Reducing Electric Power Consumption When Transmitting ECG/EMG/EEG Using a Bluetooth Low Energy Microcontroller

Low-power wearable sensors now have sufficiently high sampling rates and bandwidth to support acquisition of electrophysiologic signals (e.g., ECG/EMG/EEG) [1–3]. But, these higher sampling rates are associated with higher power consumption, greatly reducing battery life [4, 5]. Thus, we examined average power consumption in a commercial Bluetooth low energy microcontroller (TI CC2640R2 BLE Module) while varying transmission power (maximum vs. minimum available), time interval between transmissions (10 ms to 5 s), sampling frequency (1000 to 4000 Hz), and transmit payload size (all samples vs. one “processed” value per interval); since each of these variants can influence power consumption [6, 7]. Neither sampling rate nor payload size noticeably altered power consumption. Increased transmit power, as expected, increased power consumption. Longer transmit intervals reduced power consumption, with most of this advantage occurring by intervals as small as 50–100 ms. Thus, relatively low latency (≤ 100 ms), low power signal acquisition is supported by these commercial modules, without particular regard to payload size or sampling rate.