This project based on DTMF(Dual Tone multi frequency) which generates in cellular cell phones. By using this thing of cell phone we control the home appliances from anywhere in the world(In Network Area). Below you can see the diagram of DTMF keypad. When we press any key then it generates a frequency after mixing two frequencies. And then send it to the receiver end over communication channel.
User can activate their devices using this DTMF keypad as he/she want to activate. The encoder encodes the user input and sends via a communication channel. The receiver receives the modulated signal and demodulates it and the user input. In this system, we are going to make a DTMF based home/office appliance. How is the PCB Designed? What dimensions of the code are kept in mind? Continue reading to know more.