Energy efficient heart rate sensing using a painted electrode ECG wearable

Abstract

Many countries are facing burdens on their health care systems due to ageing populations. A promising strategy to address the problem is to allow selected people to remain in their homes and be monitored using recent advances in wearable devices, saving in-hospital resources. With respect to heart monitoring, wearable devices to date have principally used optical techniques by shining light through the skin. However, these techniques are severely hampered by motion artifacts and are limited to heart rate detection. Further, these optical devices consume a large amount of power in order to receive a sufficient signal, resulting in the need for frequent battery recharging. To address these shortcomings we present a new wrist ECG wearable that is similar to the clinical approach for heart monitoring. Our device weighs less than 30 g, and is ultra low power, extending the battery lifetime to over a month to make the device more appropriate for in-home health care applications. The device uses two electrodes activated by the user to measure the voltage across the wrists. The electrodes are made from a flexible ink and can be painted on to the device casing, making it adaptable for different shapes and users. In this paper we show how the ECG sensor can be integrated into an existing IoT wearable and compare the device's accuracy against other common commercial devices.

Performance of graphene ECG electrodes under varying conditions

“…For each collected record we analyze both the Signal-to-Noise Ratio (SNR) and the bpm error of the ECG against the reference PPG device. To process the ECG record, we apply standard ECG signal processing, the steps of which are described in detail in [2]. In summary, our first step was to remove 50 Hz mains interference.…”

“…However, this only gives limited information on the heart activity, typically just the heart rate. Wearable Electrocardiogram (ECG) units are starting to appear [1] but placing these at the wrist is challenging [2]. For this reason wearable ECG units often taken the form of smart garments such as T-shirts.…”

ECG Monitoring Systems: Review, Architecture, Processes, and Key Challenges

“…Other studies proposed special low-cost circuit designs [247]. Reducing the cost could also be achieved by using a low-cost wearable devices for signal acquisition, especially in IoT-based systems [248,249]. Other low-cost devices were used, such as portable ECG monitoring devices in [250,252].…”

A Systematic Literature Review of the Factors that Influence the Accuracy of Consumer Wearable Health Device Data

“…Conversely, longer battery life is commonly associated with bigger size devices [47,48]. Additional strain is placed on the energy requirements of CWHDs due to continuous collection and exchange of physiological data between a CWHD, other connected IoT devices and applications (apps) [49].…”