The document describes an electronics circuit designed by students to detect deviations from the correct path and warn users. The main components are a NE555 timer IC, LM324N comparator, MC74F08 AND gate, capacitor, potentiometer, buzzer, LEDs, and light dependent resistors. Light sensors with LEDs and LDRs detect the light reflection of different path surfaces to determine deviations. The circuit was built on a breadboard and tested, with the goal of implementing it on a printed circuit board for use in guiding children, the blind, and for vehicle and robotics applications.

1. BY:
SUJEET KUMAR JHA [12009]
MANISH KARN [12035]
AHMED RAJA KHAN [12432]
DEPARTMENT OF ELECTRICAL ENGINEERING
KATHMANDU UNIVERSITY

2.  The main aim of this project to design and implement
the circuit which is used to detect the right path and
warn on deviating towards wrong path.

3. The main components of the electronics circuit
NE555 timer IC
LM324N COMPARATOR
MC74F08 AND gate
CAPACITOR 1000uf
POTS (100K)
RESISTORS
BUZZER
LEDs
LDR

4. NE555timer IC LM324N OP-AMP BUZZER
CAPACITOR
(1000uf)
POTS (100k)
MC74F08 AND
gate

5. LDR1
(Light Sensor)
LED
LDR2
(Light Sensor)

6.  Here the black surface is right path and white surface is
wrong path
 The light sensor module consists of LDRs and LED
 The emitter will throw light on the floor, whose reflection
will then be picked up by the LDR.
 If the path is black, most of the light thrown will be
absorbed and very little light will be received by the
sensors. In this case warning led doesn’t not blink

7. .
•If the path underneath the sensor is white, most of the
light thrown by the emitter will be reflected and received
by the sensor. This will increase the voltage flow to
comparator and the stage at which the voltage cross the
reference voltage and and voltage supplies to led( blinks)
and input for AND gate.

8.  If the right end of the model is deviates towards white
path the led at right most end will blinks.
 If the left end of the model is deviates towards white path
the led at left most end will blinks.
 If the whole model is in wrong path both led's will blink
accompany warning tone of buzzer.
 The tuning of buzzer is obtained by and AND gate.

9. +VCC
GND

10.  Children park, zoo, museum etc.
 Safety measure in vehicles.
 Guide for the blind person.
 Automation and Robotics

11. March April May June July
Proposal and
presentation
Bread board circuit
arrangement
Testing and
Verification
Design in PCB
Modeling of Path
Detector
Assembling, Testing
and presenting of
Path Detector
Work completed
Work Remaining

12. We would like to acknowledge the department of
Electrical and Electronics Engineering for giving us
the golden opportunity to participate in the
engineering project.
We would also like to thank our Project Supervisor
Mr. Subodh Ghimire for his sincere guidance and
suggestions.