Re: Ridiculously low power LED flasher for science day

"engie" <stephen.english@xxxxxxxxx> wrote in message
news:1151608945.677366.307600@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Hi,
I'm designing an experiment for an electricity themed science day*.
We're going to build super simple motors by coiling some enamled wire,
taking the ends of the coil wire and filing off one side of each end
and sitting this in two stirrups that are connected to a small battery,
with a magnet underneath the coil - you've probably seen the idea
before. These work nicely as motors, and can spin at a fair clip if you
get a nice coil.

I would also like to show that this design works as a (horribly
inefficient low power) generator. As the current generated by this
design is going to be incredibly small, are there any simple, low
component count circuits that could be implemented to store up charge
and discharge it through an LED when there's enough to light it up?

Thanks,
Stephen English
*At SciTech - http://www.scitech.co.uk

If you can find one, (in Australia, I think that Jaycar sell them), an
LM3909 LED flasher IC may be what you need. It will brightly flash a LED
regularly from a 1.5V or slightly lower supply, by using an internal
charge-pump voltage
doubler. A Google search will turn up heaps of results, including the
data*** at:-

http://www1.jaycar.com.au/images_uploaded/LM3909.PDF

.... Humphrey




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