Design And Implementation Of Sleep Monitor Based On Heart Rate Signal

The public awareness of health is increasing in recent years,in that the sleep issue has become one of the most popular concerns around people.Sleep issue could cause both physical and psychological side effects on people's bodies;therefore,it is important to monitor sleep quality as well as to find whether sleep disorder exists.Due to those limitations such as complex equipment,large size and complicated operation,the traditional sleep monitor equipment cannot become benefit for the public.Accordingly,it is necessary to develop such a simple,low cost and lightweight monitoring equipment.Portability and practicality have become two strong factors for sleep monitoring devices.Therefore,the sleep monitor designed and implemented in this paper based on the concept listed above is going to serve the public in the future hopefully.In view of portability and practicality,this paper designs and implements a portable sleep monitor based on heart rate signal,which divides the sleep into phases using the difference of heart rate.In order to improve the accuracy of sleep phase,the sleep monitor also draw support from wrist activity signal to judge the awakening period.The sleep monitor takes microprocessor STM32F103 as a digital processing unit,uses both a heart rate sensor SON1303 and an inertial sensor MPU6050 externally as data collection module.Besides,it includes the display screen and external keyboard.The sensor STM32F103 is used as extracting the value of heart rate,and the inertial sensor MPU6050 uses the Orientation Angle Algorithm to collect the frequency of the wrist activity.The heart rate frequency and wrist activities during the whole night are made use of designing and implementing a Sleeping Phasing Algorithm.The result of phased sleeping could be collected and shown through the display screen,including the sleep process state figure,sum sleep time and time information for each phase.The Sleeping Phasing Algorithm divides the sleep process into three phases: Awakening,Rapid Eye Movement and Non-Rapid Eye Movement.The Non-rapid Eye Movement can be further refined into Deep Sleep and Shallow Sleep.Compared to the sleep monitoring results of wearable devices on sale for now,the Phasing Algorithm is more suitable with the international standards for sleep phasing.Besides,the algorithm can further refine the sleep processes,the obtained total sleep time and deep sleep time have high consistency.After testing and verification with the system,the sleep monitor designed in this paper can operate normally and complete the expected function.As to the contrast with the wearable device on the market,the results prove the validity of sleep phasing.The sleep monitor can help users to know their sleep status opportunely as well as find and solve sleep issues as early as possible.The monitoring provides a practical technical measure for objective sleep quality evaluation and is suitable for promotion and popularization.