EN 2012 & EN 2022Group project

Group 24

Group MembersT.D. Welagedara 120700P

P.I.L Wickramasuriya 120708X

M. W. A. D. S Wijesuriya 120727E

H. A. R. T Wijesekara 120715P

Contents1. Introduction

2. Design

3. Components

IntroductionProject: RGB Colour Analyser

Objective: Measure and display the amount of red, green and blue in a given colour sample

Only use basic analog and digital electronic components (without programmable devices)

DesignDetector

ADC

Binary to BCD converter

Display

DetectorDetects the amount of red, green or blue in the sample

Red, green and blue LEDs and LDRs

Points the LED at the sample and measure the amount of reflected light using the LDR

Black cup to reduce the interference of outside light

Variable resistors to calibrate each sensor with respect to a reference red, green, blue surface

Analog to Digital Converter (ADC)Use the ADC 0804 chip as the converter

Input : A voltage proportional to the amount of the specific colour in the sample

Output : A binary value of the input signal from 0 to 100

Binary to BCD ConverterConvert the 8-bit output of the ADC to three BCD values

Need: To feed the display unit

Use three DM74185 chips connected as per the following circuit diagram to achieve the task

Control SwitchesConsists of 3 push buttons to activate each of the green, red, blue sensors

While a push button is being pressed, the device will display the percentile content of the corresponding colour in the sample

DisplayDisplays the final output - the amount of specific colour in the sample

Use three 7 segment displays

CMOS 4511 driver chips used as BCD decoders

Pull up resistors used for TTL to CMOS interfacing

ComponentsLEDs - Ultra Bright

LDRs

ADC0804 - No external clock required

DM74185

4511 decoders

7 segment display – common cathode

2N3904 transistor

Resistors, capacitors, diodes and other electronic devices (7805 regulator, 555 timer)

Results obtainedDue to the interference from the outside light , there were some variations in the calculations

Shows considerably accurate results in the testing.

Intended results were obtained.

Thank you!