A New Keyboard Key Sound Detection System

With the improvement of people's living standards,people's quality requirements for keyboard keys are getting higher and higher.Due to the different production process,test environment and test standards of the keyboard,it is necessary to develop a keyboard key tone sound detection system.The first chapter of this paper introduces the development of the keyboard key noise detection system:the initial keyboard key noise detection is manual online detection,this detection method is subjective and inefficient;then the researchers developed a silent motor knock by pressing the keyboard button,the quality of the keyboard button is judged by analyzing the decibel value of the button sound of the keyboard button.This detection method needs to be carried out in a silent room,which is harsh on the environment,and the silent motor is relatively expensive,and the production cost of the device is high.Therefore,the industrial utilization rate is low;on this basis,this paper proposes a new keyboard key sound detection system,which optimizes the detection system from the aspects of tapping mode and signal acquisition environment,and improves the industrial utilization rate of the same type of equipment.In addition,based on phase control,this paper designs a puzzle-type acoustic metamaterial that realizes acoustic wave manipulation.The theoretical and experimental aspects realize the generation of broadband self-bending acoustic beam,which provides a new idea for wide-band acoustic wave control.The second chapter introduces some theoretical foundations of the work of this thesis,including the multiple relationship of the inverse amplification circuit with filtering function,the theoretical derivation of the sound insulation effect of the single-layer acoustical wall and the a-weighting algorithm used in signal processing.The work laid the theoretical foundation.The third chapter proposes a new keyboard key sound detection system,which is optimized on the tapping method.It is different from the traditional silent motor knocking keyboard.This article uses the analog signal to drive the electromagnet to simulate the finger tapping the keyboard button.The tapping method reproduces the process of tapping the keyboard button when the keyboard is actually used,thereby ensuring the reliability of signal detection.The abnormal sound detection system is composed of a signal acquisition system and a signal analysis system.The signal acquisition system includes a circuit system and a software system.The circuit system mainly includes a digital circuit part,an analog circuit part,a power circuit part and a communication part.To ensure the stability of the circuit system operation,the HCNR200,6N137,PVI1050N optical isolation chips will be used in this chapter respectively.Different circuit parts are isolated to prevent electrical signal interference between different circuit modules.The software system is a microcontroller program used to control the signal acquisition system.The signal analysis system is a signal analysis system based on the a-weighted network.In addition,in order to ensure the effectiveness of signal acquisition in the natural environment and improve the industrial utilization rate of the equipment,this chapter first reduces the interference of environmental noise on signal acquisition by reducing the signal acquisition distance,and then adds a soundproof cavity for isolating the ambient noise.The soundproof cavity is divided into two parts.The large outer box uses the mass sound separation law to isolate the higher frequency ambient noise.The structural characteristics of the narrow small cavity inside can isolate the low frequency ambient noise.With these two sound insulation measures,the environmental noise isolation of 0-20000 Hz can be realized,and the validity of the keyboard key sound collection is ensured,which provides a guarantee for subsequent signal analysis.The method is advantage for large-scale industrial use of the same type of equipment,and can greatly reduce the production cost of the equipment.The fourth chapter compares the signal waveform and decibel value of the same keyboard button,and proves the stability of the system.On this basis,the signal waveforms of the eight qualified keyboard buttons,the spectrum diagram and the corresponding sound pressure level value decibels are compared.In addition,this paper also made research on super-material acoustic wave manipulation.The appendix proposes a puzzle-type ultra-wideband acoustic wave control structure,which now controls the self-bending of acoustic wavefront in two dimensions.In this research work,the phase distribution of the acoustic wave of the target beam is first deduced.The groove-like acoustic metamaterial is used as the unit structure for phase distribution.Then the finite element simulation and experiments are used to verify the acoustical acoustics at different frequencies.The self-bending control effect of artificial materials on sound waves.Finally,this paper theoretically demonstrates that the working frequency band of this acoustic artificial structure can be broadened by adjusting the width of the groove cross section.For example,the working frequency band can be extended by reducing the width of the unit structure cross section.The upper limit.This method provides a new idea for the design of ultra-wide band acoustic functional devices,and it also has potential application value in medical ultrasonic diagnosis,ultrasonic imaging and non-destructive testing.In summary,this paper proposes a new type of keyboard key sound detection method,which optimizes the tapping method and the method of adding the soundproof cavity to ensure the reliability of signal acquisition and realize the signal acquisition under strong background environment noise.It improves the industrial use rate of the same type of equipment.In addition,the acoustic-based manipulation of sound waves based on the acoustic artificial metamaterials in this paper realizes the wide-band acoustic wave self-bending sound wave manipulation.This simple and effective acoustic artificial metamaterial is ultra-wide band.The design of self-bending devices provides new ideas.