In this technological world, automatic systems are being preferred over manual system. In this series Home Automation plays an important role for humans. In this unit we talk about basic needs to understand the project well and also for its future advancements. We are going to talk about different types of sensors (i.e. Temperature Sensor, LPG Gas Sensor, LDR) and input and output devices (i.e. 2x2 matrix Keypad, Buzzer, DC Motor, 16x2 Char LCD Display, Power Supply section etc.).Now we are going to Interface all those with the brain of the system ‘Microcontroller (i.e. ATmega16/16L)’ and let’s find out what the individual role of each component are and how they act as Smart Home System together. In this project I used three analog sensors i.e. Temp, LPG Gas and LDR. These are given analog output. Read more to find out how the circuit looks like and what is the code.