Abstract
Many innovative services are emerging based on the Internet of Things (IoT) technology, aiming at fostering better sustainability of our cities. New solutions integrating Information and Communications Technologies (ICTs) with sustainable transport media are encouraged by several public administrations in the so-called Smart City scenario, where heterogeneous users in city roads call for safer mobility. Among several possible applications, recently, there has been a lot of attention on the so-called Vulnerable Road Users (VRUs), such as pedestrians or bikers. They can be equipped with wearable sensors that are able to communicate their data through a chain of devices towards the cloud for agile and effective control of their mobility. This work describes a complete end-to-end IoT system implemented through the integration of different complementary technologies, whose main purpose is to monitor the information related to road users generated by wearable sensors. The system has been implemented using an ESP32 micro-controller connected to the sensors and communicating through a Bluetooth Low Energy (BLE) interface with an Android device, which is assumed to always be carried by any road user. Based on this, we use it as a gateway node, acting as a real-time asynchronous publisher of a Message Queue Telemetry Transport (MQTT) protocol chain. The MQTT broker is configured on a Raspberry PI device and collects sensor data to be sent to a web-based control panel that performs data monitoring and processing. All the architecture modules have been implemented through open-source technologies. The analysis of the BLE packet exchange has been carried out by resorting to the Wireshark packet analyzer. In addition, a feasibility analysis has been carried out by showing the capability of the proposed solution to show the values gathered through the sensors on a remote dashboard. The developed system is publicly available to allow the possible integration of other modules for additional Smart City services or extension to further ICT applications.
Highlights
Internet of Things (IoT) and related technologies have been undergoing exponential growth for a few years, rising from 15 billion connected devices in 2015 up to 30 billion in 2020, and their numbers are intended to grow over the decade [1]
In contrast to the previous approaches, we aim at: (i) developing an E2E solution able to convey the Vulnerable Road Users (VRUs) data acquired through external sensors and/or smartphone-embedded sensors toward a centralized premise; (ii) exploiting multiple wireless technologies so as to optimize different links; (iii) exploiting a pub-sub paradigm through the Message Queue Telemetry Transport (MQTT) protocol, enabling a logical decoupling between source and destination; (iv) using open-source technologies in order to build a core system where additional plug-in can be added for enabling scenario-specific solutions
Android apps can send or receive broadcast messages from the Android system to the publish/subscribe design pattern we find in network protocols, such as MQTT
Summary
Internet of Things (IoT) and related technologies have been undergoing exponential growth for a few years, rising from 15 billion connected devices in 2015 up to 30 billion in 2020, and their numbers are intended to grow over the decade [1]. Deploying a large number of wearable devices all over the city would have a large impact on the costs of such a system; we deem that, cost-wise, a full-stack solution including all the elements for complete control of the system from the source to the customer premises would be highly beneficial as it allows cutting off all those costs linked to third-party software and hardware, which an IoT solution usually relies on Another reason for cost reduction is the presence of an open-source approach where, once the community is fully engaged, the rate of progress can rapidly accelerate, and the project can potentially progress at a rate that can overcome closed-source development [1]. An End-to-End (E2E) Open-Source Proof-of-Concept (PoC) IoT architecture is proposed here, aiming to properly address the previously introduced issues It is based on the integration of different open-source technologies, whose main purpose is to monitor, through the use of sensors connected to a micro-controller, the information related to the road users.
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