[dorkbotbristol-blabber] The eyes! The eyes!

[Richard Sewell]

Ben - I've just been doing some googling - I don't think there's much in 
that book that you wouldn't find in this PDF:
http://www.dynalloy.com/pdfs/TCF1140RevD.pdf

Are you planning to be in HH on Tuesday ? I could bring the book and any 
experiments I have by then along.

R

voidnoise at googlemail.com wrote:
> I have been looking at that book online, would be great to had a look 
> inside it, thanks.
>
> Polystyrene was discussed last night -> cheap and light weight!
>
> If we could acquire some small cheap bearing, maybe salvaged from old 
> cd rom drive it could help reduce load on the actuators. Antons 
> prototype used pins and cardboard, and worked well, but im not sure 
> about robustness and scalability.
>
> On Oct 28, 2009 8:39am, Richard Sewell <richard at jarkman.co.uk> wrote:
> >
> >
> >
> > Ben - good stuff - sorry I missed the evening.
> >
> >
> >
> > If it helps, I have a copy of the Gilbertson muscle wire book
> > (http://www.amazon.com/Muscle-Wires-Project-Book-3-133/dp/1879896133)
> > which you are welcome to borrow.
> >
> >
> >
> > Although the wires have a decent pull force, it is only over a small
> > distance, so we don't have a great deal of energy available for moving
> > eyes. We might need to keep the eyes rather small and/or light in order
> > to be able to move them. We'll know that once we have some actuators
> > built.
> >
> >
> >
> > As for eyes, how about polystyrene balls ? Available in many sizes,
> > already mostly the right colour:
> >
> > http://www.polystyreneballs.com/moulded-ball-price.asp
> >
> >
> >
> > R.
> >
> >
> >
> > ben winstone wrote:
> > After a good brainstorming session last night I think we
> > have some nice ideas for the eyes. Anton has made an excellent
> > prototype with some wood and a pingpong ball. The momentum of thought
> > seems to be pro muscle wire for both cost and affect, but it may also
> > be worth pursuing magnets as an alternative. The trade name for muscle
> > wire seems to be Flexinol, and can be bought from rapid for about
> > £8/meter. It should safely reduce in size by between 3 & 5%, so
> > some levering would be required. It was discussed that we could
> > replicate the movements of real human eye muscles to perform the
> > desired action.
> >
> >
> >
> > So we need to buy some muscle wire! I will try and buy a reel tonight
> > when I am home from work.
> >
> >
> >
> > David H has said we should be able to use the university laser cutter
> > to manufacture the parts out of acrylic or wood. We just need a dxf cad
> > file to give to the machine.
> >
> >
> >
> > With regards to overall design ideas we have disccussed that larger eye
> > would mean less of them and so less electronics and overall work for
> > us, making the project much more achievable. This probably means an eye
> > somewhere between the size of a ping pong ball and a football. Any
> > ideas of what we could use for the eye? Also some thoughts were paid to
> > the arrangement of the eyes.
> >
> >
> >
> > I brought along a working demo of OpenCv face tracking to show how easy
> > it is to use, and I know Richard is looking using an mBed controller to
> > interface with a simple camera for blob detection. Se we probably have
> > both sides end of the face tracking covered, but will probably want to
> > use some extra simple sensors to add context to the presence of a
> > human.
> >
> >
> >
> >
> >
> > Thats all I can remember for now about last nights eye discussion.
> > Keeps the eyes coming and lets get on to some prototyping!
> >
> >
> >
> > Ben
> >
> >
> >
> > 2009/10/27 Richard Sewell richard at jarkman.co.uk>
> >
> >
> > Anton Bowers wrote:
> >
> > > I feel open loop would be better if it's at all possible, low cost
> > is
> >
> > > more important than accuracy (assuming we want to make a low
> > number of
> >
> > > hundreds of eyes).
> >
> > >
> >
> > >
> >
> >
> >
> > Sadly, I don't think we can do open loop with muscle wire. It's got a
> >
> > lot of built-in hysteris. Magnets & coils (or even bits of iron
> > wire &
> >
> > coils) ought to be a lot more inherently linear. Might be hard to get a
> >
> > large output angle, but perhaps that can be fixed with linkages.
> >
> >
> >
> > I guess we need to make our trial actuators, then see if our ambition
> >
> > stretches to two eyes or two hundred.
> >
> >
> >
> >
> > R
> >
> >
> >
> > ........................................................................
> >
> > .........dorkbot: people doing strange things with electricity..........
> >
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> >
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> >
> >
> >
> >
> >
> >
> >
> >
> >
> > ........................................................................
> > .........dorkbot: people doing strange things with electricity..........
> > ..........................http://dorkbot.org............................
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