Alt-BEAM Archive
Message #11197
To: alt-beam@egroups.com
From: Ben A Micklin kcimb@juno.com
Date: Wed, 1 Mar 2000 09:22:53 -0600
Subject: [alt-beam] Re: VCR dissection
If you can, pull ALL the ics out of the sockets.
The go for capacitors. Then, go for 2.2k resistors, etc......
~ben~
On Tue, 29 Feb 2000 20:23:39 -0800 "Dave G. Amundson"
writes:
> I've just rediscovered BEAM, and am starting to take apart an old VCR
> with intent to build my first robot. I know I'm not going to find
> everything I need in it, but I'm just wondering what sort of stuff I
> should be looking for. I'm obviously going to pull the motor, and I
> plan to pop as many resistors off the circuit boards as I can. Is
> there anything else I should look for? Any general advice for
> taking
> apart electronics? I'm completely new at this. Thanks for any
> help.
>
> --
> Yours etc.,
> Dave G. Amundson
>
>
>
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11198 Wed, 1 Mar 2000 09:09:24 -0600 [alt-beam] Re: Si vs. Sunceram alt-beam@egroups.com Ben A Micklin But when you put them in series and they produce over 4.0 v, doesn't it
screw up polarity or something like that?
~ben~
On Tue, 29 Feb 2000 23:51:09 EST Bumper314@aol.com writes:
> In a message dated 2/29/00 6:25:04 PM Mountain Standard Time,
> mikekulesza@hotmail.com writes:
>
> > I only saw those small cells at radio shack, that give 300 mA @
> .55V. Break
> > that into say..... hmmm.... 8 pieces, connect in series, and you
> get 37.5
> mA
> >
> > @ 4.4 V. Thats seems ALOT better than any sunceram. And the
> overall size
> is
> > smaller too. And also better looking. Now I use suncerams myself,
> and know
> > that they are nice. But why do the silicon cells apparently
> "suck"? Here,
> in
> >
> > theory they're way better than sunceram. So are suncerams really
> better in
> > practice, but worse in theory? hmmmmm....
>
> Save exact area as the larger sunceram I believe. That puts out 5.5v
> at how
> many mA?
>
> Steve
>
>
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11199 Wed, 1 Mar 2000 07:31:21 -0800 [alt-beam] Re: mini walker "'beam@sgiblab.sgi.com'" Wilf Rigter Hi Ben,
I'm a great fan of your beam designs (and other insightful postings) many of
which have sparked new ideas for me. So sorry for recycling "old" ideas but
this one seem to have some interesting "wrinkles" which I thought you'd
appreciate. This reverser circuit works by switching between 2 sets of
drivers (1+2) when the reverse switch is tripped. The drivers for the first
motor are in parallel and therefore not reversed when selecting 1 or 2. But
the drivers for motor 2 swap inputs between Nv2 and Nv4 thereby "reversing"
the phasing on motor 2. Note the memory cap for the reverse switch Nu
circuit keeps which keeps its charge for x steps rather than x seconds.
That's important because with a normal reverse Nu, the walker would
repeatedly collide with the same obstacle when the light is low ie the
walker may only step once before a conventional reverse Nu times out .
The memory cap is discharged a little every step cycle and remains active
for x steps before the reverse Nu times out. The design may need fine tuning
because standby current rises when the Nu cap voltage enters the linear
region and a Bolt/Hitchcock sampler circuit may be needed to reduce standby
current. As you can see there is lots of room for improvement and I hope you
have some time to find some elegant solutions.
regards
wilf
> -----Original Message-----
> From: Ben Hitchcock [SMTP:beh01@uow.edu.au]
> Sent: Wednesday, March 01, 2000 3:18 AM
> To: beam@sgiblab.sgi.com
> Subject: Re: mini walker
>
> Wilf,
>
> As usual, you manage to beat me to the punch.
>
> One question though, on the schematic you posted I couldn't figure out how
> the second and fourth pair of motor drivers from the left worked.
