needed.
Solution Approach 2:
The piezo transducer is designed as a universal component capable of performing multiple functions: detecting pressure patterns for manual control activation, generating audible alarm signals, and providing pressure measurements. The system software or control logic selectively activates the appropriate function based on the current operational state, reducing overall device complexity while maintaining functional precision.
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 users to manually control insulin delivery and receive timely alerts without battery drain from unintentional activations, providing a reliable and user-friendly interface for infusion pumps.
Implementation Method 1
a piezo transducer for detecting a pressure pattern applied to the sensor
Implementation Method 2
an oscillator provides an oscillating signal, thereby increasing a drive voltage to the transducer
Data Source
AI summary
Devices and methods are provided for selectively driving a piezo transducer to operate as a pressure pattern detector or an alarm generator. In one embodiment, there is provided a device that includes: a piezo transducer; a comparator coupled to the transducer and a reference voltage; and a pressure pattern recognition circuit coupled to a comparator output of the comparator. The pressure pattern recognition circuit may be configured to: (i) determine whether the pressure pattern satisfies a predetermined condition; and (ii) in response to the pressure pattern satisfying the predetermined condition, generate an output signal.