[Noisebridge-discuss] driving multiple LEDs with minimal batteries

miloh froggytoad at gmail.com
Wed Jan 5 12:16:25 PST 2011


On Wed, Jan 5, 2011 at 11:49 AM, Jake <jake at spaz.org> wrote:
> There was a guy who came to Circuit Hacking Mondays who made these tiny
> circuitboards with a Linear Technologies chip that boosted power from a
> low voltage to up to 30 volts with a set current limit.  He brought them
> to CHM as a kit i think, and was making umbrellas with hanging lights.
>
> Mitch or Miloh will know who i'm speaking of.  He was really tall and thin
> and older than Miloh...
>
> anyway the great awesomeness of his kit is like this:  you hook up a
> battery to it (a single AA, rechargable or not) or a lithium-whatever, it
> doesn't care - and it will work.
>

yah this is the 'lumbrella' I mentioned above...
PIC
http://www.tokyostation.com/photos/lumbrella/lumbrella-pic-560.jpg

And the recent workshop on building the compact SMD board:
https://www.noisebridge.net/pipermail/noisebridge-discuss/2010-October/017336.html

> On the output side, you simply wire all your LEDs in series - one after
> another, any colors, no resistors necessary - and the thing will power
> them all with the same current.  Regardless of the state of the battery
> (until it is empty)  Up to 30v or 10-15 LEDs in series per board.
>


That's a better way to describe it, I tried to keep it simple with the
'white leds' example above.

> I think the appropriate way to power a scarf is with a single AA sized
> battery.  People can use a disposable battery but a rechargable AA is
> ubiquitous and appropriate, and an be charged separately from the scarf.
> And a scarf is something that will hopefully outlast any LiFePo battery or
> NiMH cell, so it has to be a standard, replaceable cell like a AA.
>

exactly.  I really feel this is the award-winning solution here,
unless your scarf comes with a docking station!


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