>
> On the first and third pair, the inputs for each pair are connected
> together. The second and fourth pair seem to share their inputs. Is this
> a
> typo? Or are you doing something very funky? Is this part of the
> reverser
> circuit? If it's not a typo then what prevents the drivers from driving
> against each other?
>
> Ben
>
> ----------
> >From: Wilf Rigter
> >To: "'beam@sgiblab.sgi.com'"
> >Subject: RE: mini walker
> >Date: Wed, 1 Mar 2000 16:26
> >
>
> > Hi Ben,
> >
> > Here is a blast from the past (June 99) : the LIGHT WALKER 1.0 design
> as
> > shown in the attached schematic. In this design the SE function has been
> put
> > inside the microcore loop. From another perspective this is a pentacore
> > design. The 1381 acts like a combination Nu, PNC and SE trigger. Note
> that
> > the 74HC14 and AC240 are powered up all the time. Normally the 4Nv
> outputs
> > will all be high, the motors will be stopped and no current will flow.
> The
> > solar panel will charge up the main cap and also the memory cap of the
> 1381.
> > The memory cap ensures that the 1381 input voltage will not drop during
> the
> > first process interval when the motor current starts to pull down the
> main
> > capacitor voltage. When the 1381 fires it "injects" a process into the
> first
> > Nv with a rising edge. This process ripples through the other Nvs and
> when
> > the process reaches the last Nv it resets the memory cap of the 1381.
> This
> > sequence is a 4Nv process cycle which causes the bot to advance by one
> step
> > on each leg. Next the solar panel charges the main capacitor and the
> 1381
> > memory cap back up and when fully charged the 1381 triggers the next
> process
> > cycle. If there is enough charge on the main cap the SE fires almost
> > immediately and the walker continues uninterrupted. This embedded SE
> design
> > can be extended to 6Nv or 8Nv designs as well.
> >
> > The reverser circuit is quite a nice solution to the problem of early
> > reverser time out when the LIGHT WALKER only walks intermittently. To
> avoid
> > this problem, the reverser memory capacitor is discharged in steps, one
> > process cycle at time, with about 7 or 8 cycles required to return to
> > forward motion regardless of the time between steps. In addition the
> > reverser circuit switching is synchronized with the start of each cycle
> to
> > avoid the typical gait recovery time associated with asynchronous
> reverser
> > circuit switching. This synchronous reverser idea can be applied to many
> > walker designs and imho is a nice contribution to the state of the art
> of
> > BEAM tech.
> >
> > The LIGHT WALKER still needs tactile inputs. Perhaps it can be left as
> an
> > exercise for the reader to complete the full LIGHT WALKER design.
> >
> > enjoy
> >
> > Wilf Rigter mailto:wilf.rigter@powertech.bc.ca
> > tel: (604)590-7493
> > fax: (604)590-3411
> >
> >
> > <>
> >
> >
> >
> >> -----Original Message-----
> >> From: Ben Hitchcock [SMTP:beh01@uow.edu.au]
> >> Sent: Tuesday, February 29, 2000 7:38 PM
> >> To: beam@sgiblab.sgi.com
> >> Subject: Re: mini walker
> >>
> >> Here's an idea:
> >>
> >> You don't need a SE!
> >> Just attach the 1381 to power and ground, andconnect the output of the
> >> 1381 to the input of the microcore via a normal microcore cap. The
> 1381
> >> gets to its switch-on voltage, introduces a process, and bang off it
> goes.
> >> No need to enable or disable the 240. And have the process fall of f
> the
> >> end of the core - four neurons in a chain. This means that you get to
> >> gang two gates together per coil lead - two gates ganged up would give
> you
> >> enough juice to drive the walker, methinks. And the nice thing about
> this
> >> is that you only need one chip, one 1381, four caps and resistors, plus
> >> your coils and solar panel and storage cap and that's it!
> >>
> >> Too easy.
> >>
> >> Ben
> >>
> >> > I was thinking about using a microcore instead of a master slave
> bicore.
> >> > Either way, can pulses be stopped and resumed from their last
> position?
> >> > I'm wondering if an Nv chain that is initiated by the SE firing would
> >> > work. Switch the source to a different coil and polarity on each of 4
> >> > steps, and then fall off the end. Allow the SE to charge to full.
