Re: Simultaneous IR Object Detection and IR Control?

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Subject Author Date
Re: Simultaneous IR Object Detection and IR Control? Bob Monsen 02-26-2006
Posted by Bob Monsen on February 26, 2006, 2:53 pm
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On Sat, 25 Feb 2006 23:02:02 -0800, redbrickhat wrote:

> I am planning to build a robot that uses a Sharp GP2D120 for IR object
> detection.
> I would also like to control it using a VCR remote control and the Sony
> IR protocol.
>
> Is there any way of doing this without the IR signal from the remote
> control causing the GP2D120 to think it's detected an object?
>
> Any feedback will be appreciated.
>

You should be able to shield the GP2D120 from the IR remote control,
although reflection could be a problem. I wonder if the hood could
be made from something that wouldn't reflect IR? However, I'm also
guessing they are modulated on different frequencies, so you might be
trying to solve a problem that does not exist.

If you simply can't make this happen, for whatever reason, try the
TLP434/RLP434 Easylink Wireless modules. They use RF at 434MHz. They
should work reliably, although they will cost more and take more power.

--
Regards,
Bob Monsen

My life is a simple thing that would interest no one. It is a known
fact that I was born and that is all that is necessary.
Albert Einstein (1879 - 1955)

Posted by Gordon McComb on February 26, 2006, 9:16 pm
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I missed the OP's post, so I'll respond to this one.

Most of the Sharp distance sensors have a very slow modulation compared
to the typical 38-40K modulation of an infrared remote. The differences
in modulations should never cause the output of the distance sensor to
false-trigger the IR remote input.

However, the output of the distance sensors, while a very narrow beam,
is quite bright, so it could conceivably swamp the IR receiver. Merely
mounting the two to avoid this problem should not be hard. The distance
sensor uses a PSD device that would require you to point the IR remote
directly into the aperture of the sensor, in order for any interference
to occur this way. The Sharp distance sensors are made for varied light
environments -- such as brightly lit public restrooms -- so a baffle or
shield shouldn't be necessary.

-- Gordon


Bob Monsen wrote:
>
> On Sat, 25 Feb 2006 23:02:02 -0800, redbrickhat wrote:
>
> > I am planning to build a robot that uses a Sharp GP2D120 for IR object
> > detection.
> > I would also like to control it using a VCR remote control and the Sony
> > IR protocol.
> >
> > Is there any way of doing this without the IR signal from the remote
> > control causing the GP2D120 to think it's detected an object?
> >
> > Any feedback will be appreciated.
> >
>
> You should be able to shield the GP2D120 from the IR remote control,
> although reflection could be a problem. I wonder if the hood could
> be made from something that wouldn't reflect IR? However, I'm also
> guessing they are modulated on different frequencies, so you might be
> trying to solve a problem that does not exist.
>
> If you simply can't make this happen, for whatever reason, try the
> TLP434/RLP434 Easylink Wireless modules. They use RF at 434MHz. They
> should work reliably, although they will cost more and take more power.
>
> --
> Regards,
> Bob Monsen
>
> My life is a simple thing that would interest no one. It is a known
> fact that I was born and that is all that is necessary.
> Albert Einstein (1879 - 1955)

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