Alt-BEAM Archive
Message #04352
To: beam@sgiblab.sgi.com
From: Steven Bolt sbolt@xs4all.nl
Date: Tue, 8 Jun 1999 16:32:32 +0200 (CEST)
Subject: [alt-beam] Re: InfaRed
On Tue, 8 Jun 1999, Ben Hitchcock wrote:
> Check out
>
> http://www.xs4all.nl/~sbolt/e-spider_IRbumper.html
>
> It's a bit complicated, but Steven rarely makes things more complicated than
> they need to be, so I guess it needs to be that complex. You could try
> making it a bit simpler, or if you have an old VCR handy you could use the
> IR module in that (like I did!)
There are a couple of arguments in favour of my circuitry.
1) Power consumption is very low - transmitter and receiver
together use just 1.2mA @ 4V, and work fine at less than
1mA @ 3V. Those IR modules tend to require more current
and a higher voltage as well.
2) If you have to buy the parts, those of my circuit are cheaper
and usually easier to find.
3) In my Spider application, the filter and pre-amp do double duty,
receiving sound as well as IR light.
As to simplification:
If your `bot lives in natural light only, there is no need to
filter against interference caused by mains modulated artificial
light. You might try leaving out the Andreyev filter stage. That
saves two transistors and quite a few passives, and probably won't
reduce the detection range all that much. Further simplification is
possible if the detection range can be a lot shorter. In that case
you can try with just the first pre-amp stage, saving another
transistor.
Best,
Steve
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# sbolt@xs4all.nl # Steven Bolt # popular science monthly KIJK #
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