Alt-BEAM Archive

Message #05372



To: beam@sgiblab.sgi.com beam@sgiblab.sgi.com
From: Darrell Johnson beamtastic@yahoo.com
Date: Friday, 23 July 1999 2:49
Subject: Re: Contest Entry!



>Nothing sneaky about it. The bot's been 95%done for over two months
>now. I just put some minor mechanical touches on it (tension spring)
>the other day to finish it off.
>No need for conspiracy theories here.... :)
>
>darrell
>
>--- David Perry wrote:
>> this has a reallllly sneaky similarity to my bot,
>> your controller looks more
>> flash than my pentacore but my robot can turn and
>> reverse, rather well
>> actually.
>> I've taken a couple of photos, all i have to do is
>> finish the other 3
>> h-bridges, install the tactile sensors, and, if i
>> have time (and parts!)
>> i'll solarize it. Still, out bots are sneakingly
>> similar, both snakebotish.
>> Very cool never the less, i think our entries will
>> come very, very close. by
>> the way bruce, thanks for that cold start PNC, it's
>> FANTASTIC, it'll lock
>> into sequence no matter what.
>> ohhh, i'm nervous now, official competition.
>>
>> David Perry
>>
>> -----Original Message-----
>> From: Darrell Johnson
>> To: beam@sgiblab.sgi.com
>> Date: Thursday, 22 July 1999 6:26
>> Subject: Contest Entry!
>>
>>
>> >Hello everyone, My contest entry is done and ready
>> for viewing...
>> >
>> >Mod-Worm 1.0
>> >here's the link:
>> >http://www.beamzine.com/contest/DJohnson/index.html
>> >
>> >check it out!
>> >
>> >-darrell
>> >
>> >--
>> >_______________________________
>> >BICOREEOS..they're BEAMtastic!!
>> >http://home.pacbell.net/wundoba
>>
>>
>>
>
>===
>_______________________________
>BICOREEOS..They're BEAMtastic!!
>http://home.pacbell.net/wundoba
>_________________________________________________________
>Do You Yahoo!?
>


5373 Thu, 22 Jul 1999 16:28:44 -0700 [alt-beam] Re: solar cell v doubler alt-beam@egroups.com Les Davis But if you ask nicely, they will send you a free sample chip (MAXIM that
is, not Digi-Key)

Les

Don Papp wrote:
>
> On Wed, 21 Jul 1999, Sean Rigter wrote:
>
> > design. Check out Maxim for some of the best
> > (but not cheapest) solutions.
>
> Also, I find that many of the cooler Maxim parts are not available
> in Digi-key's inventory (yet?)....
>
> | Donald Papp
> | don@oa.net
>
> ------------------------------------------------------------------------
> Was the salesman clueless?
> Productopia has the answers.
> http://clickhere.egroups.com/click/555
>
> eGroups.com home: http://www.egroups.com/group/alt-beam
> http://www.egroups.com - Simplifying group communications



5374 Thu, 22 Jul 1999 20:19:01 -0400 [alt-beam] Re: Hoverbot & balancing acts ( was: LEGO lawnmower) beam@sgiblab.sgi.com "George Rix" I'm really, REALLY sorry, Wilf, but I'm afraid I understand maybe three
words in that whole paragraph. Maybe I need some coffee. I just got up, you
see.
Signing off,
Rob Rix

___________________________________________________________________________
'I guess I picked the wrong week to stop sniffing glue' - from Airplane

----------
>From: Wilf Rigter
>To: "'beam@sgiblab.sgi.com'"
>Subject: RE: Hoverbot & balancing acts ( was: RE: LEGO lawnmower)
>Date: Thu, Jul 22, 1999, 4:10 PM
>

> Hi Rob,
>
> Yes! Well at least the equivalent of a self adjusting pot. It uses very long
> time constant (hours) cascaded memory Nu's which by (intelligent) "trial and
> error" acquire a combination of high and low Nubits depending on external
> "error" conditions which are locked in when the "error" is "corrected" and
> use these Nubits to form a binary value that can be used with resistors as a
> D/A to adjust the TC of an Nv etc. ( all that in one sentence!) In some case
> just one bit, is sufficient in others 4 or 8 bits may be needed for higher
> resolution "fine tuning" a process



5375 Thu, 22 Jul 1999 17:56:03 -0700 [alt-beam] Re: Being less than dizzy (was: balancing acts ( was: LEGO lawnmo "'beam@sgiblab.sgi.com'" Wilf Rigter Hi Zoz,

let's see you balance one of those hinged yard sticks on your finger tip. It
seems like an intractable problem since if both sections are falling over in
the same direction there is no action of the cart that can correct that. Are
you sure there is a solution?

and then you wrote:

