Instructables

Color Detection Using RGB LED

Picture of Color Detection Using RGB LED
Have you ever wanted an automated way to detect the color of an object? By shining light of a certain color on the object and looking at how much light is reflected back, you can tell what color the object is. For example, if you shine a red light on a red object, that light will be reflected back. If you shine a blue light on a red object, the object will absorb some of that light and less of it will be reflected back.



 
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Step 1: Parts Needed

Picture of Parts Needed
I used a PIC 16F887 Microcontroller, but almost any with a pulse-width-modulation capability will work.

1 RGB LED
1 Microcontroller
1 Standard red LED
1 1k ohm resistor
1 Photoresistor (changes resistance depending on the amount of light shone on it)
Some wires

I only need the microcontroller and RGB LED to have a wide range of color detectors, but if you only want a circuit that detects one color, you don't need a microcontroller - you only need a bright LED of the color you want to detect. The standard red LED is the "indicator LED" - it lights up when the right color is detected.

Step 2: Build the Circuit

The schematic is rather simple, and in general form, is shown below. The RGB LED is externally powered by a PWM signal.

I put electrical tape around the photoresistor so ambient light doesn't get in - only the light directly above it will be detected.

fzolkifli20 days ago

can u make it on arduino uno?

amikoamoo2 months ago

What it costs? my e-mail is amikopertenava@gmail.com

kvendhan b7 months ago
really nice
svaladez19 months ago
Hi, may I have full scheme for you color sensor...
My e-mail is cristysonia@yahoo.com
UNGUREANU10 months ago
hi..could you send me the schematic for this project..my email is razvan_spyd3r@yahoo.com..thank you
mtaqmilly1 year ago
Can i have your full scheme for color detection...
My email mtaqmilly@gmail.com
aimamo1 year ago
awsome!
Can i have your full scheme for color detection...
My email : dbestworld90@gmail.com.
thank you..
macxfady1 year ago

Thks for the info..recently im doing the colour detection circuit
plz send me a schematic diagrams of full project.
my email: macxfady@gmail.com
thank you
ongjq2 years ago
Thks for the info..recently im doing the colour detection circuit..can i have a copy of your schematic diagrams..this is my mail: ongjiaqing@hotmail.com..thks a lot..
Plz send me full scheme for color detection...
My email id is: sraikar_naveen@yahoo.com
setu3 years ago
its great...but u have to change every time the led light to sense the color ...actually i want to design a color sensor for my project which can sense RGB colors continuously without any need of changing led light every time...if there is a way plz tell me....my id : sunlitesetu@gmail.com
vojkann3 years ago
hi.... can you send me full scheme for color detection.. :D
It would be good if you send it to me... :D
here is my email: vojkann@gmail.com
qz90903 years ago
This is a pretty COOL Instructable and I would like to do the something similar with a project of mine but I am a little confused. 1) Can you provide some more technical details, for example, part numbers and sources to get the parts? 2) Also, you said the RBG LED is powered by an external PWM signal, but in your schematic, it looks like it is connected to a 5V power supply. Thanks.
jsnng004 years ago
Hi there? can u send me 1

Color Detection Using RGB LED diagram for me?

i need for my study.. grateful 
jun_sheng00@hotmail.com
Do you think you could do this with a white LED and 3 photoresistors, one with a red filter, one green filter and one blue filter? Then you could tell if something was say, yellow, because the indicator LEDs on the green and red photoresistors would trigger, or something purple, because the blue and red indicators would trigger, etc. Thoughts?
that would work, but the output of white leds isn't that linear. It might be easier to just cycle through the lighting colours quickly, and figure it out from there.
I think i would work better if you used different colored LEDs and just 1 photoresistor instead, it seems more reliable then using filters.
Possibly, but you need to reflect quite a lot of light off the object to make this work, but this project already requires that so yeah, a really bright white led and 3 filtered photoresistors would be gud hope i helped
draxos4 years ago
Very Nice Work Kyri.... Keep it up ..
Skater_j104 years ago
Great Idea! I to was wondering how to simplify color detection, and now all the hard work has been done already, a big thank you to Kyri. I will try to use this concept on my next bot!
dark sponge4 years ago
But if you hold up a shiny object, like a white lego or a mirror, wouldn't it say it found the color it was trying to detect?
praetorious4 years ago
Hey Nice work! I've done this before and have a few tips. You need to use a filter of some sort to remove IR radiation. I salvaged one from a camera. This will improve the detection. Also, I added white LEDs to illuminate the object so that the reflected light is then detected.
A guy over at a website called robotroom has done this. On my web page it's.
http://amitnv.solarbotics.net/Colour_Vision.htm
Still under construction and missing a few things...
Kyri (author)  praetorious4 years ago
Oooh, cool, thanks for the tips! Nice site, I like how you put a lot of the theory behind why this works (I only understand it so-so, mostly I just built the circuit, tried it, and to my surprise it worked!)
Thank-you. I honestly like what you have come up with. It's simplicity is a very desirable aspect of the design.
praetorious4 years ago
Oh yeah, you can also use the RGB LED itself to detect the light instead of the photoresitor. LEDs have a spectral response which is the same as the frequency of light they emit
nf1194 years ago
wow, when i was watching the video i was wondering if you were from cmu for some reason, then i looked at your page, go ece! lolz
jeff-o4 years ago
Awesome! I was wondering how this might be accomplished - now I know. Thanks!
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