Low-power Consumption Individual Noise Exposure Protection Device

Noise in the environment will affect people's normal work,study and rest.Excessive noise will also damage people's hearing and visual organs and cause mental illness.Sound sources,transmission pathways and receptors are three factors that cause noise hazards.When it is impossible to eliminate sound sources and hinder their transmission,they need to timely transfer receptors to avoid excessive noise.Therefore,noise needs to be monitored in real time.In traditional noise measurement instruments,audio signals need to be processed by a series of analog circuits such as amplification circuits,weighted networks,detectors,logarithmic amplifiers,and integrator circuits.The circuit structure is complex,it requires high precision components,it is difficult to debug,the power consumption is high,the volume is large.This topic has designed a new low-power individual noise exposure protection device,the main content is as follows:The digital scheme of the device was proposed.The MEMS digital microphone with pulse density modulation(PDM)interface was used to collect the noise.The digital signal processing technology was used instead of the analog circuit to realize the noise signal processing and the noise dose was monitored.low-power individual noise exposure protection device was designed.The device is mainly composed of MEMS digital microphone,memory,interface conversion circuit,user buttons,alarm LED,MCU and power module.The device selection and low-power circuit design have been completed,and the degree of peripheral drive has been designed,and the noise signal has been fully digitized,completing the device's low-power software design.According to the characteristics of the noise dose accumulation process,the noise with low sound intensity has a low impact on the 100%dose,and a noise dose accumulation scheme based on the sound intensity threshold trigger is proposed.A sound intensity threshold trigger circuit scheme and corresponding software scheme are designed so that the device can automatically adjust the working mode according to the change of sound intensity in the environment.Build a test platform to measure the current status of each device and the whole device,and compare the sound intensity levels of the device and the NP-DLX in single frequency and mixed state.The test shows that the current specification of each device is basically consistent with the manual,the whole working current is less than 8mA,and the sound level error is less than 1dB during mixing test.