Flood Transmission based Protocol for Home Automation System via Power Line Communication Rozeha A. Rashid, Mohd Adib Sarijari, Mohd Rozaini Abd Rahim, Tan Zun Yang Faculty of Electrical Engineering, University of Technology Malaysia Skudai, Johor rozeha@fke.utm.my Abstract There are many researches and development involving the use of power line as data transmission medium. With multiple power outlets in almost every room in every house, the power line is the most pervasive network and the largest infrastructure available. The aim of this project is to deploy this infrastructure in designing a home automation system. This paper presents a method to develop a home automation system using the AC (alternating current) power line to establish a network between main controlling unit and client units with a proprietary designed power line communication (PLC) protocol. The designed protocol has features such as multinode simplex communication, flood transmission and even parity error detection. The protocol is successfully implemented and tested in a home automation system consisting of one main controlling unit and three client units. Each client unit is able to control three electrical devices. Multipoint of receiver units can be controlled (On / Off) by the main controller unit sending command data using power line as transmission medium to the corresponding devices. Keywords: Power line communication, multinode communication, flood transmission, parity checking. I. INTRODUCTION Digital communication over the power line called power line communication (PLC) has become an excellent opportunity for the energy providers (utility corporations) to implement new services, both for the utilities and for their customers. As power line network is the most enormous and wide-spread network with huge, unmatchable scale, PLC will become more important in modern communication technology, and would possibly become the replacement for present telephone network, cable TV network and residential internet network eventually [1]. This "four in one" system will hugely reduce the initial investment of network construction [2]. Smart home technology is one of the specialized applications where power-line communication can be a key technology. By considering these advantages of power line as a transmission medium, a new network protocol is designed to suit the needs of a home automation system which is sustainable in the noisy environment of power line communication. The question is; what does a home automation system need? Firstly, home automation system needs more than one electrical device to be controlled at a time. Otherwise, consumer would not be delighted. Thus, the designed protocol must include multinode capability; which means a main controlling unit can simultaneously support multiple nodes. Figure 1. Block diagram of home automation system via power line Figure 1 shows a block diagram of a basic home automation system via power line. The main controller unit, consisting of a microcontroller, will send command data using power line as transmission medium to control the corresponding devices. The built system has one main controlling unit and three client units. Each client unit is able to control three electrical appliances. Hence, for this particular system, AC Power line Switch Microcontroller ASK Modulator Microcontroller Devices Coupling Network Coupling Network ASK Modulator