Many years ago, at some Expo or other, I acquired a flashing plastic
ball that seems rather different from the usual ones I've seen.
(Apparently a promo from RapidMind, which was bought by Intel long ago,
so there's no use going to the source!)

For a start, it's translucent (uncoloured) plastic but perforated,
with the outer holes going all the way through.

I always assumed that like all the others it just had a battery
and a motion sensor plus a chip to control the flashing. After
being tucked away for those many years, though, it no longer
flashed when bounced. I just thought the battery had given out.

However, I was idly bouncing it more extensively a couple of weeks
back, and was astonished to see it flashing again, and getting
brighter the more I bounced it! I deliberately left it alone for
a few days and tried again. Once more the initial flash was dim
or absent and got quite brilliant again after more shocks.

This behaviour is entirely consistent over several repeats, so
I'm wondering if it could possibly be an ultracapacitor and some
kind of piezo charging circuit. The relevant voltages and currents
seem all wrong for this though.

I also have a couple of examples of the more common "Magic Ball"
-- similarly acquired, and also apparently now dead. I cut one
of them apart and found the expected couple of watch batteries
and a spring tremblor. I also found that removing and reinserting
the batteries brought it back to life! (Yes, the contact was
thoroughly corroded.)

The behaviour is different, though. The revitalized ball is always
at full brilliance (though I can't actually bounce it, as it's in
two halves!). I suppose it's conceivable that the mystery ball just
has a corroded battery contact, that somehow becomes more conductive
each bounce, but it's remarkably consistent for that. I do *not*
propose to cut it apart! Too intriguing.

Has anyone else got experience or knowledge of such a beast?

Ta,

-- Pete --

[I somehow get reminded of the "Interocitor" of ancient days... (:-))]

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On Wed, 18 Apr 2018 01:40:09 +0000, Pete wrote:

This behaviour is entirely consistent over several repeats, so I'm
wondering if it could possibly be an ultracapacitor and some kind of
piezo charging circuit. The relevant voltages and currents seem all
wrong for this though.

Most likely it has a magnet and a coil that can generate a lot more
energy than piezo components. There are "eternal" flashlights that have
a free magnet inside a solenoid coil, you shake them to charge a cap.

Also, your ball more likely has an ordinary battery rather than an ultracapacitor.

Jon

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In article <[email protected]>,
Jon Elson <[email protected]> wrote:

On Wed, 18 Apr 2018 01:40:09 +0000, Pete wrote:

This behaviour is entirely consistent over several repeats, so I'm
wondering if it could possibly be an ultracapacitor and some kind of
piezo charging circuit. The relevant voltages and currents seem all
wrong for this though.

Most likely it has a magnet and a coil that can generate a lot more
energy than piezo components. There are "eternal" flashlights that have
a free magnet inside a solenoid coil, you shake them to charge a cap.

Yup -- I have one of those... It lasted about a day! (:-/)
It does have an ultracap, and it seems the designers forgot that such
a beast needs overvoltage protection. A few extra vigorous shakes,
and bye-bye storage! (It still happily lights during the shake itself.)

I don't think there's room inside the ball for any magnet/coil assembly.
The visible module is about 1/2" x 5/8" as best I can see.

Also, your ball more likely has an ordinary battery rather than an >ultracapacitor.

That wouldn't match observed behaviour (unless there's severe leakage
that completely drains the battery after a couple of days). After a
few days' rest, it consistently needs a few thumps to get to full
brightness.

If anyone's interested, I've put images of the thing online at:

http://goodeveca.net/misc/FlashBall.jpg

-- Pete --

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