The development of the IoT paradigm has significant contribution in the evolution of wide-ranging networks of connected devices. In the Connected Sustainable Home the IoT paradigm is revisited within the context of home automation and sustainability.

More specifically, in the Connected Sustainable Home we developed a web-based protocol built upon a Representational State Transfer (REST) structure. Following the principles of the Web of Things (WoT) the devices servicing the prototype are mapped into a web-based structure that uses an HTTP protocol for communication.

The prototype Connected Sustainable Home is probably the first fully implemented application of the WoT paradigm in home automation.

The house devices perform as nodes in a network, to meet goals independently or jointly. The HTTP protocol allows revisiting concepts of the web-based paradigm. For example, the mash up concept – used to collect information for web locations – was employed to collect information for physical devices in the house network.

Although, a mash up usually involves a simple service build on top of the communication layer – while the applications of the connected sustainable home are more multifaceted – using the HTTP protocol simplified the communication and enabled the residents to browse the house devices through a standard browser.

Establishing robust communication between the house devices and the control, and between devices and users is imperative in implementing the automation features of the house.

The implemented RESTful protocol supports the decision-making layer of the control, enables the communication and execution of performance plans, and allows the residents to interact with the house devices in intuitive ways.

The HTTP server receives requests from the devices and from the high-level control system and returns the requested information, or initiates the desired state change. The house devices are organized in a path structure, making possible to navigate through them with a common browser.

The optimization core of the prototype makes use of the house devices, as it would do a resident. For example, the tinting level of the programmable windowpanes on the south façade, and the desired levels of interior comfort – including temperature, humidity and light – are managed in a concerted manner by the optimization core, so that the desired levels of comfort are always maintained, while the long-term energy consumption is optimal.

A tablet-based user interface running on Android enables the interaction between users and devices. The WoT structure simplified the implementation of the Android application on top of the communication layer, since Android allows implementation for data processing in this structure.

A wide spectrum of applications can be developed based on the already implemented protocol. For example, connectivity in conjunction with systems-learning may in the future allow the control system to acquire learning capabilities – through the processing of patterns of use – and enable the catering of the occupants needs in increasingly more effective, non-intrusive ways.

Kotsopoulos, SD, Casalegno, F, Graybill, W, Recasens, A, 2014, “Developing a RESTfull Communication Protocol and an Energy Optimization Algorithm for a Connected Sustainable Home”,“1st International Conference on IoT in Urban Space (Urb-IoT2014)”, October 27 – 28, Rome, Italy.