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Subject: Re: Piezo Ignitor to power an LED -- any ideas?
Date: Thu, 21 Nov 2002 16:00:31 GMT
NNTP-Posting-Date: Thu, 21 Nov 2002 11:00:31 EST
Organization: Road Runner
> I've got this half-baked idea to use a piezo ignitor to power an LED
> which needs 2.5v at around 15ma to 20ma. I'm currently under the
> impression that my piezo ignitor and piezo ignitors in general put out
> micro-amperes of power, at around ten thousand volts or more. I'm
> wondering if it's possible to step down the voltage to 2.5v to briefly
> power my LED, or possibly charge a capacitor which will power the LED
> over a short period of time. If it is possible, how would I go about
> doing it?
> I believe a running shoe was manufactured at some point that had
> little flashing LEDs which were powered by a piezo ignition like I'm
> speaking of, but I can't for the life of me remember who made them.
> Thanks in advance for any help.
If you can use a neon instead, that would work quite a bit better. For
the LED, I would imagine that it would take a number of pulses to get a
cap charged enough. The typical LED needs about 1.6V or so, but I would
highly recommend using the super-bright variety, which can require
around 3-ish volts. The benefit would be that it will require only a
fraction of the current of the standard LED to get usable light, so if
this idea has any chance of working, the super-brights will give you a
much better chance. I have lit LED's using typical piezo transducers,
but you need more time for the pulse, or in your case, something to hold
the charge until the voltage reaches some usable level across a cap,
then fire the LED all at once. it's easy to do that, but you may need
some other power to do that detecting/switching, which may defeat your
whole purpose. I have one idea for this now. Here it is:
| D1 ,-------x------. LED
x------(>|-----x-----| some circuit |------(>|----.
| | `--------------' |
| --- |
| ZD1 --- Charge |
R1 | / | Holder cap |
ignitor / |