LED for line sensor

[McFire]

Hi,
I want to make a line detector with a Cds Cell and a LED.
Now my question is what kind of an LED should I use.

#1
Diffused or clear

#2
Wide or narrow viewing angle

#3
Red, Green, Blue or Orange

This is kinda of subject but:
Can I build a fully functional sumo bot with the $50 microcontroller

Thanks in advance for any suggestions.

[SmAsH]

#1. generally clear if you want it to be brighter.
#2. well, if you want it to be more focused go for narrow, but both can be fine.
#3. im not too sure but blue and green tend to be good choices.
#4. hell yes, the arduino's use a chip that is practically the same as the $50 robot.
the $50 robot tutorial only shows how to get like 10 I/O out of the board...
the atmega8 has 20 I/O available for use, 17 excluding the programming header.

[Finnik]

The color of the LED you need to take depends on the colour of the line you're following. If it's a black line on a white surface, any color will suffice. If the line and surface are other colours that black and white, look up which colour absorbs what colour of light. White reflects all colours of light, black absorbs all, but e.g. blue absorbs all colours except for blue. Pick a colour which allows you to detect the difference between the colour of the line and that of the surface it's on.

[McFire]

Ok,
I think I'll try it with Orange and if that doesn't work I'll use Blue.
Thanks for the replies.

[Soeren]

Hi,

Using an RGB LED, you can find the best color by scanning the actual line vs. background color and make it select the one giving the largest contrast.
Otherwise, a (warm)white LED is probably the best all round color.