Alt-BEAM Archive
Message #06814
To: "'beam@sgiblab.sgi.com'" beam@sgiblab.sgi.com
From: Wilf Rigter Wilf.Rigter@powertech.bc.ca
Date: Sun, 17 Oct 1999 08:27:36 -0700
Subject: [alt-beam] Re: Radio Communications?
Thanks to Steven Bolt, the transducer and glue circuits are ready to build.
The processing and influencing is done with a microcontroller and
therefore a beam equivalent of that needs to be designed.
regards
Wilf Rigter mailto:wilf.rigter@powertech.bc.ca
> -----Original Message-----
> From: Senior [SMTP:kyled@scruznet.com]
> Sent: Saturday, October 16, 1999 7:51 PM
> To: beam@sgiblab.sgi.com
> Subject: Re: Radio Communications?
>
> Richard Caudle wrote:
> >
> > I've always thought that sound would be the optimum thing to use for
> > communicating. More biomorphic than radio! I don't have the design
> skills
> > to make it though.
> >
> > Richard
>
> Oh true indeed. Check out steven bolt's work at
> http://www.xs4all.nl/~sbolt/
> and look at his spider's sound system.
> Very good work!! I haven't built it but it looks very doable and CHEAP,
> as all of his circuits are. Check it out!
> Kyle
>
6815 Thu, 17 Jun 1999 10:21:02 -0500 [alt-beam] Re: Radio Communications? beam@sgiblab.sgi.com Richard Piotter Nvs Can do a lot of things that flip flops can. not exactly, but close.
the biggest difference would have to be the clock. Nvs provide their own
yiming based on the RC charging time and the input current. Flkip Flops
take a steady clock signal and react to a high or low when the clock triggers.
I believe it cou;ld be done, or at least approximated, if not better.
Nvs are more dynamic and even chaotic than Flip Flops. I had a teacher
ask why I used RC time delay circuits rather than a flip flop based
counter. My reply was simply that these things are more dynamic. They
change. They aren't fixed. That's what I like about them!
Tell us what issue. I'd like to try this, seeing as I have a heap of 74HC14s!
--
Richard Piotter
richfile@rconnect.com
The Richfiles Robotics & TI web page:
http://richfiles.calc.org
For the BEAM Robotics list:
BEAM Robotics Tek FAQ
http://people.ne.mediaone.net/bushbo/beam/FAQ.html
6816 Thu, 17 Jun 1999 10:34:30 -0500 [alt-beam] Assosiative Memories beam@sgiblab.sgi.com Richard Piotter Issue? Year, month???
Sean Rigter wrote:
> ...if workers had a memory loop to mber the path taken from the
> foraging site to the hive...
>
>> I once read in Scientific American that associative memory could be
built with
>> discreet components. They were using JK flip/flops to accomplish
this. Is it
>> possible to do it
>> with BEAM 'bots? These flip/flop circuits look suspiciously like Nv circuits...
>>
>> Richard
>> []--/\/\/--[]
--
Richard Piotter
richfile@rconnect.com
The Richfiles Robotics & TI web page:
http://richfiles.calc.org
For the BEAM Robotics list:
BEAM Robotics Tek FAQ
http://people.ne.mediaone.net/bushbo/beam/FAQ.html
6817 Sun, 17 Oct 1999 08:49:25 PDT [alt-beam] walker behaviours alt-beam@egroups.com "Patrick Yeon" I read in a reader's digest that Mr. T had a certain robot which he realy
liked. It would find the best light spot then go around in circles. When an
other robot would go in that circle the circling robot would crush it and
push it to the outside. Eventually the robot would have a wall around it. I
wanted to know, how did he get such a behaviour because I'd like to have
some bots with the same kind of behaviour.
PAT
______________________________________________________
6818 Sun, 17 Oct 1999 10:53:22 -0600 [alt-beam] Re: IR object sensor and jammer "beam@sgiblab.sgi.com" "Dan Larson" I have some thoughts on this.
I have worked with IR proximity detection with robots, so I know
a few things.
The IR receiver modules have a automatic gain control in them
that allows them to be more sensitive for weaker signals and
less sensitive for stronger signals that might overload the
them.
It might be possible to shine a super bright IR beam at 40Khz
directly into the receiver to prevent it from getting any
useful data. The reciever would have to turn the gain way
down, and consequently, would not be able to detect its own
*weak* signals. This would no doubt appears to the robot
as a false sensor hit, "frightening" it away.
As pointed out, users of these receivers for
proximity detection often purposefully attenuate the output
of their IR LEDs to get a more useful range, closer to the
robot. The technique I use with my IR LEDs is to modulate
them off-frequency *and* increase the current limit resistors
in series with he LEDs.
If someone came along with an IR beam right on frequency, they
would no doubt swamp my detectors.
Keep in mind, that these receivers come in a variety of
frequencies: 32khz, 38khz, 40khz, and 56.8 khz. I use
56.8khz modules to avoid interference from common remote
controls. An effect countermeasure would require emitting
all common frequencies.
Direct sunlight can also swamp the detectors, but since it
is a "DC" source of light, it does not register as a false
hit. A robot using a very bright unmodulated IR source
may be able to swamp the receiver of the victim without
frightening it away.
The problem with making a very bright *unmodulated* source
of IR light is the the LEDs can only take small continuous
currents. Remotes use very high current through the LEDs, but
remember that they are *modulated*, that is not turned on
continuously. With a 10% duty cycle, you can generally run an
IR LED at 10 times it rated continuous current without
letting out the magic smoke. This trick can't be used for a
DC light source.
Have fun experimenting.
Dan
On Sat, 16 Oct 99 17:41:09 -0600, Ian Bernstein wrote:
>Hi
>I've built a few IR object detectors which use the sharp IR detector and
>a 40K emitter that will give me a range of about a foot max. If I disable
>the emitter and use my TV remote I get a range of like 8 feet. Why is
>that? And is there a schematic for an emitter circuit like the one in my
>TV remote?
>Also is there a way to jam a 40K object detector so it won't pick up an
>object that has the jammer on it. I think I remember something about
>emitting a 80K signal but I don't remember.
>
>Thanks, Laterz
>
>--------
>There is only one true "SyNeT"
>BEAM Online - http://www.beam-online.com
>
> Always remember you're unique, just like everyone else.
>
>
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