Solid-State Sensor Anti-Theft Thermometer Counter
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Solution Overview
Problem
Conventional anti-theft mechanisms in electronic thermometers, such as those using reed switches, are prone to mechanical wear and require bulky, expensive magnets, which are not reliable for long-term use.
Innovation Solution
A hand-held electronic thermometer with a microcontroller and a solid-state sensor that detects a magnetic field to reset an anti-theft counter, eliminating the need for moving parts and reducing the size and cost of the magnetic source.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a reed switch is used in the anti-theft mechanism, then the thermometer can be disabled after a predetermined number of uses, but the reed switch is prone to mechanical wear and failure
Solution Approach 1:
The patent replaces the mechanical reed switch with a solid-state magnetic field sensor. The sensor detects the presence or absence of a magnet to trigger the anti-theft counter reset, eliminating mechanical moving parts and contact wear. This substitution of mechanical system with a magnetic sensing system resolves the contradiction by providing both reliability and extended duration of action.
2Reliability
If a conventional magnet is used to activate the reed switch, then the anti-theft counter can be reset, but the magnet must have high flux density which makes it bulky and expensive
Solution Approach 1:
The patent changes the operational parameters of the magnetic system by using a solid-state magnetic field sensor that can detect weaker magnetic fields compared to what is needed for reed switch activation. This parameter change allows the use of smaller, lighter, and less expensive magnets while maintaining the anti-theft counter reset function, thus resolving the contradiction between reliability and weight/cost.
3Reliability
If a reed switch with glass vacuum tube is used, then the anti-theft mechanism can function, but the reed switch is fragile
Solution Approach 1:
The patent replaces the fragile mechanical reed switch housed in a glass vacuum tube with a solid-state magnetic field sensor. The solid-state sensor has no glass enclosure or moving parts, making it mechanically stronger and more resistant to shock and vibration while maintaining the anti-theft switch function. This resolves the contradiction between reliability and strength.
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 a reliable and cost-effective anti-theft system that extends the lifespan of the thermometer by reducing mechanical wear and eliminating the need for high-strength magnets, thus enhancing user safety and operational efficiency.
Implementation Method 1
A solid state sensor having no moving parts and in communication with the microcontroller is capable of detecting a magnetic field with a predetermined flux density to signal to the microcontroller to reset the anti-theft counter
Data Source
AI summary
A thermometry assembly includes a thermometer and a mount for mounting the thermometer on a wall or other support structure. The thermometry assembly has an anti-theft system for deterring theft of the thermometer. The anti-theft system generally includes a counter that counts the number of uses of the thermometer during a period beginning from the time the thermometer was last on the mount. A microcontroller of the thermometer is programmed to disable further operation of the thermometer when a threshold number has been reached or exceeded by the counter. The counter is reset when the thermometer is returned to the mount. The anti-theft system includes a solid-state sensor that is activated by a magnet in the mount. The sensor signals to the microcontroller to reset the counter when it is activated by the magnet.