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Why this led circuit doesn`t work? Answered

Hi everyone, you see build this infrared-led circuit for a school project (am 16 and not in america
so sorry for missespells, like that, pretty sure that missespell is not the word)
This are the parts:
3v Led
3v Ir receiver (with 3pins)
Jumper wires
Can please tell me why doesn`t work???
What i miss??
Above some pictures.

13 Replies

cyberpagemanBest Answer (author)2009-11-03

Good job of showing the circuit!   I don't understand it though.  It looks to me as though you have the switch wired across the battery terminals, so that when you push it, it shorts the battery out.  Take it out for now.

I can't tell if you have the LED and the receiver wired with the correct polarity.  Also, you need a resistor to protect the LED and detector.  Check out the Instructable, "IR Detector." (https://www.instructables.com/id/IR-Detector/)

You show a ground wire on the detector.  I don't think this is wired correctly.  It would normally go to the negative terminal of the battery.  Give us the part number of the detector, and one of us will look up the wiring.

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  Hi Ik0,

You've been getting good answers. Notice people asking for more information about the detector? Try to tell us.

I looked up your member information and see you are 18 and from Argentina. You write English well.

I also looked up three wire IR detectors. I don't know which pin is which on your detector, but one wire goes to 0 v (the ground), one to the + 3 v, and the other would go to the LED (which is connected to ground). You should put a resistor between the+3 v and the detector. The resistor should be 200-500 ohms.

The IR detector I looked up had a 6v maximum. If yours is similar, It will be safer if you replace the 9v battery with 3 v (two 1.5 v in series) so you don't need a voltage regulator. It might also be easier for you if you replaced your 3 wire IR detector with a two-wire IR photoresistor, like that used in the IR-Detector instructable. Then you could keep the 9v battery.

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Ik0 (author)2009-11-05

Almost done!

Thanks for that circuit, im gonna try it at school later, amnd telleing you how it went.
You see, my first atemp have serius problems, starting with the power
supply, and the grund pin of the detector (wasn`t connected to anything).

And the ir receiver certanly requieres a ir modulated signal, cause i gor it from
a cd portable player circuit bord thart has it, i also have the remote that sends
the adecuate ir signal. But that signal needs to be amplified in order to
connect a terminal of the battery???

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cyberpageman (author)Ik02009-11-05

 Don't know if the signal needs to be amplified.  Bring the remote up to the detector to "amplify" it.  Let us know how everything works out.

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Ik0 (author)2009-11-04

Thanks cyberpageman for answer. well.
 my ir receiver doesn`t have any thing that reveals it model, mark series or
anything. But i miss to add that i already know which pin is 3v, Grnd and out.
The middle pin is 3v, the left one is out and the right one is grnd.

what else info will be required??
o, right, and i can get some resistor out of a broken radio of a friend, as well
some inductors and capacitors.... but for know this.


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cyberpageman (author)Ik02009-11-04

Maybe member Seandogue is right, the IR detector will not work if it requires a modulated IR signal.  However, here is a circuit like that of the IR-Detector instructable..    The resistor should be 200 to 500 ohms.  If you don't have a resistor, you can make one.  See  https://www.instructables.com/id/Make-a-Pencils-Lead-Potentiometer-Experimentatio/

What are you using for an IR light source?  This circuit may work with a television controller, but I am not sure.

Note the battery is 3v.  9 v is probably too much, as Zerogx says.

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Ik0 (author)2009-11-03

Hey, thanks for the answers.
I kind a need to complete this for a school project and this (the
parts that i show) well is the only things that i have, you see, here it`s
hard to get the parts that would make it easyer. and i also have some issues

trying to understand the concept ground with my ir receiver isnt`s suppose
to be a dump for the charge?

Anyway, it`s possible to build an ir detector like: www.instructables.com/id/IR-Detector/ with the parts that i have?? i try but kind a ned advices.

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cyberpageman (author)Ik02009-11-03

 Yes, it's possible to build an ir detector similar to the instructable one, but you MUST TELL THE MAKE AND MODEL NUMBER OF THE IR RECEIVER.  If you can't read it off the detector, let us know.  You will also need a resistor, though you can make one out of a pencil lead if you can't get one.

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seandogue (author)2009-11-03

IR transceivers usually use a modulated carrier and are not suitable for DC operation.

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gmxx (author)2009-11-03

 to begin with, you have power issues.

your battery is being shorted with that switch. you might need to put jumpers over the splits on the power rails... i know the breadboards i use require you to do this.


judging from the wiring you have on the ir reciever, the ground doesnt go back to anything, 3v power is going to the output port, and 3v line is connected to the negative side of the led. 

switch the wiring so that 3v is connected to positive power, and output goes to the led... and the battery probably is too much, leds and the note on the ir sensor tell me it is a 3v system. you're running it at 9v

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steveastrouk (author)2009-11-03

And a circuit diagram please.


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Re-design (author)2009-11-03

I've never used an Ir receiver. 
Where is the data sheet for the one you bought. 
Chip number please?

Do they act as a phototransistor?

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memyselfand1 (author)2009-11-03

OK, it might help if you could annotate that picture, by dragging across the elements. What have you got going into the IR reciever?

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