[Noisebridge-discuss] driving multiple LEDs with minimal batteries

Jake jake at spaz.org
Wed Jan 5 19:49:31 UTC 2011

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.

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.

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.


---- original mess ----

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 
this EE stuff. Could some kind person point me in the right direction?

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