A Bluetooth low energy approach for monitoring electrocardiography and respiration

This paper presents a design and a contrast test of an ultra-low power wireless health monitoring system capable of measuring a subject's ECG (Electrocardiography), respiration, and body temperature. The system is based on the BLE (Bluetooth Low Energy) technology which is most valued for its ultra-low power consumption. Compared to our former design using MSP430 MCU and Bluetooth 2.1, this new design is much more highly integrated and can reduce power consumption significantly, which is generally a vital problem should be considered in WSN (Wireless Sensor Network) issues. The new system can save as much as nearly 75% power consumption than the former design when working in the same mode with the sampling rate at 250 Hz, which means that the battery life can extend to 107 hours compared to 26 hours of the former one, both using a 3.7 V lithium polymer battery with the capacity of 1100 mAh. Meanwhile, the new design can connect 3 nodes simultaneously with a single PC or smart phone wirelessly; this number may increase with the new BLE stack will be released in the future.