Line following Robot

[ashesv14]

I got a project of building a line following robot. The robot has to follow a track with one side being White Background with a blue line and the other black background with a blue line.


1) Firstly, How is possible to sense the blue line with blackground.

2) I want to use three sensors, the circuit diagram attached to this post use 2. how can this circuit diagram can be modified to include three sensors and a the component H bridge in the circuit.

Thanks for the help

 

[jpanhalt]

How much do you know about the dye/pigment used for the blue line. A lot of blues are fluorescent. That might make it easy.

Failing that, you will need to know whether simple intensity of the reflected light will distinguish the blue from the black. A lot of what we perceive as color really doesn't require color discrimination to detect.

Failing both of those approaches, then get a blue light about the same color as the line and use that for illumination. The blue should reflect it more than the black, so it will appear brighter.

Now, anticipating your next question, how does one tell the blue line on a white background? You can also have a white light and filters to help distinguish the blue with both a white background and black background.

Here is a link to color subtraction to help you understand: http://www.physicsclassroom.com/class/light/u12l2e.cfm

John

 

[(*steve*)]

get a blue light about the same color as the line and use that for illumination. The blue should reflect it more than the black, so it will appear brighter.

Or a yellow one so it appears darker.

 

[jpanhalt]

I was assuming "black" absorbed all colors. Blue (reflected) absorbs yellow too.

My swag is that the teacher added this little twist to try the impossible -- make the students integrate what they learned about colors with what they are doing now.

Now, if it were me, I would use two or three LED's -- blue, red, and/or maybe, white. My guess is that a third, "reference color" will not be needed.

John