[Noisebridge-discuss] driving multiple LEDs with minimal batteries

[jim]

   thanks for the links. 
   they bring to mind the possible need for a switch 
to spare battery life. 


On Tue, 2011-01-04 at 22:43 -0800, T wrote:
> 
> 
> 
> 
> http://www.instructables.com/id/LED-Throwies/
> 
> 
> http://graffitiresearchlab.com/projects/led-throwies/
> 
> 
> 
> On Tue, Jan 4, 2011 at 20:36, jim <jim at well.com> wrote:
>         
>         
>           the best battery i could find on short notice
>         seems to be the CR2450, size and weight about
>         like a quarter ($0.25), a pretty good match for
>         small fabrics. it presents 3 VDC at up to 30 mA
>         constant current, enough to drive a few LEDs at
>         reasonable brightness.
>           keeping in mind he possible requirement of
>         minimal size and weight so's to be incorporated
>         in a scarf or other small garment, what other
>         battery is suitable?
>         
>         
>         
>         
>         
>         
>         On Tue, 2011-01-04 at 20:21 -0800, Christoph Maier wrote:
>         > On Tue, Jan 4, 2011 at 12:06 PM, meredith scheff
>         <satiredun at gmail.com> wrote:
>         > > I'd like to do a soft circuit scarf or three, but I'm
>         always running up
>         > > against the problem of power. I usually use fairly low
>         power LEDs
>         > > (<2v) driven by a 9v battery or one of sparkfun's LiPos.
>         > > I've heard tell of somehow being able to power more, but
>         I'm still learning
>         > > this EE stuff. Could some kind person point me in the
>         right direction?
>         > > Meredith
>         > >
>         > > --
>         > >
>         > > Ladycartoonist.com
>         >
>         > A MESSAGE FROM THE DEPARTMENT OF OVERENGINEERING
>         >
>         > I''m sitting here in the lab of a fellow (of the IEEE),
>         >
>         [ http://pony.noisebridge.net/~cmaier/wearables/lab_with_stuff.jpg ]
>         > trying to make contributions to biomedical instrumentation,
>         > but I'm always running up against the problem of making
>         circuits
>         > actually comfortably wearable.
>         > We usually end up using little PCBs (< quarter sized) and
>         copper wires
>         > or ribbon cables.
>         > I've heard tell of some folks who make costumes that blink
>         with sound,
>         > or dresses that point north,
>         > but I have no clue about this tailoring stuff.
>         > Could someone match me up with a talented seamstress?
>         > [For all you Terry Pratchett fans: Not THAT kind of
>         seamstress!]
>         >
>         > > ___________
>         > >
>         > > A human being should be able to change a diaper, plan an
>         invasion, butcher a
>         > > hog, conn a ship, design a building, write a sonnet,
>         balance accounts, build
>         > > a wall, set a bone, comfort the dying, take orders, give
>         orders, cooperate,
>         > > act alone, solve equations, analyze a new problem, pitch
>         manure, program a
>         > > computer, cook a tasty meal, fight efficiently, die
>         gallantly.
>         > > Specialization is for insects.
>         > >
>         > > -Robert A. Heinlein
>         >
>         > Add "design a full custom CMOS biosensor IC" to that list.
>         > The little square insect in the middle of the green PCB to
>         the left in
>         >
>         http://pony.noisebridge.net/~cmaier/wearables/hackerspace_meets_academia.jpg
>         > kept me busy enough over the last week that I missed 27C3
>         > (well, at least I didn't end up in an apartment JotWeDe in
>         Berlin with
>         > Leif this end of year).
>         >
>         > For electronics that's actually wearable,
>         > I'm kind of looking for an excuse to try to build some
>         reasonably
>         > standard circuit,
>         > e.g., one with an LTC4060
>         [ http://cds.linear.com/docs/Datasheet/4060f.pdf ]
>         > on some PCB material that is more comfortable to wear than a
>         rigid PCB.
>         > This kind of stuff:
>         >
>         http://ladycartoonist.com/2010/05/soft-circuit-kits-now-for-sale-2/
>         > looks promising,
>         > but I'd need to find a way to find out the design
>         constraints
>         > (minimum trace width, pitch, etc.) and feed them into an EDA
>         program
>         > (default choice at the moment is Altium, for what it's
>         worth),
>         > and have someone either do the sewing or teach me how not to
>         mutilate
>         > myself with a sewing machine and/or serger.
>         >
>         > Eventually, some of these DIY microchips:
>         >
>         http://www.facebook.com/photo.php?pid=31969144&l=6b994e53e9&id=1369525119
>         > should end up in a wearable, dare I think washable, garment.
>         >
>         > But for starters, a wearable charger for one of these
>         slivery things
>         > on the lab bench,
>         > or an antiseptic SEPIC
>         > [ http://www.diodes.com/datasheets/ZXSC380.pdf or some
>         such ]
>         > seems a good project.
>         >
>         > Christoph,
>         > playing postdoc @UCSD
>         > looking for a valid excuse for one of my quarterly
>         noisebridge visits.
>         > _______________________________________________
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>         >
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