This document discusses the design of a temperature monitoring and controlling system using an Arduino microcontroller. It begins with an introduction to the motivation and objectives of the project, which are to automatically control cooling systems based on measured room temperature. It then discusses the hardware and software requirements, including using an Arduino board, LM35 temperature sensor, LCD display, relay, and connecting wires. The existing systems limitations with using an ATmega8 microcontroller are explained. The proposed system overview is given, which uses an Arduino microcontroller to address the limitations.