From: Chuck Simmons
Organization: You jest.
X-Mailer: Mozilla 4.61 [en] (X11; U; Linux 2.0.33 i586)
Subject: Re: Piezo Ignitor to power an LED -- any ideas?
Date: Thu, 21 Nov 2002 15:25:50 GMT
NNTP-Posting-Date: Thu, 21 Nov 2002 07:25:50 PST
> On Thu, 21 Nov 2002 14:15:16 GMT, Kevin McMurtrie
> >In article <firstname.lastname@example.org>,
> > J81 wrote:
> >>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.
> >A piezo ignitor will not power an LED or anything else. The total power
> >released from the hammer's strike is too low.
> >It's hard to find data on the blinking shoes. I suspect they use a
> >lithium battery but it could be generated.
> Do you happen to know a good way for me to test the output power of
> the ignitor, given that I anticipate it being at 10,000 volts or more?
> See, I thought that the output power would be about one micro-ampere;
> 0.000001A. According to the rough education I have when it comes to
> transformers, stepping 10,000 volts down to 10 volts should increase
> the amperage up to .001A, or 1 milliamp. Dropping the voltage down
> even further, to 1 volt, should grant me 10 milliamps, no? 10ma at 1v
> should be enough to get at least some light from an LED, I would
> I lack hard data on the behavior of a piezo ignitor and what the
> absolute minimum time period, current, and voltage would be, which is
> why I bring my question here. Being able to test the output of my
> piezo ignitor would be extremely helpful.
The piezoignitor is a capacitor. If you connect it's output to a larger
capacitor, you will get a lower voltage that you might be able to
measure with a high impedance voltmeter or electrometer. The voltage
tells you how much energy you have by E=V^2*C where E is energy in
joules, V is voltage in volts and C is capacitance in farads.
... The times have been,
That, when the brains were out,
the man would die. ... Macbeth
Chuck Simmons email@example.com