Still -- I think this points out a distinct problem area for BEAM design.In
spite of anything that has been said about temporal encoding and all of the
rest of that jazz, what you are talking about is still a bang-bang (i.e.
full on or full off) kind of system. For example, in the case of 'head',
the corrections being made have the same force in either direction and it is
the differences in the length of correction that permit tracking. I guess
one could use two --independent-- bicores (one for each sensor) to achieve
some sort of pulse-width-modulation effect. The two connections to the motor
would be connected to one output each and the bicores would operate at a
frequency one or two orders of magnitude than the ones we usually see. A
rough schematic would be:

sensor -- bicore -- motor -- bicore -- sensor

I wonder what the results would be. Would the net effect be smoother?
Would it take less power? Could it be made to work at all?

to which I reply:

Your point about "distinct problem area for BEAM design" is kind of ironic,
since you next suggest a solution using a pure BEAM Dual Bicore PWM head
design, proving that this is not a "distinct problem area for BEAM design"
at all! When you analyze typical BEAM circuit operation you find a level
of detail usually overlooked because of the apparent simplicity of the
design. Too often BEAM designs are just used as black boxes which is a pity
since BEAM circuits ( unlike Pentium chips) are so exquisitely simple that
is possible for anyone to learn to fully understand them. Besides everyone
knows that even the simplest Bicore head circuit already uses "Pulse Width
Modulation" right? Would the DBPWM head operation be smoother? Would it use
less power? Experiment!

regards

Wilf Rigter mailto:wilf.rigter@powertech.bc.ca
tel: (604)590-7493
fax: (604)590-3411

> -----Original Message-----
> From: John A. deVries II [SMTP:zozzles@lanl.gov]
> Sent: Thursday, July 22, 1999 1:49 PM
> To: beam@sgiblab.sgi.com
> Subject: Being less than dizzy (was: balancing acts ( was: LEGO
> lawnmower))
>
> At 08:11 PM 07/21/1999 , Wilf Rigter wrote:
> >Nice topic Zoz!
> >
> >Try a 2DOF balancing act with a 4 foot rod on the tip of your finger.
>
> As it turns out, back when I was working at Lockheed in Sunnyvale,
> California & we had time on our hands we'd do basically what you are
> describing with a yardstick. Eventually someone remembered or figured out
> that what you are working with is an inverted pendulum (as long as the
> object being balanced is perfectly rigid). This meant that the longer the
> object is, the lower its characteristic frequency will be: longer meant
> easier to balance. If you try balancing a pencil and then a ... let's say
> meter stick just to be more international ... you'll see what I mean.
>
> Richard Weait commented:
>
> >OH Zoz! Like the rod in one dimension or two isn't difficult enough!
> >A jointed rod!?!?!? Ouch! But jointed in how many dimensions? And
> >if one joint; in the same axis, or orthogonal?
>
> If I remember correctly, this was basically a planar problem. In other
> words, the rotation of each hinge occurs in the same plane. I seem to
> remember that it isn't really that much more difficult than the single rod
> problem. A crummy sketch would look like:
>
>
> /
> /
> /
> /
> o hinge
> \
> all in the plane of your screen
> \
> \
> \
> o hinge
> -----------
> ---cart--- wheeled
> cart that can move left or right
> -----------
> o o
>
>
> Still -- I think this points out a distinct problem area for BEAM design.
> In spite of anything that has been said about temporal encoding and all of
> the rest of that jazz, what you are talking about is still a bang-bang
> (i.e. full on or full off) kind of system. For example, in the case of a
> 'head', the corrections being made have the same force in either direction
> and it is the differences in the length of correction that permit
> tracking.
> I guess one could use two --independent-- bicores (one for each sensor)
> to
> achieve some sort of pulse-width-modulation effect. The two connections
> to
> the motor would be connected to one output each and the bicores would
> operate at a frequency one or two orders of magnitude than the ones we
> usually see. A rough schematic would be:
>
>
> sensor -- bicore -- motor -- bicore -- sensor
>
>
> I wonder what the results would be. Would the net effect be smoother?
> Would it take less power? Could it be made to work at all?
>
>
> Z
>
>
>
> ---------------------------------------------------------------
>
> Do you have a BEAM question?
> Try one of the following sites -- they really help!
>
> BEAM Mailing List Archive http://www.egroups.com/list/alt-beam
> Advanced BEAM Mailing List http://www.egroups.com/list/spinalcolumn
> BEAM Heretics http://www.serve.com/heretics/
> BEAM Robotics Tek FAQ
> http://people.ne.mediaone.net/bushbo/beam/FAQ.html
> BEAM Mailing List Archive http://www.egroups.com/list/alt-beam/
> BEAM Online http://www.beam-online.com/
> Chiu-Yuan's BEAM Page http://www.geocities.com/SouthBeach/6897/



5376 Thu, 22 Jul 1999 19:01:30 -0700 [alt-beam] Re: Hoverbot & balancing acts ( was: LEGO lawnmower) "'beam@sgiblab.sgi.com'" Wilf Rigter Hey, I'm not trying to be obscure but then neither is it meant to be real
easy. It has to be a bit of a challenge or else it wouldn't be fun and don't
worry, don't be sorry, I get my best ideas from misunderstanding what other
people are trying to say. (grin)

I really try not to take myself too seriously and hope nobody else does
either.

