rgb colour analyzer without a programmming device
TRANSCRIPT
Group MembersT.D. Welagedara 120700P
P.I.L Wickramasuriya 120708X
M. W. A. D. S Wijesuriya 120727E
H. A. R. T Wijesekara 120715P
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)
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.