Paper Title
Design and Implementation of Microcontroller based Automatic Power Changeover Switch between Mains Power Supply & Auxiliary Power Supply

It is disheartening that Nigeria with her teeming population of over 160 million has a total installed capacity of less than 4000 megawatts, and as a result of that; most households and businesses have resorted to private fossil fuel generating sets to power their homes and businesses. In addition; there are processes that are not suppose to be interrupted because of their importance, for instance; surgery operation in hospitals, robotic activities in manufacturing and production process, bank activities in banking sector, among others. This paper presents the Design and Implementation of Microcontroller Based Automatic Power Changeover Switch between Mains Power Supply & Auxiliary Power Supply (Generator). The Automatic change over system guarantees reliable and seamless power when outage occurs. It automatically switches over to the auxiliary power supply when mains power supply fails thus; providing the highest protection for our equipment and home appliances, continuous power supply for; surgical operations, manufacturing process, production line, banking activities, and lot more. The importance of the designed system cannot be over-emphasized when one put into consideration the; endemic, epidemic, pandemic, and epileptic power supply system in Nigeria. The designed system has two main sections; the hardware section and the software section. To design the hardware section, the following components were connected together in the right manner; the AT89c51 microcontroller, actuators, Operational Amplifier, Seven Segment Display, etc. The microcontroller is used to store all the assembly language program of the system, while the Seven Segment Display is used to display the output state of the system at any point in time. For the software section, the Top universal programmer was used to transfer the machine code (software) of the system to the microcontroller. Other components that made up the system were interfaced to the microcontroller to achieve the desired system. The prototype of the automatic power changeover switch worked according to the specification and quite satisfactorily. Keyword- Microcontroller, Automatic Change Over, Actuator, Seven Segment Display, Operational Amplifier (Op-Amp).