Subject:
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Re: IR output on HB
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Tue, 5 Aug 1997 20:20:25 GMT
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Original-From:
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Fred G. Martin <fredm@media.mit%AntiSpam%.edu>
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Viewed:
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1335 times
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No, don't use a transistor! The HB's IR out already has one.
But the parallel-with-a-separate-resistor-for-each method is correct.
-Fred
In your message you said:
>
> Like so:
> +5v
> |
> +---+---+---+---+---+
> | | | | | |
> \ \ \ \ \ \
> / R / R / R / R / R / R
> \ 1 \ 2 \ 3 \ 4 \ 5 \ 6
> / / / / / /
> -- -- -- -- -- --
> \/ \/ \/ \/ \/ \/
> -- -- -- -- -- --
> HB + | | | | | |
> \ | | | | | |
> / 1K +----+----+---+---+---+---+
> \ |
> | |/
> +---| 2N2222 NPN transistor
> |\
> |
> Gnd
>
> Depending on the current you want through the LEDs you should
> pick R1 - R6 to be 270 - 470 ohms. To compute the current use
> ohms law, taking into account that the voltage drop across the
> 2n2222 and the Led's will be about 1.5 volts. (ie 5 - 1.5 = 3.5v
> so for 10mA a 330ohm resistor could be used).
>
>
> Phethsavong Prachith wrote:
> >
> > Hi, I'm trying to get the ir output on the handy board to power more
> > than 4 LEDs (need to power 6), anything beyond that the ir signals
> > become drastically weak. I have these LEDs wired serially. I'm not too
> > familiar with electronics, so is it possible to amplify the signals the
> > ir output generates?. If so how?
> >
> > + - + -
> > Grnd <---|-----O------LED-----LED----
> > | - + - + - + |
> > <---|------LED----LED-----LED--
> >
> > O is a 10k pot
> > 3-4 LEDs work great but anymore just kills the signals.
> >
> > thanks,
> > phet
>
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Message is in Reply To:
 | | Re: IR output on HB
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| Run them in parallel, use a transistor. Like so: +5v | +---+---+---+---+---+ | | | | | | \ \ \ \ \ \ / R / R / R / R / R / R \ 1 \ 2 \ 3 \ 4 \ 5 \ 6 / / / / / / -- -- -- -- -- -- \/ \/ \/ \/ \/ \/ -- -- -- -- -- -- HB + | | | | | | \ | | | | | | / (...) (27 years ago, 5-Aug-97, to lugnet.robotics.handyboard)
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