WoT on The Extreme Edge (WoTTEE): Enabling W3C Web of Things for Micro-controllers

Edge computing has emerged as a viable approach to minimize the latency of time-critical Internet of Things (IoT) applications. The new frontier of research is to offload tasks directly on micro-controllers, i.e. on the same device generating the sensory data. However, this approach requires to cope with to the limited computational capabilities of the devices and consequently to adapt existing techniques and tools to the extreme edge. In this paper, we contribute to this research direction by investigating how to enable W3C Web of Things (WoT) capabilities on micro-controllers, for increased performance and interoperability purposes. Given the excessive complexity of the original proposal, we propose a revised architecture of the Web Thing (WT) that can fit the limited resources of constrained devices while maintaining the compatibility with the WoT standard. Then, we present the WoTTEE framework, a software suite that supports and facilitates the deployment, installation and monitoring of edge-oriented WTs. Finally, we validate the operations of WoTTEE in a small testbed and demonstrate the capability to support adaptive IoT systems where micro-controllers are able to dynamically switch among different IoT network protocols thanks to the Thing Description (TD) mechanism of the W3C WoT.