Current Journal of Applied Science and Technology

The objective of this research is to design a “Microcomputer Based Multipoint Time Operated Power Switching System” (with overload protection). The system is made up of eight relays that can be controlled independently through the parallel port of a computer using visual basic software. It is a time operate electrical appliance controlling system and is a reliable circuit that takes over the task of switching the electrical devices ON/OFF with respect to time. Once is set and device activated, the device remain on till the set time elapses. With the aid of software devices on/off indicate the set time perimeter (hr. Min: sec) and the corresponding real time clock are displayed at the front of the panel. It can be time event, intervals of time and can definitely control AC appliances, it will trigger a relay when it has timed down. The system makes use of a real time check built around the computer system clock and keeps track of the time. When this time is equals to the programmed off time of a device, then the corresponding relay for the devices is switched off. The switch time can be edited using the peripherals devices like the keyboard and mouse.