> It'd
> >> > store enough power for a complete step cycle. If there were enough
> >> > power, I assume the SE could continuously fire the start of the Nv
> >> > chain, till light levels drop and it would then rely on firing
> >> > intermittently, till it looses it's charge again.
> >> >
> >> > Has anyone made such a circuit before???
> >> >
> >> > Would the Chloroplast be suitable for this purpose, and how can I get
> a
> >> > single pulse out of it, with a second sustained pulse going to the
> >> > driver (I suppose 2 chips would be acceptable, if necessary). If the
> >> > driver powers the coils, then would it be possible to attach it to
> the
> >> > steady voltage output of the Chloroplast SE and the pulse to the
> >> > trigger, and have a very high dropout level, so it shuts down right
> >> > away, waiting for the next charge before refiring???
> >> >
> >> >
> >> > Ben Hitchcock wrote:
> >> > >
> >> > > Hi,
> >> > >
> >> > > > What
> >> > > > would be best? I thought of an SE type system with a timed
> trigger.
> >> Is
> >> > > > there a way to create an SE that triggers different pulse outputs
> in
> >> > > > chain? I'll play with circuits. That's what we're here for
> anyway.
> >> New designs!
> >> > >
> >> > > How about using a shift register? Attach the SE to an enable pin
> on
> >> your
> >> > > motor driver (74xx240) and also to the clock pin on the shift
> >> register.
> >> > > You'll also need to attach the fourth (or is it fifth?) pin of the
> >> shift
> >> > > register to the data in
> >> > > pin, and somehow start a pulse when there aren't any in the
> stream...
> >> > > you'd need four diodes (one from each gate on the shift register) a
> >> > > resistor and an inverter to create a pulse if none existed in the
> >> chain.
> >> > >
> >> > > Maybe a shift register isn't such a good idea after all... 2 IC's
> >> instead
> >> > > of one... Perhaps ye olde microcore could be adapted to do it.
> >> > >
> >> > > Good luck!
> >> > >
> >> > > Hmm maybe the bot won't be able to steer using this setup. no
> matter,
> >> it
> >> > > will look pretty cool.
> >> > >
> >> > > Ben
> >> >
> >> > --
> >> >
> >> >
> >> > Richard Piotter The Richfiles Robotics & TI web page:
> >> > richfile@rconnect.com http://richfiles.calc.org
> >> >
> >> > -- Make Money by Simply Surfing the Net or responding to E-Mail!!!
> >> > -- Click below!!!
> >> >
> >> > http://www.alladvantage.com/go.asp?refid=ATL147
> >> > http://www.spedia.net/cgi-bin/dir/tz.cgi?run=show_svc&fl=8&vid=329630
> >> >
> >>
> >>
> >> --
> >> Nothing is foolproof to a sufficiently talented fool.
> >
11200 Wed, 01 Mar 2000 11:22:01 -0500 [alt-beam] Re: walker leg attachment beam@sgiblab.sgi.com "Sathe Dilip" I bought mine at Radio Shack. They have some 4 types (3 sizes). I
don't remember which type I have but you can possibly get a size that
will match your motor/gearbox shaft. The catalog I have here shows the
following part numbers:
270-680
270-678
270-679
270-677
Dilip
------------------------------------------------
"Travis D." wrote:
>
> Just out of curiousity, where do people generally buy
> the terminal blocks to attach the walker legs to the
> motor shafts (part #?)...
SNIP
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11201 Wed, 1 Mar 2000 08:07:29 -0500 Re: Symets with legs
> my symet is one that has the typical symet look with 4-fold rotation
> symmetry, and a buncha heat shrink as a ball actuator. I sent William
> (robot-central) a tutorial that has some pics, which should be up sometime
in
> the near future. i added four wire extentions to lessen the angle at which
it
> leans at. I got the idea looking at the beamart web page (your bots bring
> tears to my eyes). has anybody done anything similiar, i want to see how
to
> modify its behavior to be a little more effecient (such a trite word by
now,
> better get my thesorus). just tinkerin'
>
> -Spencer
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