Alt-BEAM Archive

Message #11944



To: beam@sgiblab.sgi.com
From: Bruce Robinson Bruce_Robinson@telus.net
Date: Wed, 15 Mar 2000 20:49:51 -0800
Subject: [alt-beam] Re: Bread Bored


CORBIT GIBERSON wrote:
>
> ... I was wondering where I could get my hands on a breadboard,
> as I'm likely to do a lot of fiddling to get things right. Is it
> possible to find one for a decent price?

And another $.02 heard from.

I use the JE series boards that Jameco sells. These have interlocking
tabs and double-sided tape on the back; you can gang them together and
stick them to a baseplate.

It's a nice way to get started -- one board with two detachable bus
strips set me back $10 CDN. As demand and finances permit, you can
simple add more pieces. Make your own baseplate, buy a couple of binding
posts, and you have an inexpensive, expandable system.

Of course, you will eventually end up with a huge board, because no
matter how big it gets, it's never enough :)

Regards,
Bruce



11945 Thu, 16 Mar 2000 16:22:28 +1100 Re: driving muscle wire "Jim Taylor"
> ACK that small stuff is more a pain then what it's worth (it's worth alot
> too). It's THE hardest stuff to crimp, it's impossible to use unless
it's
> crimped by the way....incase you have never worked with muscle wire before
> you NEED to crimp it to brass, and then solder it with a BIG BIG BIG heat
> sink on it. Or better yet, solder first crimp second.
> I had good sucess with a custom PCB with traces for the muscle wire
crimps,
> and driving circuits.
> I tried that smaller muscle wire with a higher voltage triggered SE. It
> wasn't too great, you prolly need at least 1 or 2F cap to get any kick
from
> it. Anything lower and you will just get a weak squirm from the wire.
>
>
>
>
> James Taylor
> "Edgar The Hate Bug"
> URL: http://fly.to/springmeadows
> ICQ 14888587
> ----- Original Message -----
> From: Richard Piotter
> To:
> Sent: Wednesday, March 15, 2000 1:39 AM
> Subject: Re: driving muscle wire
>
>
> > The thin, weak type is onlt 50 mA. Th larger stuff get's into larger
> > current values in the hundreds.
> >
> > David Perry wrote:
> > >
> > > thanks for the encouragement :-) Personally i'd be happy with a 4
> minute
> > > stroll - could prove rather expensive though :-) I think its quite
> > > possible - i think i'll use a a SE to save on weight (and batteries!)-
> it
> > > certainly won't be a fast moving critter though. Nitinol doesn't draw
> too
> > > much current (50ma) but it ain't too efficient. Should have all the
> parts
> > > tomorrow... See what happens. How was nitonol tricky for you?
> > >
> > > David
> > >
> > > ----- Original Message -----
> > > From: "Jim Taylor"
> > > To:
> > > Sent: Monday, 13 March 2000 11:52
> > > Subject: Re: driving muscle wire
> > >
> > > > ugh muscle wire......how I loved thee......I too tried to biuld a
> super
> > > > small walker using nitinol, some SMT parts, some really small
lithium
> > > > batterys, and some really thin music wire. I tried a 4 legger, a 6
> > > legger,
> > > > and a tilden worm. The 4 legger showed the most promise, and still
> does
> > > > looking back at my work. However Nitinol is very tricky stuff.
You
> mind
> > > > as well be directly shorting the batterys. Not only do they draw
alot
> of
> > > > current, but it doesn't transfer very well into torque. It seems
> (even
> > > with
> > > > BORIS, and STIQUITO) no matter how small your driver, and control
> board
> > > is,
> > > > you need alot of battery storage. Unless you like 4 minute strolls
:)
> > > >
> > > > Don't want to discourge you though.....My mini 4 motor walker walks
> fine
> > > on
> > > > a tether. However I don't think he will do any walking autonomously
> > > >
> > > >
> > > > >
> > > > >
> > > > > > To drive a muscle wire you do not even need half of an
h-bridge.
> The
> > > > > > second transisotr is used to provide a path for current flow.
All
> you
> > > > > > would need is an NPN transistor with the muscle wire connected
> between
> > > > Vcc
> > > > > > and the collector, the emitter connected to ground and the base
> > > > connected
> > > > > > to the input through a resistor. You will want the base resistor
> small
> > > > > > enough to drive the transistor into saturation and will probably
> need
> > > a
> > > > > > resistor in series with the muscle wire to control current flow.
> > > > > > I do not remember off the top of my head, but I think the 50
> micron
> > > > wire
> > > > > > nominally needs a 100mA current. I do not remember the
resistance
> > > (ohms
> > > > > > per unit length) off the top of my head. There are a couple
sites
> out
> > > > > > there with properties on muscle wires (www.dynalloy.com does I
am
> > > sure).
> > > > I
> > > > > > would definitely reccomend checking them out because they give
> other
> > > > > > helpful hints on using the wires, especially about attaching
them.
> > > > > > I did a concept project a while back using muscle wires for an
> > > > > > autonomous robot design class. From my experience, which is
> anything
> > > but
> > > > > > all inclusive, I found that the technology is fun and promising
> but
> > > > still
> > > > > > needs some work. You only get about a 5% deformation and the
power
> > > > > > required is still on the high side. I finally settled on a
design
> that
> > > > > > used four muscle wires for movement of legs down and back (2
> frames of
> > > 3
> > > > > > legs) and the reverse stroke was handled by a spring system to
> save on
> > > > > > power. I was using microprocessor control at the time, never got
> > > around
> > > > to
> > > > > > trying it with BEAM control. If I find time one of these days, I
> may
> > > go
> > > > > > back and finish that... I would be interested to hear what your
> > > > experience
> > > > > > with the wire is like. Best of luck.
> > > > > >
> > > > > > John Gonser
> > > > > >
> > > > > >
> > > > > > On Tue, 14 Mar 2000, David Perry wrote:
> > > > > >
> > > > > > > Okay - haven't asked a question for a while....
> > > > > > > Okay i'm making a robot, quite advanced, very, very tiny,
purely
> > > > because
> > > > > i
> > > > > > > had the idea for it and couldn't get it out of my head all day
> and
> > > > it'll
> > > > > > > drive me mad if i don't build it.
> > > > > > > The question is - what is the best way to drive muscle wire?
You
> > > would
> > > > > only
> > > > > > > use half a hbridge, (no need for switching wires) but i'm
> thinking
> > > > thats
> > > > > > > a little too large. Perhaps a 7hc245 would suffice. I need to
> drive
> > > 6
> > > > > > > pieces of 050 LT, any advice would be appreciated.Oh and why
am
> i
> > > > using
> > > > > > > muscle wire? - well i can't find 6x 4mm dia. gearmotors for
> under
> > > $31
> > > > > > > :-)
> > > > > > >
> > > > > > > thanks,
> > > > > > >
> > > > > > > David
> > > > > >
> > > > >
> > > > >
> > > >
> > > >
> > > > James Taylor
> > > > "Edgar The Hate Bug"
> > > > URL: http://fly.to/springmeadows
> > > > ICQ 14888587
> > > >
> > > >
> >
> > --
> >
> >
> > 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
> >
>

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