Subject:
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Re: running 2 IR
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Wed, 9 Apr 1997 19:41:45 GMT
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Original-From:
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Jeffrey Strauss Morehead <morehead@eceSTOPSPAM.utexas.edu>
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Viewed:
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1442 times
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If the IR LEDs both add up to a current requirement of 800ma (the spec on
the ztx614) then yes you should be able to. You may want to add a resistor
to supply that assures you don't get more than 800ma from supply (if that
is Imax for those LEDs).
However, Victor's original question was to run two or three leds *one* at
a time. The only way I know of is to use two or more separate digital
outputs. You could tie the leds all up in parallel on the IR output of the
HB and tie the grounds to each one through separate transistors driven by
separate outputs.
jm
On Wed, 9 Apr 1997, Sriram Tirunellayi wrote:
> >
>
> Can we not tie two IR LED's in parallel and plug into the IR port on
> the HB. ?
>
> > What you can do is just like the schematic for the built-in IR emitter
> > circuit. You need to either software generate your wave or do it like the
> > schematic. If software generated, this output would come from a output
> > port on the HC11 to a transistor base (a bipolar capable of handling the
> > current requirements(collector current spec Ic) of the IR emitter. The
> > emitter of the bipolar darlington (as in the schematic) would be connected
> > to ground and the collector could be tied to one side of the emitter. The
> > other side of the emitter would be tied high through a resitor that sets
> > the current necessary to drive it. The transistor acts as a switch to
> > ground driven by the HC11.
> >
> > Now, if you wanted three driven separately, you could use three output
> > lines, or you could drive some logic to switch between them for you and
> > have even more emitters if you wanted and use only three or four outputs
> > total.
> >
> > jm
> >
> > On Sun, 6 Apr 1997, MAR ERICSON wrote:
> >
> > > You mean IR "emitters"? (IR LED)
> > > If i understand you correctly, you wish to source current with the
> > > digital outputs. The digouts are from the HC11. There can't source enough
> > > current to light IR LED's.
> > >
> > > -----------
> > > ericson mar
> > > Master of Engineering Candidate
> > > Project: Mobile Robotics
> > > mar@cooper.edu
> > > (212)353-4356
> > >
> > > Department of Mechanical Engineering
> > > The Cooper Union for the Advancement of Science and Art
> > > -------------------------------------------------------
> > >
> > > On Sun, 6 Apr 1997, victor w clark wrote:
> > >
> > > > I want to be able to run 2 or 3 IR xmitters from the single output on the
> > > > HB with no additional hardware.
> > > >
> > > > Is there any problem with hooking two or 3 IR transmitters to the ground
> > > > of the IR output and running the +5v from digital outputs. Then switch
> > > > thru each one using the digital output. Only having one active at any
> > > > given moment.
> > >
> > >
> > >
> >
> >
>
>
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