Week 5 ( Fyp 1)

Title: Research about the sensor that used in the project

This week i do a research about sensor that i want to use in my project. After i do some research, i've found a couple of sensor that should be suitable for the project i been working for.

Among the proposed sensor for the project:

• IR sensor (passive)
• Area sensor
• Motion sensor

I have selected IR sensor for my project.

An infrared sensor is and electronic device, that emits in order to sense some aspects of the surroundings. An IR sensor can measure the heat of an object as well as detects the motion. These types of sensors measures only infrared radiation, rather than emitting it like the sensor i'm going to use that called Passive IR sensor, its detects a human being or solid object that moving around within approximately 10m from the sensor.

 PIR SENSOR

Most PIR sensors have a 3 pin connection at the side or bottom. One pin will be groud, another will be signal and the last pin will be power. Power ussually up to 5V. Interfacing PIR with microcontroller is very easy and simple. The PIR acts as a digital output so all you need to do is listening for the pin to flip high or low. For PIR sensor can be used to detect presence of human beings in its proximity. The output can be used to control the motion of door. So its also can be used to detect an object such as assingment that been insert into the pigeon hole.

• PIR sensor IC

 In presence of human IR radiations, the sensor detects the radiations and converts it directly to electrical pulses, which is fed to the inverter circuit. The inverter circuit consists of a transistor,which gets into saturation with application of high base current and eventually develops a low collector voltage. Thus the transistor  output is low.

This low inverter output is connected to the microcontroller. Based on the input received by the microcontroller, it controls the counter and produce a counting when a paper (assignment).