Abstract
In recent years, the improvement of wireless protocols, the development of cloud services and the lower cost of hardware have started a new era for smart homes. One such enabling technologies is fog computing, which extends cloud computing to the edge of a network allowing for developing novel Internet of Things (IoT) applications and services. Under the IoT fog computing paradigm, IoT gateways are usually utilized to exchange messages with IoT nodes and a cloud. WiFi and ZigBee stand out as preferred communication technologies for smart homes. WiFi has become very popular, but it has a limited application due to its high energy consumption and the lack of standard mesh networking capabilities for low-power devices. For such reasons, ZigBee was selected by many manufacturers for developing wireless home automation devices. As a consequence, these technologies may coexist in the 2.4 GHz band, which leads to collisions, lower speed rates and increased communications latencies. This article presents ZiWi, a distributed fog computing Home Automation System (HAS) that allows for carrying out seamless communications among ZigBee and WiFi devices. This approach diverges from traditional home automation systems, which often rely on expensive central controllers. In addition, to ease the platform’s building process, whenever possible, the system makes use of open-source software (all the code of the nodes is available on GitHub) and Commercial Off-The-Shelf (COTS) hardware. The initial results, which were obtained in a number of representative home scenarios, show that the developed fog services respond several times faster than the evaluated cloud services, and that cross-interference has to be taken seriously to prevent collisions. In addition, the current consumption of ZiWi’s nodes was measured, showing the impact of encryption mechanisms.
Highlights
The Internet of Things (IoT) paradigm proposes the interconnection of physical devices through networks that allow for sharing data and for controlling their capabilities in real time
It is important to note the different nature of both types of home automation devices present in the architecture: in most home automation systems, sensors tend to be more numerous than actuators and send frequent data updates, while actuators only operate on specific occasions
This article presented ZiWi, a low-cost IoT fog computing Home Automation System (HAS) that allows for carrying out seamless communications among ZigBee and WiFi nodes
Summary
The Internet of Things (IoT) paradigm proposes the interconnection of physical devices through networks that allow for sharing data and for controlling their capabilities in real time. The designed architecture, together with the use of an open messaging protocol like Message Queuing Telemetry Transport (MQTT) to communicate nodes, make ZiWi more flexible than traditional home automation solutions, whose manufacturers are often reluctant to offer connectivity with third-party systems Such an openness and the use of widely known technologies provide robustness and ease of construction and deployment, being straightforward for integrating new elements on the ZiWi IoT ecosystem and allowing the user to make use of a wide range of resources to act on devices to obtain information on them or to automate certain events.
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