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Faraday Flashlight...

X

Xtrchessreal

Jan 1, 1970
0
You have seen the commercials on TV about the new flash light that
never dies and needs no batteries?

Anyone here have one?

I don't have one but I was wondering about the bulb. It seems likely
that it is a led or two or three.

I figure the thing is a coil with a magnet passing through to induce a
current with a small transformer to turn the current into a high
voltage whose energy is stored in a large electrolytic capacitor. The
capacitor is discharged slowly over a resistor and the led/diode in
series.

Not a bad design but I can't believe the light from it is any better
than my penlight brinkman. Anyone have one to compare notes with?

Moving parts will cause something to breakdown quickly if your son
starts playing with it like a toy - which it basically is right? Good
toy for the child engineering type perhaps.
 
R

Ryan

Jan 1, 1970
0
Xtrchessreal said:
You have seen the commercials on TV about the new flash light that
never dies and needs no batteries?

Anyone here have one?

I think I know the commercial you are talking about. I don't have the
same light officially, but basically, the one I have is the same. I
have the smaller version of a shake flashlight, translucent clear
plastic.

Stock, mine came with two CR2032 coin batteries. Cheating, right? I
took those out to see how long it really lasts. Usually these lights
come with some form of high capacitance capacitor, either 0.47 farad
or 1.0 farad.

After several seconds of pretty hard shaking, mine charges fully. The
LED (only one) is full bright for about 6 seconds and then I would say
it is half bright for about 2 minutes. It gets dimmer and dimmer more
and more slowly after that.

I can use it around the house to dodge toys and stuff during those few
minutes. It wouldn't be of much use outside, for example.

You have to shake it just a little bit hard than you prefer in order
to make enough voltage to charge.

I paid $4.00 for it (non retail) so I don't mind for having learned
about it.

I also have a 3 LED crank-up light. This one is much more useful.
Inside this one is not a capacitor, but a lithium (ion?) battery.
About a minute of pretty good cranking (at least two revolutions per
second) yields maybe 5 minutes of pretty good light. The first two
minutes or so are pretty good and then it is noticably dimmer but
still useful. You can read a book with it for maybe 10-15 minutes,
depending on who you are.

This one uses 3 gears of speed increase from the handle and powers a
small DC motor. Actually, I think it is a stepper motor? There is a
bridge rectifier inside and you can crank either way.

-Ryan
 
S

steamer

Jan 1, 1970
0
--Think about it: "Farad" is a unit of capacitance. Rattle a magnet
thru a coil and you charge up a capacitor. Cap drains and makes flashlight
bulb light up; that's all it is. Oh, and they *do* wear out..
 
S

Si Ballenger

Jan 1, 1970
0
I think I know the commercial you are talking about. I don't have the
same light officially, but basically, the one I have is the same. I
have the smaller version of a shake flashlight, translucent clear
plastic.

Stock, mine came with two CR2032 coin batteries. Cheating, right? I
took those out to see how long it really lasts. Usually these lights
come with some form of high capacitance capacitor, either 0.47 farad
or 1.0 farad.

After several seconds of pretty hard shaking, mine charges fully. The
LED (only one) is full bright for about 6 seconds and then I would say
it is half bright for about 2 minutes. It gets dimmer and dimmer more
and more slowly after that.

I can use it around the house to dodge toys and stuff during those few
minutes. It wouldn't be of much use outside, for example.

You have to shake it just a little bit hard than you prefer in order
to make enough voltage to charge.

I paid $4.00 for it (non retail) so I don't mind for having learned
about it.

I also have a 3 LED crank-up light. This one is much more useful.
Inside this one is not a capacitor, but a lithium (ion?) battery.
About a minute of pretty good cranking (at least two revolutions per
second) yields maybe 5 minutes of pretty good light. The first two
minutes or so are pretty good and then it is noticably dimmer but
still useful. You can read a book with it for maybe 10-15 minutes,
depending on who you are.

