Public healthcare has been paid an increasing attention given the exponential growth human population and medical expenses. It is well known that an effective health monitoring system can detect abnormalities of health conditions in time and make diagnoses according to the gleaned data. As a vital approach to diagnose heart diseases, ECG monitoring is widely studied and applied. However, nearly all existing portable ECG monitoring systems cannot work without a mobile application, which is responsible for data collection and display. In this paper, we propose a new method for ECG monitoring based on Internet-of-Things (IoT) techniques. ECG data are gathered using a wearable monitoring node and are transmitted directly to the IoT cloud using Wi-Fi. Both the HTTP and MQTT protocols are employed in the IoT cloud in order to provide visual and timely ECG data to users. Nearly all smart terminals with a web browser can acquire ECG data conveniently, which has greatly alleviated the cross-platform issue. Experiments are carried out on healthy volunteers in order to verify the reliability of the entire system. Experimental results reveal that the proposed system is reliable in collecting and displaying real-time ECG data, which can aid in the primary diagnosis of certain heart diseases.
Mimicking the pressure-sensing behavior of biological skins using electronic devices has profound implications for prosthetics and medicine. The developed electronic skins based on single response mode for pressure sensing suffer from a rapid decrease in sensitivity with the increase of pressure. Their highly sensitive range covers a narrow part of tolerable pressure range of the human skin and has a weak response to the injurious high pressures. Herein, inspired by a bioluminescent jellyfish, we develop an electronic skin with dual-mode response characteristics, which is able to quantify and map the static and dynamic pressures by combining electrical and optical responses. The electronic skin shows notable changes in capacitance in the low-pressure regime and can emit bright luminescence in the high-pressure regime, which, respectively, imitates the functions of the mechanoreceptors and nociceptors in the biological skin, enabling it to sense gentle tactile and injurious pressure with sensitivities up to 0.66 and 0.044 kPa, respectively. The complementary highly sensitive sensing ranges of the electronic skin realize a reliable perception to different levels of pressure, and its mechanically robust and stretchable properties may find a wide range of applications in intelligent robots.
Long Range (LoRa) network is emerging as one of the most promising Low Power Wide Area (LPWA) networks, since it enables the energy-constraint devices distributed over wide areas to establish affordable connectivity. However, how to implement a cost-effective and flexible LoRa network is still an open challenge. This paper aims at exposing a feasible solution of design and implementation, allowing users to conveniently build a private LoRa network for various IoT applications. Firstly, several typical application scenarios of LoRa network are discussed. Then, the LoRa system architecture is presented with the functionality of each component. We address the hardware design and implementation of LoRa Gateway, which is the bridge between LoRa nodes and LoRa network server. Especially, the paper contributes by proposing an improved software architecture of LoRa network server whose source codes are open on GitHub. Under the architecture, LoRa network server is divided into four decoupled modules and uses the messaging system based on streaming data for the interaction between modules to guarantee scalability and flexibility. Finally, extensive experiments are conducted to evaluate the performance of LoRa networks in typical environments.Abstract-LoRa, LPWA, IoT, Microservice, Open Source
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