This is a project of automatic on off proximity switch using 4017 IC. This project can be used at the entrance door of any room, garage, washroom etc to automatically switch on the lamp or lights of the room when you enter inside and switch off when you go outside of the door.
The circuit contains two
sections the first section is a light dark sensor circuit built with two transistors. And the second section is built with a CD 4017 CMOS decade counter IC that is wired as a toggle switch here. The LED1 provides continuous light on the surface of the LDR.
The circuit requires a proper fitting to work smoothly, for this purpose you have to use two boxes and place them in front of each other at both side of the door. Fit LED 1 with its 390 ohms current limiting resistor in a box and the remaining circuit in another box and make a hole in the box so the LDR will receive the light of the LED 1 continuously on its surface. Now if any person or object will pass through that door the LED beam will be interrupted and the relay switch will become activated, and switch on any electrical appliance connected with it. Same as when you pass again through that door the LED beam will interrupt again and the relay switch will become deactivated and switch off any appliance connected to it.