This one uses 3 gears of speed increase from the handle and powers a
small DC motor. Actually, I think it is a stepper motor? There is a
bridge rectifier inside and you can crank either way.

-Ryan

I've got one of the origional Russian "forever flashlight" like
below. Switching to LEDs would probably make it a little more
functional. Would be interesting to test the new pumper light
(bottom) against the shaker lights.

http://members.aol.com/townslight/pumper.htm
http://theepicenter.com/hand_powered_items.html
 
R

Rich Grise, but drunk

Jan 1, 1970
0
I've got one of the origional Russian "forever flashlight" like below.
Switching to LEDs would probably make it a little more functional. Would
be interesting to test the new pumper light (bottom) against the shaker
lights.

http://members.aol.com/townslight/pumper.htm
http://theepicenter.com/hand_powered_items.html

Do they go, "Whirrrrr" when you pump them?

Illuminate your cave and exercise your grip simultaneously! ;-P

I'm kinda thinking, an aluminum or SCH40 PVC tube, with one of
these inside:
http://www.magnetsource.com/Solutions_Pages/cowmags.html
and as many turns of #36 ~ 40 wire as you can fit; a couple
of spongy rubbery pads at the ends, and maybe a supercap -
I haven't thought it through that far yet. ["No Shit, Sherlock!"
-- One of my other pesky homunculi]

Thanks!
RIch
 
M

Mark Fergerson

Jan 1, 1970
0
Xtrchessreal said:
You have seen the commercials on TV about the new flash light that
never dies and needs no batteries?

Anyone here have one?

Yep, they were discussed nearly to death on SED recently.
I don't have one but I was wondering about the bulb. It seems likely
that it is a led or two or three.

One, yellowish-white.
I figure the thing is a coil with a magnet passing through to induce a
current with a small transformer to turn the current into a high
voltage whose energy is stored in a large electrolytic capacitor. The
capacitor is discharged slowly over a resistor and the led/diode in
series.

Pretty much. Magnet, coil, four diodes, .47F supercap, limiting diode
and LED.
Not a bad design but I can't believe the light from it is any better
than my penlight brinkman. Anyone have one to compare notes with?

Bright as hell for the first ten minutes, bright enough to see
clearly across the street. Unusable for reading large print at about
twenty minutes, but usable for navigating large obstacles for thirty.
Moving parts will cause something to breakdown quickly if your son
starts playing with it like a toy - which it basically is right? Good
toy for the child engineering type perhaps.

I got two for US$5 at Wallgreen's. Had two CR3032 coin batteries
which it works just fine without per Ryan's reply, though mine seem to
be brighter and last longer than his. These are clones of clones of the
"Forever Flashlight" as seen on TV mind you, and others on SED reported
buying fakes with magnets that weren't, coils connected to nothing, and
bogus circuit boards.

As for moving parts, the magnet bangs into fairly robust rubber
bumpers at both ends of its travel, but the switch is made of thin, not
very springy zinc-plated steel which had to be rebent in one of the pair
I got before it would come on.

BTW one survived the "four-foot drop to a concrete floor" test (quite
accidentally) with no damage or failure.

Overall, I trust 'em. One is in my toolbox, the other in my wife's
nightstand.


Mark L. Fergerson

PS keep the magnets away from any magnetic media you don't want scrambled!
 
B

Bill Bowden

Jan 1, 1970
0
You have seen the commercials on TV about the
new flash light that never dies and needs no
batteries?
Anyone here have one?

Yes, I got mine from Santa Claus. It's the large version, about a foot
long with dual coils, rechargable lithium battery, and runs for 10
hours on a 10 minute shake. I haven't timed it to see if the
advertising is true, but it runs for a long time on a short shake. It
has a single white LED that is very bright at 2 or 3 feet. It's a bit
bulky, weighs almost a pound, and won't fit in your pocket. The magnet
is strong enough to pick up a 7 ounce pair of pliers.

-Bill
 
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