Author Topic: joule thief for ir pens.  (Read 4931 times)

Offline sefi

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on: August 14, 2008, 09:39:35 AM
i was trying to make rechargeable ir pens, when i noticed rechargeable are only 1.2 volts probably lower voltage so the can charge from lower voltages... but ir leds (tsal6400) need 1.6 or 1.5 utleast, so 1.2 doesn't do it. ofcurse you can use 2 in series but that takes up more space in the pen and requiers it to be larger and/or thicker...

so i thought that a joule thief can solve the problem, it works like a transformer you can read and see what is it here @ make magazine http://blog.makezine.com/archive/2007/11/make_a_joule_thief_weeken_1.html & herehttp://www.bigclive.com/joule.htm
it can be used to run a blue/white led with even 0.35 volts so it might just do it for the 1.2 volt to 1.6...and u can make really tiny once too :) il check it out and post here....

edit: here is some more detail info. http://www.evilmadscientist.com/article.php/joulethief
« Last Edit: August 14, 2008, 09:49:08 AM by sefi »



Offline Chriss

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Reply #1 on: August 14, 2008, 11:03:27 AM
I use a 1.2v rechargable battery in an IR pen without the use of a resistor and it works absolutely fine.

You should be ok, don't over complicate things!



Offline sefi

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Reply #2 on: August 14, 2008, 04:54:31 PM
well i tried the 1.2V with the tsal6400 and it just dose not light, could there be another reason?! did any1 manage to get the tsal6400 working with a 1.2v?



Offline benpaddlejones

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Reply #3 on: August 15, 2008, 08:18:50 PM
Sefi
1.2v is fine, it is a little underpowered but does not effect results. As Chriss said has the advantage of not needing a resistor so one less solder to mess up.

Are you connecting with correct polarity? or are you expecting it to light up like a normal LED (naked eye cannot see IR light)?

Read: http://www.wiimoteproject.com/ir-pens/electronics-101-sharing-my-mistakes!-***-updated-***/ will answer all your questions and more.

Benpaddlejones :)


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