WE-Safe: A Self-Powered Wearable IoT Sensor Network for Safety Applications Based on LoRa
Poor environmental conditions can lead to severe health problems. It is essential to develop effective, reliable, and fast response systems for people working in hazardous environments. This paper presents a wearable Internet of Things (IoT) sensor network aimed at monitoring harmful environmental conditions for safety applications via a Lora wireless network. The proposed sensor node, called WE-Safe node, is based on a customized sensor node, which is self-powered, low-power, and supports multiple environmental sensors. Environmental data is monitored by the sensor node in real-time and transmitted to a remote cloud server. The data can be displayed to users through a web-based application located on the cloud server and the device will alert the user via a mobile application when an emergency condition is detected. The experimental results indicate that the presented safety monitoring network works reliably using energy harvesting.
WEARABLE sensor nodes are generally deployed in wireless body area networks (WBAN) to monitor physiological parameters, such as body skin temperature, photoplethysmogram (PPG), or electrocardiogram (ECG) . In addition to medical signals, they can be deployed to monitor environmental conditions around the human body as well, such as in the safety application , and environmental monitoring applications. Such a wearable sensor system can also provide invaluable and useful information about the environmental impact on subjects’ health. People can also gain a deeper understanding of their local micro-environment. A wearable system is not only limited to personal use, it can also be installed on a bicycle, car, and animal to form a wearable or mobile wireless sensor networks. For example, in , a mobile node is installed on bicycle for environmental monitoring. The power supply of sensor nodes is a major challenge for autonomous wearable sensor nodes, because many devices require regular battery replacement or charging. To allow long-term operation and minimize the human interaction of the wearable sensor node, the system has to be low power consumption and adopt energy harvesting . There is a need for an efficient and effective energy harvesting module, which can address this power supply issue. There are several options for energy sources, such as thermoelectric, piezoelectric, micro-magneto-electric, or photoelectric harvesting techniques . Solar energy provides the highest power density among these with high output voltages .
The drawback is that the solar energy will disappear at night and this should be considered in the power management unit of a sensor node.
PRPOSED SYSTEM :
The proposed sensor node, called WE-Safe node, is based on a customized sensor node, which is self-powered, low-power, and supports multiple environmental sensors. Environmental data is monitored by the sensor node in real-time and transmitted to a remote cloud server. The data can be displayed to users through a web-based application located on the cloud server and the device will alert the user via a mobile application when an emergency condition is detected. This paper presents a self-powered wearable IoT sensor network, named as WE-Safe IoT project, for safety environmental monitoring. Each sensor node consists of a micro power manager, a sensing unit, and a wireless module. The micro-power manager is designed to harvest energy both indoors and outdoors to enable a continuous energy supply for the sensor node. The total sensor node is low power consuming 5.6 μA in sleep mode. The data collected is transmitted to a gateway via a long-range LoRa wireless technology.
This paper presents a self-powered wearable IoT sensor network system for safety applications (WE-Safe project). Surrounding environmental data is collected and sent to a remote cloud via the LoRa network. The micro-power manager is able to harvest solar energy from both indoor and outdoor environments to enable a continuous energy supply for the sensor node. The aim of this paper is to provide an effective and convenient solution for people working in harsh environments. The experimental results show that the system can provide reliable and real-time data. Such an IoT platform will also present new opportunities for preventing health issues especially for people subjected to harsh environments.
Currently, the gateway is only used to forward the message from the wearable network to the cloud service. In the future, the work can be improved by by utilizing the gateway to send control messages to wearable sensor nodes in order to control the duty-cycle, transmission data rate, and transmission power according different applications’ requirements. The gateway can also enable edge computing to support time-dependent applications, so as to improve the network’s reliability and availability.