Design and construction of an automatic shutdown device using programmable PIC16F844A micro-controller

Abstract

This study presents a design for the construction of an automatic programmed audio shut-off device. Theproposed system employs the use of a programmed timer consisting of time ranges that can be selected based on the user’s choice. The power source for the device is the direct current (AC)AC supply which is rectified and stepped-down to supply the discrete components of the device. Also, the shut-down is activated by the instruction from the programmed PIC16F844A micro-controller which in turn is used to control the relay action. The idea of this research was aimed at improving the reliability of home-based appliances, providing a well secured alternative for emergencies at residential, commercial and recreational centres and of providing an easy way of switching and controlling devices when the user is unavailable or incapacitated to do so. The desined circuit offers flexibility of repair, avoidance of redundant components and ease of utility by users. Relevant components employed ranges from 220/12V step-down transformer, rectifier, 12 V relay and push buttons for initiating the control and accessing the features incorporated in the design. At the end of the project the device was tested and found to be capable of initiating the intended shut-down in record time as designed. With full optimism, the proper application of this research work will save alot in our community and if more researches are directed towards this area of electrical engineering, security of lives and properties would be greatly improved. This concept is found to be incorporated in the latest design of the i-stereo speaker unit, which shuts down automatically if there is no audio signal detected for few minutes