help with line following sensor circuit

tshuck

Joined Oct 18, 2012
3,534
See here.

You two should get together and tackle this project together!;)

Since this is homework....what is it you think you need? How are you going to approach the problem?
And if I need a comparator?
Do you need to compare things? That is what a comparator does....
 

Thread Starter

Maniaks

Joined Feb 10, 2014
8
I need to detect the lines colour. I am wondering if that mentioned circuit will work. I'm thinking of only using one sensor to exclude the comparator, but what will be the disadvantages of this?
 

R!f@@

Joined Apr 2, 2009
9,826
I'm thinking of only using one sensor to exclude the comparator, but what will be the disadvantages of this?
Robot following line .........:D
Suddenly forgets where the line is....robot goes ":confused:"!

You might yell out. :eek:
"Get back to the road you little bugger". :mad:
 

Thread Starter

Maniaks

Joined Feb 10, 2014
8
Yes. Well I can get a microcontroller, I just wanted to do it as simple as possible. The background doesn't matter.
 

Thread Starter

Maniaks

Joined Feb 10, 2014
8
Ok, making headway. One question, will the above circuit be compatible with 9V battery? And coudl someone help me understand the circuit. I'm having trouble understanding the RED LED. why does it light up (if RGB replaced with blue LED) when blue light comes on. If the circuit has a current shouldn't it be lighted up like the blue LED all the time?
 

R!f@@

Joined Apr 2, 2009
9,826
If you want to talk about the circuit, post it first.

Not a link to somewhere.
Post the circuit that you want to make.
 

R!f@@

Joined Apr 2, 2009
9,826
Ok!
Simple fact. To detect a certain spectrum you need to apply filter to the detector which will block all the color except the color you want.

Unless you make a circuit that can detect a certain color. Which includes comparator and other circuits too
 

R!f@@

Joined Apr 2, 2009
9,826
IR filters, color filters.
Do a google search and you will see plenty.

The filter needs to be placed in front of the detector. Then the detector will produce a signal when that light is available. The detector can detect a broad spectrum but the filter blocks all but a certain spectrum to fall in the detector.

But for this I think a LDR will suffice as photo detectors detect Infra Red. Which eyes can't see.

May be some other member can highlight this.
 

Thread Starter

Maniaks

Joined Feb 10, 2014
8
ok, thanks. But what about the 9V(can it handle that?), and can you give a little information on why the indicator LED lights up, if the correct spectrum is recieved by the photoresistor. What I see is that the current passes trough the photoresistor(which initial resistanc evalue is quite large, meaning no big voltage on the "branches"), but if the light is absorbed the resitance lowers, and light the indicators lights up. What I don't get is why does the RGB(or any single colour LED) lights up before hand. Do i need to apply a separate voltage to it?
 

R!f@@

Joined Apr 2, 2009
9,826
Well !
Don't you get it. That is the reason for so many circuits and comparators.

You have to make it simple. Then sometimes simple things don't work and that is what you get if you wire a LED in series with a photo resistor.
I believe one or other will end up in smoke sooner or later.

A specific color line following robot cannot be made with just passive components.
 
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