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Author Topic: how to make a circuit of white line detector using IR emitter & detector.  (Read 3866 times)

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Offline rubberTopic starter

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how to make a circuit of 3 set of IR emitter & detector for white line detector?

Offline Strikeskids

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You only need 2 Photoresistors. Use one on one side and the other on the other side. If any of those touches the white line, then turn in that direction. Just connect them up to a microcontroller and program it or, connect each photoresistor in the path to the motor so it slows the motor when it sees white.http://www.radioshack.com/product/index.jsp?productId=2062590
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Offline rubberTopic starter

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You only need 2 Photoresistors. Use one on one side and the other on the other side. If any of those touches the white line, then turn in that direction. Just connect them up to a microcontroller and program it or, connect each photoresistor in the path to the motor so it slows the motor when it sees white.http://www.radioshack.com/product/index.jsp?productId=2062590


thanks for the reply..

sorry. i;m a real beginner to robotics.. do u mind explaining how this work?? thank you very much

Offline rubberTopic starter

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You only need 2 Photoresistors. Use one on one side and the other on the other side. If any of those touches the white line, then turn in that direction. Just connect them up to a microcontroller and program it or, connect each photoresistor in the path to the motor so it slows the motor when it sees white.http://www.radioshack.com/product/index.jsp?productId=2062590



u mean something like this?

if left_photoresistor detects more light than right_photoresistor
then turn robot right

if right_photoresistor detects more light than left_photoresistor
then turn robot left

if right_photoresistor detects about the same as left_photoresistor
then robot goes straight


then how am i going to make the robot goes backward when it going nearer to the white line??

anymore, how the circuit design look like??

sorry for the troubles

Offline SmAsH

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one photocell on each side of the robot when one senses more light (the line) it moves to that side until it does not sense more light on that side. so the robot is always auto-correcting.
look at the attached picture to give an idea of the setup.
Howdy

Offline rubberTopic starter

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but i making a sumo robot.. i don want to get near to the line..

when i get near the line, the robot must move away from the line.

sry that i didnt stat my point clearly.

Offline SmAsH

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ahh my bad, thought you wanted a line follower...
for this one, you want a sort of imaginary box your robot cannot go out of?
if the sides are marked you could do the same thing, have sensors on the corners of your robot
and the when say the left sensor sees the line it will turn right thus moving away from it.
Howdy

Offline rubberTopic starter

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my bad also.. sorry abt that.

which will be better?? line detection using IR emitter & detector or the photoresistor??

i can find the circuit for IR emitter & detector.
http://www.societyofrobots.com/schematics_infraredemitdet.shtml

if i wan 3 sets of this in 1 PC board.. can i jus join 3 of the circuit together??

how do i send the data back to the mircocontroller?


Offline SmAsH

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well for me i would opt for the photo resistor circuit as i have the parts available and its easier to use...
to send data back to the mcu, the mcu has to read a value off the pin, this is done through code.
Howdy

Offline rubberTopic starter

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ohhh.. okay. thank you very much.

Offline rubberTopic starter

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sorry to bother u again.

can help me take a look of the circuit.



http://i671.photobucket.com/albums/vv76/hengsuay_2009/Untitled.jpg
is it correct?

Vin supply by the mircocontroller then the Vout 1,2,3 connect back to the mircocontroller to get the data (1 or 0).

does i need something to convert the data to 1 or 0?

or jus do some programming will do?

« Last Edit: May 28, 2009, 07:34:46 AM by rubber »

Offline SmAsH

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do that is three sensor circuits...
im guessing when there is little light the "vout" goes back through the resistor to "vcc"
when there is light the path through the resistor is harder to it goes through the transistor to "gnd"
the mcu will read the pin in the programming.
Howdy

Offline rubberTopic starter

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so that is correct?

cos i want to have 3 sets of emitter and detector.

something like this

http://www.leang.com/robotics/info/articles/linesen/senspace.gif

Offline galannthegreat

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That would work.
Kurt

Offline SmAsH

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that could work,
but rather just have one or a pair on each corner so it can see if any corner has gone out.
but don't get over excited and put stacks of them on because you may run out of i/o on your mcu.
Howdy

Offline rubberTopic starter

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oh okay. thank you very much.


 


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