Red Line Follower

I wish to build a line follower, which can follow red line on white background, i tried with IR sensors but it can't distinguish red from white...

Which sensor should i use...???

-> white LED with photo-transistor
-> white LED with LDR
-> red LED with photo-transistor
-> red with LDR
-> IR with LDR
-> Any other

Please help...

forgot to mention, i tried IR with photo-transistor (photo-diode).

You want a phototransistor sensitive to the mid/upper end of the spectrum and use something like a green LED. Green reflected of red wil be pretty dark whilst it should be bright reflected off white. A RED Led will be bright off both. LDRs are probably a bit slow for line following.

GREEN LED with photo-transistor . :slight_smile:
but have a look look at the specs of the phototransistor :wink:

-Thanks Groove :slight_smile: :wink:

@newbie: how are you going to differentiate a red line with a red LED (unless it is on a green background?)

:-[ Oops got the conccept worng :-X

@newbie: how are you going to differentiate a red line with a red LED (unless it is on a green background?)

@newbie: how are you going to differentiate a red line with a red LED (unless it is on a green background?)

i replied

Oops got the conccept worng

i went wrong with the part as to how a item gets it colour ( absorbs the other colours and reflects it's own )
i took it the other way !

hey thanxs a lot guys...

i'll build it n chk d result...

Why a red line? Why not black ?

Because it is to be used to recreate the Highland regiment's exploits at the Battle of Balaklava?

Groove ;D

But how many other on this board will understand that?

Also what if the line is thick and not thin.