Project title:-

Color Sensor

Department of Electronic Engineering

Faculty of Engineering & Technology

International Islamic University, Islamabad.

Color sensor

Outline:-

Objectives

Color theory

System introduction

Optical system

Electronic system

Application

Objectives:-

To design a sensor which can detect light of diff color and able differentiate

between them.

Color theory:-

Primary and secondary colors:

Primary colors:-

Primary colors are sets of colors that can be combined to make a useful range of

colors. For human applications, 3 primary colors are usually use, since human

color vision is trichromatic, primary colors subdivide into Primary Color Additive

Subtractive .

Secondary color:-

A secondary color is a color made by mixing two primary colors.

Subdivision of primary color:-

Primary colors dividein 2 parts.

Additive primary:-

An additive color model involves light emitted directly from a source or illuminant

of some sort Combining one of these additive primary colors with another in

equal amounts produces the additive secondary colors Combining all three

primary lights (colors) in equal intensities produces white.

RGB Color Modeling:-

Primary color

Additive Subtractive

An additive color model in which RED, GREEN, and BLUE light is added together in

various ways to reproduce a broad array of colors Used in sensing representation,

and display of images in electronic systems, such as televisions and computers.

Subtractive primary:-

A subtractive color is based on absorption phenomenon. Each color is caused by

subtracting that is, absorbing some wavelengths of light and reflecting the others.

This model explains the mixing of paints, dyes, inks, and natural colorants to

create a full range of colors.

System introduction:- (Block Diagram)

Light rays from a color light source fall on the optical components of the Color

Sensor. The optical components filter and focus the rays on the optical sensors.

The output of the sensors is processed by the electronic circuitry and the

corresponding color output is obtained. Photodiode is used in optical component.

Color light

source Optical

Component Sensor

Signal

Conditionin

g

Output

Electronic System :-

LM324 IC:- (Comparator)

LM324 comparator can compare 4 pairs of voltages. For a single IR sensor, only

one channel is enough. Here we would be using pin 1,2 and 3 for our sensor.

Lm324 is a 14pin IC consisting of four independent operational amplifiers (op-

amps) compensated in a single package. Op-amps are high gain electronic voltage

amplifier with differential input and, usually, a single-ended output. The output

voltage is many times higher than the voltage difference between input terminals

of an op-amp, these op-amps are operated by a single power supply LM324 and

need for a dual supply is eliminated. They can be used as amplifiers, comparators,

oscillators, rectifiers etc. The conventional op-amp applications can be more

easily implemented with LM324.

Input voltage at pin2 > input voltage at pin3 ; Output1=> logic 0

Input voltage at pin2 < input voltage at pin3 ; Output1=> logic 1

Connect the output of our sensor(photo diode) circuit to pin2 & connect

potentiometer to pin 3of this IC. When the output coming from sensor is high

then final o/p is 0.but when the output coming from sensor is low then final

output is 1 , We also uses phototransistor, resistors and potentiometer for getting

output we placed LED’s.

Applications:-

It can perform sorting operations Avoids separation of medicines in

pharmaceutical industries. Brick sorter in the recycling industry, sorting plastic by

color for recycling purposes. For example all the green 7-Up bottles down one

conveyor, line follower reborts is also one of its application and so many apps.