Alt-BEAM Archive
Message #07290
To: beam@sgiblab.sgi.com
From: Evan Dudzik evandude@yahoo.com
Date: Tue, 2 Nov 1999 12:56:47 -0800 (PST)
Subject: [alt-beam] directional antenna?
does anyone have any ideas on how to build a
unidirectional antenna? this would be great for homing
in on RF signals... otherwise, i have another idea.
take three antennas, and place one in the center of
the bot... take the next two and place them at the
left and right sides of the bot. now, have a beacon
set up that transmits signals... it just has to
transmit a signal, wait for like a second, and then
trasnmit another... the robot will have its central
antenna on at all times, waiting for that first
signal. when it recieves it, it turns on the other
two recieving antennas... when the signal comes, it
will reach one antenna BEFORE the other because that
antenna is closer. The difference between times would
be REALLY short, so the bot would have to have some
quick detecting circuitry (TTL... isnt that really
fast? fast enough?) this whole thing is kinda how our
ears work, sound reaches one side before the other.
any ideas on circuitry? or whether this thing would
even work? it would be good to help a bot home in on
its charging station... or other uses. anyway,
thanks.
=====
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|http://surf.to/photovore|
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|Evandude Dudzik |
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7291 Tue, 02 Nov 1999 16:07:13 -0500 [alt-beam] Re: aquabots - 'sealed' motor George Rix > but there has to be some sort of under pressure. When i used a
> little torch and heated the bulb, the almost melted glass went into
> the bulb and formed something like stalactite.
Then that one was probably a vacuum one - they ARE plentiful.
And since a vacuum is ultimate low pressure, the air outside the bulb has
extremely high pressure (comparatively), causing all the air outside of the
bulb to press inwards on the glass.
So when you melt it (or at least make it malleable), the outside pressure
forces it in some, until it cools and hardens too much.
Peace out!
Rob Rix
Don't take a walk, climb a tree =8B an ancient truism, invented last week.
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