Sip some of these BEAM ideas like a good cup of coffee and if you like what
you taste, figure out how it was made and write down the ingredients. Or
design yourself a self adjusting coffee pot (grin). And remember, ask the
right question, get the right answer since garbage in = fertilizer out

enjoy!

Wilf Rigter mailto:wilf.rigter@powertech.bc.ca
tel: (604)590-7493
fax: (604)590-3411


> -----Original Message-----
> From: George Rix [SMTP:rix.g@bmts.com]
> Sent: Thursday, July 22, 1999 5:19 PM
> To: beam@sgiblab.sgi.com
> Subject: Re: Hoverbot & balancing acts ( was: RE: LEGO lawnmower)
>
> I'm really, REALLY sorry, Wilf, but I'm afraid I understand maybe three
> words in that whole paragraph. Maybe I need some coffee. I just got up,
> you
> see.
> Signing off,
> Rob Rix
>
> __________________________________________________________________________
> _
> 'I guess I picked the wrong week to stop sniffing glue' - from Airplane
>
> ----------
> >From: Wilf Rigter
> >To: "'beam@sgiblab.sgi.com'"
> >Subject: RE: Hoverbot & balancing acts ( was: RE: LEGO lawnmower)
> >Date: Thu, Jul 22, 1999, 4:10 PM
> >
>
> > Hi Rob,
> >
> > Yes! Well at least the equivalent of a self adjusting pot. It uses very
> long
> > time constant (hours) cascaded memory Nu's which by (intelligent) "trial
> and
> > error" acquire a combination of high and low Nubits depending on
> external
> > "error" conditions which are locked in when the "error" is "corrected"
> and
> > use these Nubits to form a binary value that can be used with resistors
> as a
> > D/A to adjust the TC of an Nv etc. ( all that in one sentence!) In some
> case
> > just one bit, is sufficient in others 4 or 8 bits may be needed for
> higher
> > resolution "fine tuning" a process



5377 Thu, 22 Jul 1999 20:43:35 -0700 [alt-beam] Re: Solar cell v. doubler "'beam@sgiblab.sgi.com'" Wilf Rigter
content-type: text/plain

Well, surprise!

Efficiency is not too shabby especially for the Bicore Charge Pump. About
70% with 3.4V in and 5.5V out @ 50 ma. I tested this with a 74AC04 and
1N4148 diodes so a 74HC/AC240 with Shottky diodes should give even better
performance. An interesting feature of the fullwave charge pump is that it
requires no output filter since it generates pure DC out. At 2.6V input, the
tested 74AC04 Bicore Charge Pump easily drives a BG micro gear motor at over
4V out. How the efficiency of a system as a whole is affected is quite
complicated. For example, I remember an article which demonstrated the
overall efficiency of a solar cell battery charging system was increased by
adding a dc to dc converter despite the converter losses, by loading the
solar cell to operate at it's maximum power output point and optimizing the
output voltage and current to match battery charging characteristics.

enjoy

Wilf Rigter mailto:wilf.rigter@powertech.bc.ca
tel: (604)590-7493
fax: (604)590-3411


<>


> -----Original Message-----
> From: Sean Rigter [SMTP:rigter@cafe.net]
> Sent: Tuesday, July 20, 1999 9:40 PM
> To: beam@sgiblab.sgi.com
> Subject: Re: Solar cell v. doubler
>
> Maybe netscape is better for compatability. So here is the somewhat
> optimized
> and tested micro-chargepump circuit (ucpump.gif) . Depending on the
> solarcell, I estimate it will charge a 0.047F cap to 5V in one or two
> minutes. The coupling cap can be increased to 47 uf for slightly improved
> efficiency. Note the polarity of the coupling cap. The current into the
> main
> cap at 4.5V is about 10ma with 25 ma drawn from a 3V source so efficiency
> is
> not it's strong point but simplicity and cost certainly is. Milage may
> vary.
>
> regards
>
> wilf
>
> JNNREaton@aol.com wrote:
>
> > "Solarcel.mim"
> >
> > Wilf,
> > Thanks for all the great circuits. What application do I need to read
> an
> > "mim" file? I can download it, but I cannot open it.
> > Thanks.
> > Jim Eaton
> > LaCrescent Minnesota << File: UCPUMP.gif >>



Attachment: bcpump.gif

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