Design Of Integrated Hearing Detection System Based On STM32 And Android

Otoacoustic emission(OAE)and auditory brainstem response(ABR)are objective and common methods,which are used in clinical hearing detection.OAE is an audio signal,which produced in the cochlea and release to the external audiotory canal through the ossicular chain and tympanic membrane.OAE is an objective and noninvasive detecting method for cochlea,therefore OAE has been used in clinical neonatal hearing screening,auditory system disease diagnosing and so on.ABR is a bioelectric signal,which measured between forehead and mastoid after acoustic stimulation.ABR reflects the health status of auditory nerve,which could be used in clinical neonatal hearing screening,retrocochlear diseases diagnosing and so on.OAE is just used to detecting the function of cochlea,but ABR is just used to detecting the function of auditory nerve,so they always been used both for hearing detection in clinical.The detecting methods of OAE and ABR both are collecting signal after acoustic stimulation,which are similar.However now the OAE detection and ABR detection always been completed by independent devices,and the devices are monopolized by foreign manufacturers and expensive.Computers are been used as the platform for data processing,data present and human-computer interaction in the conventional medical devices.But computers are too large to be portable,computers are high power consumption and the cables of computers may affect the medical signals.As the development of mobile internet and the emergence of mobile smart devices,mobile medical devices has been rising,which combine the conventional medical devices.But there is no OAE and ABR detection system based on mobile smart devices in domestic market.Based on the above reasons,this paper introduced a design of a portable hearing detection system,which have the function of detecting both OAE and ABR and based on STM32 MCU and android mobile phone.The system main contains a slave computer and a host computer,the slave computer's core is the STM32 MCU and the host computer is a android mobile phone.Firstly,The slave computer generates stimulus sound controlled by the android mobile phone.Then,the sensors collect signal for slave computer.Thirdly,the slave computer process data and send results to mobile phone by bluetooth.At last,the phone presents the result and storage the data.This paper detailedly introduced the hardware design and the software design of the system.The rules of the hardware design are highly integrated and low noise.The hardware contain power circuit,the STM32 MCU circuit,stimulus sound generating circuit,OAE pretreatment circuit,ABR pretreatment and driver circuit,ADC and signal isolation circuit,impedance measurement and signal isolation circuit,bluetooth module circuit.The software of the system contains firmware program and android application.The firmware program contains controlling part and signal processing part.The controlling part is used for playing stimulus sound,the collection of OAE and ABR signal,the measurement of impedance,the transport of signal,and so on.The signal processing part is used for OAE and ABR signal processing.The android application contains human-computer interaction module,bluetooth connection,data storage,and so on.Finally,this paper proves the feasibility and effectiveness of the design by experiments which are noise test,stimulation and impedance test,synchronization test,OAE and ABR detection tests.The results indicate the system could be used to complete OAE and ABR detection tests.