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RSS >  Hello, question for 3 point LED, For my headset
Neil_B #1 07/08/2007 - 21h27

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I have a headset, it is like this:
Posted Image

I tried using LED Guide but it is kind of confusing for me!

Please, can someone help me to pick 3 LEDs and 3 resistors from American website (www.radioshack.com or any other) ??

They will be powered by this:
Posted Image

I already have copper wire and soldering tools so that is ok.
tristan68 #2 07/08/2007 - 22h29

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Hello Neil.

I've taken a look at radioshack's website, and didn't find a matching led.

They propose one IR led there, but it's only a narrow angle led (definitely doesn't fit for our application, we need a wide angle led).


What you need to find is a wide angle infrared led (usually a Osram or Siemens SFH485P or something equivalent)

Then you should use the Led assembly wizard, there's a link on Freetrack Online main page.

The wizard will provide a small schematic, and resistor values.

If you're still confused, feel free to post here again.

We'll answer ASAP.
Neil_B #3 08/08/2007 - 00h16

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What about this

http://www.besthongkong.com/product_info.php?products_id=105&osCsid=72891a09f03457302760ce5e4e235d37

If it would work then please recommend me resistor
Edited by Neil_B on 08/08/2007 at 00h20.
tristan68 #4 08/08/2007 - 08h58

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Hello Neil.

Yes those leds should work. 60 degrees angle isn't the best you can find , but its already good (at 0.5 radiation strength).

FIY, your should really try to use the Led Wizard, located in the website frontpage ( its your friend <g> ).

resistor values for 3 of those leds (FV=1.2v / IF=20mA) , a 9V battery and a serial type assembly (look at the wizards schematics) are :

270 ohms resistor 5% 0.25w (you only need 1 resistor with a serial type assembly).

btw :
Do you live in HK ???
If you live in US or Canada, i'm sure you can find a shop closer to your location....

cya.
Neil_B #5 08/08/2007 - 10h15

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Hello

No sir I live in USA

I'm sure I can find closer shop but i donot want to go through the hassle

Besides only about $3.57 for 3 IR leds (shipping included)

This resistor work ??

http://www.radioshack.com/product/index.jsp?productId=2062318&cp=&sr=1&origkw=270+ohm&kw=270+ohm&parentPage=search
Edited by Neil_B on 08/08/2007 at 10h20.
tristan68 #6 08/08/2007 - 11h36

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Hello neil

Sure , this resistor works perfectly for the given settings.
It's a bit overkill for the power rating (0.5W) but that doesn't matter.

go for it !

PS :

You should still look if you can order at FARNELL.

They have a great choice of electronics parts, and there's normally no prob to ship to your place.

btw , they have the SFH485P IR led, mucho better  : D

cya
Kestrel #7 08/08/2007 - 13h39

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I'm sure I can find closer shop but i donot want to go through the hassle

Besides only about $3.57 for 3 IR leds (shipping included)



If you're going to 'ship' you might as well get SFH485P leds. It's no more hassle.

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