Subject:
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Re: sensors, actuators, and software, oh my!
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Newsgroups:
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lugnet.robotics
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Date:
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Fri, 4 Apr 2003 05:03:18 GMT
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Original-From:
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Steve Baker <sjbaker1@airmail.net^nospam^>
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Viewed:
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844 times
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Dan Novy wrote:
> Up for discussion.
>
> So, while discussing "the next big project," my ten year old and I
> tried to come up with a complete list of all the possible "signals"
> available at any one time that could be incorporated into a robot,
> whether practical, or useful or not. Questions like, "Does gravity
> count as a signal? It's "on" all the time, can be used to create motion,
> etc. There are standard signals or influencers (?) like light,
> temperature, atmospheric pressure, radio signals, tv signals, any RF
> stuff, etc. We were interested in what other people thought.
> So, the question is, standing in a room, or in an open field, how
> many signals/influence fields are passing through you at any one time,
> ready to be sampled?
One...or maybe infinity.
Most modern physicists believe that matter and energy are the same
thing - and that all forces can be described by some (as yet
undiscovered) "Unified Field Theory".
In that sense, there is one unified field that is EVERYTHING in the
universe.
If you approach it from the other direction, all radio, light, X-rays,
Cell-phone signals, Cosmic rays, etc are Electromagnetic waves - and
those can (in principle) exist at all frequences from the very longest
to the very highest.
Gravity is a different force - and since it's waves are not really
detectably right now, it doesn't appear as anything other than a force
in a direction - without a 'frequency'.
Then, there are the 'weak' and 'strong' nuclear forces - which is what is
really acting to keep matter doing what it does - so in a sense, those
are what is behind sound, air pressure, water pressure, wind, water
waves and large steel hammers! What we see as atoms pressing against
other atoms to make these effects can also be looked at as wave
probability functions (Electrons, Protons, etc) being acted upon
by fields - gravity, etc. When a "solid" object hits another one,
the forces that stop them merely swooshing straight through each
other are the 'weak' and 'strong' nuclear forces.
Counting the signals/fields (as you are trying to do) depends on what you
decide is your criteria for 'different'. Does red light count as a different
"signal" from blue light? How about red laser light would that be considered
different from non-coherent red light? What about Infra-Red signals...those
are only considered to be somehow different from normal Red light because we
can't percieve them with our human eyes - but your video camera (if it's a
really modern one) can see a little way into the infra-red - so the distinction
is a little arbitary...especially if you are a robot - to them, infra-red is
just a little bit more 'red' than regular red light.
Similarly, ultra-violet - is just a *more* blue shade of blue than
the shade that our eyes can see. It can also burn our skin - but then
so can visible light if it's bright enough (think about laser beams that
can cut steel using red light alone)!
You can extend what you mean by "light" as a separate signal until
you have to admit that in truth, radio waves are just very low
frequency light - yet more "red" than infra-red. Similarly,
X-rays are just higher frequency "light". There is no firm,
fixed physical difference between any of these things - which is
why physicists talk about "Electromagnetic Waves" to cover all of
those phenomena that we humans percieve as different.
Then, you look at "clearly" different forces - like the ones
that hold molecules together - and that keep atoms from falling
apart - and those too can be described mathematically with the
same equations as the electromagnetic waves. In recent years,
these 'weak' and 'strong' nuclear forces have been bound into
the same overall concept as the electromagnetic waves (There is
the "Electro-Weak force - carried by Electro-Weak fields).
So *TECHNICALLY*, you can roll it up into one big concept,
or slice it as thin as you like...considering each subtly
different colour of light as a different signal. Since
for any two colours you can imagine, there are an infinity
of subtle shades in between, you could say there were an
infinite number of 'signals' falling onto your robot as
white light.
So, to answer your son's question truthfully, the answer
is either "One" or "Infinity"...or anything in between -
depending on how you count them up.
How's that for a REALLY bad answer?!? :-)
---------------------------- Steve Baker -------------------------
HomeEmail: <sjbaker1@airmail.net> WorkEmail: <sjbaker@link.com>
HomePage : http://www.sjbaker.org
Projects : http://plib.sf.net http://tuxaqfh.sf.net
http://tuxkart.sf.net http://prettypoly.sf.net
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Message has 1 Reply:
 | | Re: sensors, actuators, and software, oh my!
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| (...) A: How many detectors do you have and what are their transfer functions? The reality is that it is the number of -observers- which matters. (...) No, they are not the same thing, they can be converted into each other according to a well (...) (21 years ago, 4-Apr-03, to lugnet.robotics)
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Message is in Reply To:
| | sensors, actuators, and software, oh my!
|
| Up for discussion. So, while discussing "the next big project," my ten year old and I tried to come up with a complete list of all the possible "signals" available at any one time that could be incorporated into a robot, whether practical, or (...) (21 years ago, 3-Apr-03, to lugnet.robotics)
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