Non-contact high-sensitivity alarm, design and application method based on human body capacitive sensing

Abstract

The invention discloses a non-contact high-sensitivity alarm based on human body capacitance induction, a design and a use method. Firstly, a formula between the sensitivity of a parallel plate capacitor and pole plate spacing is derived, and then the sensitivity of a variable pole spacing capacitor is obtained. An LC parallel circuit is constructed, the two ends of a capacitor of the circuit areconnected in parallel and a metal pole plate is led out, when the distance between a person and the metal pole plate changes, the value of the capacitance further changes, and the capacitance value ofthe capacitor is further determined by measuring the frequency of LC parallel resonance. Single linear interpolation is adopted to fit the linear relationship between induction capacitance and induction distance. When a human body is close to or far away from the metal pole plate, the capacitance value changes, so that the circuit resonance frequency changes, and thus an alarm is triggered. The non-contact high-sensitivity alarm adopts the LC parallel circuit resonance to measure resonance frequency and has the characteristics of high anti-interference capability, good environmental adaptability and the like, and the non-contact high-sensitivity alarm can be produced on a large scale and has great market potential.

Description

technical field [0001] The invention relates to a non-contact high-sensitivity induction alarm based on human body capacitance, its design and use method, which belongs to the field of electronic design and is used for anti-theft alarms on high-end exhibits. Background technique [0002] Anti-theft alarm has always been a necessary guarantee for maintaining social order. At present, with the development of televisions and cameras, closed-circuit monitoring systems have gradually grown. In the short decades of development of the closed-circuit monitoring system, along with the continuous impact of the new technology revolution, it has experienced one-to-one monitoring system, control circuit system, processor monitoring system, external multimedia monitoring system, transitional The stage of digital video surveillance system and digital media surveillance management system. [0003] The alarm detector is composed of a sensor and a signal processing circuit. It is used to de...

AI Technical Summary

Problems solved by technology

However, these sensors have the following disadvantages: (1) The detection range is small; (2) The installation of the sensor is obvious and not concealed enough; (3) The sensitivity of the sensor detection is not high enough; (4) False alarms may occur

However, places like large museums, auctions, high-end jewelry stores, etc., where valuables are often displayed, hope to use non-contact induction alarms that are small and difficult to be found. When a thief enters a certain distance from the item, the alarm will be triggered immediately. , and the thieves don't know where the alarm is hidden

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