Continuous ECG Monitoring with Low-Power Electronics and Energy Harvesting

This paper presents a prototype of a wearable continuous electrocardiogram (ECG) monitoring device developed using commercial off-the-shelf (COTS) components. Taking advantage of low power electronics, this prototype device is fully powered from harvested energy. The prototype device also builds a bidirectional data communication link with an external data transceiver (TRx) via Bluetooth Low Energy (BLE) for wirelessly transferring digitized ECG data to and receiving user commands from the external data TRx. To minimize the power consumption of the device, efforts have been made on designing an ultra-low-power analog front-end (AFE) for amplifying and filtering of ECG signals and optimizing the microcontroller unit (MCU) firmware for sending the ECG data packets to the external data TRx at a throughput of 816 bits per second (bps). These received ECG data packets are communicated over USB to a PC, where a custom graphical user interface (GUI) decodes and displays the data packets in real-time. The user also sends start/stop commands, which trigger the wearable device to automatically stream the ECG data back to the GUI. We have characterized the functionalities of the energy harvesting, the AFE amplifying and filtering, and the wireless data transmission of the wearable device, and evaluated the entire system performance of conducting wireless ECG sensing.