Using the I2C bus to set up Long Range Wired Sensor and Actuator Networks in Smart Buildings

The Inter Integrated Circuit (I2C) is one of the most common standards for serial data transmission between microcontrollers, microprocessors and peripheral devices. Nowadays, many off-the-shelf devices are provided with an I2C interface, that can be then the easiest way to connect them to other devices through a wired connection, regardless from their features. While the setup of intelligent distributed architectures for Smart Buildings based on wireless communication channels may be straightforward, the chance to set up local area wired networks based on the I2C bus may be of great interest for example in case of noisy environments. Nevertheless, I2C is characterized by a very short range, with transmission distances generally lower than 10 m. The aim of this paper is then to suggest the use of the I2C bus for the realization of wired local area sensor and actuator networks, setting up a multi-Master and multi-Slave network architecture with transmission ranges up to 100 m. For this reason, the paper focuses on the problem of parasitic capacitances, proposing a possible hardware solution to deploy such a kind of architecture based on the use of ad-hoc components. At the same time, in order to propose a flexible architecture, the paper describes a novel solution to allow the transparent connection to the network of additional devices, avoiding the risk for address conflict.