Color Sensor

[umairmukati]

Hello Guyz!!
I need to ask you about the task to sense color of three different surfaces by a robot,
please tell me the best way to sense the color specially red, green and yellow.

 

[jkp]

There are several ways to detect color.

1. You could buy a color sensor
2. You could use three LEDs, a red a green and a blue and shine light on the object using one or more LED in different combinations to shine light of different colors. Measure the reflected light using an LDR and given the different readings, decide what color it is.
3. Shine white light on the object and use three LDRs with color filters in front. Use a red, green and blue color filter and use the measured light intensities to decide the color.

 

[umairmukati]

@jkp
The first one is a good idea but at the moment it is to expensive.
I need some explanation on the second method defined by you.
The third one too, i've tried it but failed because color filter is passing both the red and other colors may be it needs monochromatic light to absorb or anything else.
Thanks for the reply.

 

[FreeRideSkier]

Use a webcam and a colour detection module!

 

[umairmukati]

My problem is that I have to use in a robot, and i dont know how to detect it using any interfaces the robot is going to be intelligent.

 

[FreeRideSkier]

If you use a small embedded PC like a FITPC (see photo) and the FlowStone DSP programming language most of it is done for you!

Heres a colour detect project written in FlowStone (This can be opened in FlowStone FREE). Using FlowStone you can make your own EXE file!

 

[House0Fwax]

Have a look at this link, it's along the lines of what jkp was saying.

Cadmium-Sulfide Active Color Object Sensor - Robot Room

 

[jkp]

House0Fwax: Good link. That was exactly what I meant

Using a camera just for detecting color is overkill. Besides, you have to move the camera close enough, so the object fills the entire image. Otherwise, you don't know, what part of the image to look at.

 

[FreeRideSkier]

FYI - The Camera Colour detection automatically detects zones of colour, where you specify the minimum size of a zone and then gives you the XY co-ordinates of each zone in the image! So you don't have to be close!

Watch this video and you'll see how a web cam tracks the red target on a Biped, then fires a laser
YouTube - Brat vs Alien Arm.avi