DESIGN AND IMPLEMENTATION OF A MESSAGE SENDING SYSTEM OVER POWER LINES

In this study, a messaging system communicating over power lines was carried out based on microcontroller. the messages written on the keyboard are shown on the lcd (liquid cristal display) and sent over the power line simultaneously. these messages received through power line are displayed on the lcd in the receiver circuit. the message data are converted into message signals with microcontrollers in both transmitter and receiver circuits. digital data are converted into data signals with 140 khz frequency by using frequency shift keying (fsk) modulator/demodulator. the data signals are applied over the power line through a transformer and a capacitor called as a coupling circuit. in the developed power line communication (plc) system based on microcontroller, data transfer can be provided with adjustable signal frequency by existing power line cables without using additional cables with very low cost. these futures make the plc system attractive for the indoor communication system.