Diseño e implementación de un protocolo de comunicación domótico para interacción entre sensores y actuadores

Abstract

Nowadays, the scenarios where human beings live are getting smarter. People want to improve their comfort by incorporating elements that facilitate or do more pleasant their stay. For this reason, the user requires that these elements be: easy, fast and safe to integrate into the environment.

In this work, a protocol was implemented on the application layer of the TCP / IP model. The protocol allows the interaction between sensors and actuators (client nodes) that run in a home automation network. A specific protocol is used in each layer: 1.) the IEEE 802.11 standard is used in the physical layer and defines basic aspects such as transmitter power and receiver sensitivity; 2.) in the second layer, CSMA / CA was used as medium access method, allowing multiple stations to use the same transmission medium; 3.) in the network layer, the interaction between the nodes is configured in mesh mode, where each node uses a 32-bit identifier based on its MAC address, typical of the protocol; 4.) the transport layer is configured using TCP, to ensure that the data is delivered reliably; finally, 5.) in the application layer the MQTT protocol is used.

To test the performance of the developed protocol, prototypes of the nodes were manufactured: actuator and sensor. An application was also developed for mobile devices based on Android, so that the user can control and manage the network from his device. In addition, it is proposed that the sending messages of the proposed protocol be secure and support attacks of a malicious nature, for which the AES-256 encryption algorithm is used.

The main advantages of the proposed protocol with respect to other protocols in the home automation area are: 1.) the simple way in which the information transfer is carried out through the MQTT protocol, minimizing the network overload; 2.) The easy incorporation of the nodes to the network using the mobile device application; and, finally, 3.) long-range communication and scalability in the network because the topology used allows the nodes to perform multi-hop.