In recent years people, tend to use smart devices and live in smart buildings to facilitate our day by day actions. Nevertheless, digital electronics components are becoming popular and advanced than the analog, and the world is becoming modernized digital world. Smart buildings use very advanced technology in order to control devices automatically. However, we are still facing problems while forgetting some devices turned on while we left the building which consumes energy a lot. Additionally, elder people are facing difficulties to move for switching off / on devices (AC, lighting, TV, and washing machine). Also, sometimes we wish if we can turn on the AC before arriving to the building especially with Saudi Arabia’s weather. The suggested solution is to design a system that allows the GSM (Global System for Mobile Communication) to communicate with the mobile phone to send the orders from the user. After that, the GSM will interface with the microcontroller to control the devices and implement the action. The system can be used in anywhere of the world if the GSM network is available.