The Android Smartphone’s ECG Monitoring System Based On Bluetooth4.0

With prevalence rate of cardiovascular disease moving in uptrend, the demand of monitoring patients’ECG parameter during24hours has become in urgent need. The hospital’s electrocardiograph has the shortcomings of immense size and working place limitation, and the portable ECG monitor sold in the market with integration of hardware and software which inevitably increase its size and price, both of the two kinds of device is insuited to be spread to home and personal’s mobile demand. The wide spread of smartphone is a chance to make ECG data collecting device lighter and slimer, and the app client on Android and iOS can also bring user better sight experience and access remote cloud server more easily. For power consuming reducing ability and becoming standard smartphone interface of the bluetooth4.0low energy protocol, The designed ECG monitoring system can be the new trend of mobile health product.Firstly, the paper outlines the development process of existed ECG monitor product, signal preprocess, feature recognition and online-diagnosis aspects.Secondly, the cause of ECG wave and signal sampling circuit design are introduced. The project uses24-bit A/D converter ADS1298to detect weak signal. And resistance to common mode voltage, overvoltage protection, noise filtering is being considered,. Alos, how to configure and use ADS1298is being explained.Thirdly,2.4GHz radio hardware design and bluetooth4.0low energy protocol is explained. The BLE protocol optimizes the physical channel and inter layer operation mechanism so that bring down the power consumption, and developer should pay more attention to GAP and GATT layer. Then, bluetooth low energy chip CC2540which runs OSAL multi-task OS is introduced, and how to sample ecg data and realize bluetooth4.0transmission between Android and CC2540is explained.In the signal preprocessing part, the superiority of muti-scale space analysis thoughts based on wavelet transform is outlined. Then, the Mallat algorithm which largely improves computing efficiency on Embedded platform is elaborated, and based on which, the paper uses wavelet filtering method to denoise baseline shift, power line interference and myoelectricity interference.In the feature extraction and online diagnosis part, the wavelet transform modulus maxima theorem related to Lipschits index for detecting singularity is applied to distinguish QRS wave in ECG, and a different way called united-detecting method combined continuous wavelet transform and differential threshold arithmetic is used to recognize summit of R wave, based on which, then beginning of Q wave and end of S wave are also found out. After QRS wave and heart rate information are picked up, the app can do auto diagnosis for beat abnormal such as ventricular premature beat and cardiac arrest, also for some heart rate abnormal symptom.Next, Android client-side application development is introduced. The software includes real-time drawing of processed data from bluetooth low energy notification interface, file store, SQLite database for basicuser information and medical record, how to process ecg data and realize on-line diagnosis by Java, and UI design.Finally, in order to achieve immediate diagnosis result feedback and make sure safety of patients’life, the auto SMS sending and email notifying function are added to the app, the doctor and patient’s relative can do remote monitoring for him and get his health state in time.