The motivation behind the project:

This object detection sensor is specially designed to provide security from an unauthorized entry of an object or a body. In your absence, it will not let anyone enter your place unless you allowed him. If someone tries to enter, this sensor will detect it and sound an alarm that will alert your security system and you will be safe from any threat.

Working:

In this device, the major component is a PIR sensor that typically operates on 5V and this 5V is provided by voltage regulator IC LM7805. The purpose of using the resistor is to limit the current, the relay is used to control any load, the buzzer is used to sound an alarm in case of sensing any object.

The first step is to provide the power supply to the device through the battery. Initially, the PIR sensor will give the output pin as low but as it will observe any presence of infrared rays, transistor BC547 will become active and it will start conducting current, this will activate the relay and buzzer connected to it and the load will start working. The load could be any fan or bulb. The purpose of using the diode is to provide protection to the relay in case of reverse flow of current.

Using an online platform Inventhub, I have made my project online where I have uploaded all my design files to get connected with my manufacturer. He will export my BOM and release file and will fabricate my PCB without any error.