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)
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
7.
8.
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
12.
13.
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
15.
16.
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.