How about a link to that circuit for us Spelunkers :)

-----Original Message-----
From: Olin Lathrop [mailto:olin_piclist@EMBEDINC.COM]
Sent: Wednesday, July 09, 2003 2:59 PM
To: PICLIST@MITVMA.MIT.EDU
Subject: Re: [EE]: New! One Cell Switching Regulator Schematics


> BTW, is there a design to pulse drive at least two white LEDs from a
> single 1.5v cell ?

I was playing with that last weekend.  I was actually trying to drive a
string of 4 white LEDs, which requires about 13V.  I did get it to work
from a little over 1V, but the efficiency wasn't very good.  I also =
didn't
like the relatively high cutout voltage compared to what a NiMH battery
can do.  In the end I decided to go with 2 cells.  This will be able to
function even with rechargeable batteries until they are well drained.

I intend the batteries, switch, and most of the circuit to go on the =
back
of a hat, with the LEDs clipped to the visor.  Two rechargeable AA cells
isn't that bad for over 9 hours of continuous light.  All the =
electronics
are packed onto a 2.5 x 2.1 inch circuit board, using all thru hole
components.


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