This document describes a group project to build an RGB color analyzer circuit. The circuit uses LEDs and LDRs to detect the amount of red, green, and blue in a color sample. An ADC converts the sensor output to a binary value representing the color percentage. Binary values are converted to BCD for display on 7-segment displays. The circuit allows selecting each color sensor using push buttons and displays the corresponding color percentage. Components used include LEDs, LDRs, ADC, BCD converters, displays, transistors, and other basic electronic devices. Testing showed accurate results when calibrating for interference from outside light.

1. EN 2012 & EN 2022
Group project
Group 24

2. Group Members
T.D. Welagedara 120700P
P.I.L Wickramasuriya 120708X
M. W. A. D. S Wijesuriya 120727E
H. A. R. T Wijesekara 120715P

3. Contents
1. Introduction
2. Design
3. Components

4. Introduction
Project: 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)

5. Design
Detector
ADC
Binary to BCD
converter
Display

6. Detector
Detects 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

9. 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

10. Binary to BCD Converter
Convert 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

11. Control Switches
Consists 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

14. Display
Displays 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

17. Components
LEDs - 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)

18. Results obtained
Due 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.

19. Thank you!