Hall-Effect Sensor Automatic Thermometer Activation
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Solution Overview
Problem
Conventional automatic on/off mechanisms in electronic thermometers, such as mechanical switches and optical switches, are prone to wear, complex, costly, and inefficient in terms of battery power consumption, and can be affected by debris and humidity.
Innovation Solution
A solid-state activating system using a Hall-effect sensor and a magnet to automatically switch the thermometer between active and non-active states, eliminating the need for manual operation and reducing power consumption by utilizing a low-power, omnipolar Hall-effect sensor with a digital output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If a mechanical switch is used for automatic on/off mechanism, then the thermometer can be automatically powered on/off, but the switch is prone to wear and failure due to moving mechanical parts
Solution Approach 1:
The patent replaces the mechanical switch with an optical switch that uses light detection instead of moving parts. The optical switch includes a light source and light detector that detect the presence or absence of the probe through light transmission, eliminating mechanical wear and improving reliability while maintaining automatic on/off functionality.
2Extent of automation
If an optical switch is used for automatic on/off mechanism, then the thermometer can be automatically powered on/off, but the system consumes substantial battery power
Solution Approach 1:
The patent implements periodic polling of the light detector at low power modes instead of continuous operation. The microcontroller periodically checks the light detector state to determine probe presence, allowing the optical switch components to remain in low-power states between checks, thereby significantly reducing battery consumption while maintaining automatic on/off capability.
3Extent of automation
If an optical switch is used for automatic on/off mechanism, then the thermometer can be automatically powered on/off, but debris in the probe well may block the light beam and interfere with detection
Solution Approach 1:
The patent positions the light source and light detector such that they detect probe presence through the probe well opening. This configuration allows the system to detect both the probe itself and the absence of debris blocking the light path, providing universal detection capability that is less susceptible to debris interference while maintaining automatic on/off functionality.
4Extent of automation
If an optical switch is used for automatic on/off mechanism, then the thermometer can be automatically powered on/off, but the alignment of light emitter and light detector makes the device complex and costly to assembly
Solution Approach 1:
The patent uses a flexible printed circuit board (FPC) to connect the light source and light detector, allowing for flexible routing and positioning of these components. This flexibility simplifies assembly by reducing the need for precise rigid alignment while maintaining the optical detection function for automatic on/off control.
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 solid-state activating system enhances reliability, reduces wear, conserves battery power, and minimizes interference from environmental factors, providing a more efficient and durable solution for power management in electronic thermometers.
Implementation Method 1
A solid-state activating system using a Hall-effect sensor and a magnet to automatically switch the thermometer between active and non-active states
Data Source
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AI summary
An electronic thermometer includes an automatic activating system for automatically configuring the thermometer between an active state (broadly, the thermometer is turned on) and a non-active state (broadly, the thermometer is turned off). In general the activating system includes a solid-state activating sensor, such as a Hall-effect sensor, in a housing of the thermometer and a magnet in a probe of the thermometer for activating the sensor when the probe is received in a probe well.