A NEW CONCEPT OF LIE DETECTOR

Abstract

This project provides a critical overview of the scientific status of lie detector test using microcontroller. The test consists of simultaneously monitoring blood pressure of the person. Instruments for recording changes in blood pressure has been used with considerable effectiveness in criminal and personnel investigations for the purpose of determining whether the person being tested is telling the truth regarding the matter under investigation. The theory underlying a lie detector test is that lying is stressful, and that this stress can be measured when monitoring blood pressure of the person with the help of the sensor and the signal is transferred to the microcontroller. Then the microcontroller switches ON the either Red or Green LED Light through driver according to the input data. If the Green LED glows that means the person tells only the truth otherwise Red LED will be glow that means he/she tell lies to the investigator. As suspects are questioned, the device checks which LED light to be glow whether the person tells truth or not. However, this project is very useful to both the investigator and other departments. In this project the PIC16F877 microcontroller is used and the programs are written in assembly language.

Existing System

Proposed System

Architecture

BLOCK DIAGRAM