Forever Flasher (& flashlight)

[Mark Jones]

Chuck Harris wrote:

Electrolytic capacitors, including the
large 1F kind, tend to be short lived. Since these 1F caps
store their charge thru an electrochemical means, it is really
kind of questionable to call them capacitors.

Is this true? Or do they just use a higher-constant dielectric?

I saw one dielectric that's constant was around 8800, strontium tartanate
or something like that. But I thought capacitors operated on electric-field
(EM) means?

Nevertheless, the only things eternal are death and taxes.

 

[Stepan Novotill]

On Thu, 7 Aug 2003 06:10:40 -0700, Watson A.Name - 'Watt Sun'
<alondra101@hotmail.com> wrote:

But how long do you have to wait between motor operations? At that
rate, it might take a lifetime to move the robot across the room!

WAIT TIME IS DERERMINED BY THE SIZE OF THE CHARGE COLLECTION
CAPACITOR. fOR led APPLICATION THE CAPACITOR WOULD BE SMALL. SINCE WE
DON'T WANT TO DELIVER TOO MUCH POWER TO THE LED.

On Sun, 3 Aug 2003 07:00:41 -0700, Watson A.Name - 'Watt Sun'
alondra101@hotmail.com> wrote:

I built the flasher circuit from Dave Johnson's website, See URL
http://www.discovercircuits.com/PDF-FILES/3vledfs1.pdf
But it just went full on, wouldn't flash. So I had to put a 2.2k from
Q2 base to emitter to get it to flash. I also used two 0.1 uf ceramic
caps instead of rhe 0.68 uF, and the flash rate is right around 1 Hz.
The peak current is 17 mA, and average current is about 100 micromps
at 3V.

I then connected it to a 3V photovoltaic cell and a 1N4148 to prevent
the current from going back into the photocell, and a 6800 uF
capacitor to store the current generated by the light. I put the
photocell directly under a light bulb, and it works fine, and it keeps
working for less than a minute when the light is turned off. So now I
need a lot bigger capacitor, something that will run it for a coupla
hours.

I'm thinking that it would work good using a pair of 1 F, 2.0V
supercaps in series, charged by the photocell.

I bought a Forever Flashlight, the one that has a single white LED,
with a magnet and coil in the barrel that charges up a supercap when
it is shaken. It works, but I'm disappointed in the light output.
The instructions say to shake it for 90 seconds, but even longer than
that gives the LED only a few mA, not a really decent amount. It has
a lens to concentrate the LED's light, so it's better than just the
bare LED alone. Obviously it's meant to be used for situations where
a regular flashlight might not be working, like in an
emergency/earthquake preparedness kit. The body of the flashlight is
clear plastic so I can see the parts inside, and there's a supercap in
there, but the plastic is too thick to see the value, which is
blurred.

So I'm wondering if I should order a couple of these supercaps. The
solar cell is rated for 3V at 40 mA, see the SPL-60 on All Electronics
website, http://www.allelectronics.com/cgi-
bin/category.cgi?category=565&item=SPL-60&type=store
It puts out an honest 4V in bright sunlight, so I would think that it
will charge two 1 F supercaps in series in a few minutes. 3 TCs at 40
mA would be 38 seconds, roughly. Maybe I should try for a couple
farads to keep it running all night long. Has anyone done this
before? Do these supercaps have low enough leakage to stay charged up
for a half a day? After seeing their performance in the 'Forever'
Flashlight, I'm not so sure.

 

[Watson A.Name - 'Watt Sun]

In article <bgu475$fc7$1@bob.news.rcn.net>, cfharris@erols.com
mentioned...
0> That is a laudable goal Watson, but hardly achievable.

Seiko tried to make a watch that used mechanical motion
to charge a capacitor. The problem was the capacitor didn't
last as long as a normal silver oxide cell, and was very
expensive to replace. Electrolytic capacitors, including the
large 1F kind tend to be short lived. Since these 1F caps
store their charge thru an electrochemical means, it is really
kind of questionable to call them capacitors.

I found out about these supercaps by reading this.
www.cooperet.com/pdfs_html/PowerStorGuidelines.pdf

Looks like they are made using an electrolyte. That's not good for a
really long lifetime, but it doesn't mean that they can't last a long
lifetime. As the text says, if the conditions are favorable, their
lifetime will be extended. The conditions that I belive they will be
exposed to will be 3.5VDC, which is at full charge, dropping to less
than 2V as the day goes by. The temperature should be room
temperature, with a bit of warming when exposed to sunlight, which is
only for a few minutes a day. The caps will be sealed in epoxy, so
any leakage from the case will be sealed inside, and can't escape.

Further, solar cells degrade with exposure to light. ...

The sun exposure time could be less than 5 minutes per day. At that
rate, the cells would last more than 70 times longer than a solar cell
exposed to the sunlight all day long. If only a table lamp is used to
charge it, then it might never be exposed to sunlight(!) In either
case, the temperature should stay cool, so that's a big help according
to the document in the URL above.

So, yeah, if you tell your customers that it is a lifetime
blinker, you're going to be lying to them. I'd rather tell
them it is a 20 year blinker, and put a lithium battery in
the puppy.

The way I see it is that with batteries, it's a certainty that they
will have to be replaced, i.e. they are a finite energy source. With
a solar cell and supercaps, they may never have to be replaced, i.e.
they may not last forever, but they may never have to be replaced
during the user's lifetime. With suitable underrating, the forever
flasher may last for a hundred years.

-Chuck
[snip]

Lithium battery is non-renewable.

Am I supposed to lie to people and tell them that this thng will run
forever when it won't? I don't think so.

[snip]

--
@@F@r@o@m@@O@r@a@n@g@e@@C@o@u@n@t@y@,@@C@a@l@,@@w@h@e@r@e@@
###Got a Question about ELECTRONICS? Check HERE First:###
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My email address is whitelisted. *All* email sent to it
goes directly to the trash unless you add NOSPAM in the
Subject: line with other stuff. alondra101 <at> hotmail.com
Don't be ripped off by the big book dealers. Go to the URL
that will give you a choice and save you money(up to half).
http://www.everybookstore.com You'll be glad you did!
Just when you thought you had all this figured out, the gov't
changed it: http://physics.nist.gov/cuu/Units/binary.html
@@t@h@e@@a@f@f@l@u@e@n@t@@m@e@e@t@@t@h@e@@E@f@f@l@u@e@n@t@@

 

[Ban]

Watson A.Name - 'Watt Sun' wrote:

The way I see it is that with batteries, it's a certainty that they
will have to be replaced, i.e. they are a finite energy source. With
a solar cell and supercaps, they may never have to be replaced, i.e.
they may not last forever, but they may never have to be replaced
during the user's lifetime. With suitable underrating, the forever
flasher may last for a hundred years.

Can you tell me what purpose this gadget could be serving?
I have seen (and bought) an optical mouse by Logitech, which had such a
flasher on the package to attract attention, but you go nuts if you work in
that shop where are piled-up lots of these boxes, it even can provoke an
epileptic crisis in certain people, which is the reason they were banned
here in Europe.
Maybe some fixed to a belt for night joggers, well they will need to be more
bright, or if you need to find a light switch at night, what did you have in
mind?

ciao Ban

 

[Watson A.Name - 'Watt Sun]

In article <oFJYa.30525$an6.1074513@news1.tin.it>, bansuri@web.de
mentioned...

Watson A.Name - 'Watt Sun' wrote:

The way I see it is that with batteries, it's a certainty that they
will have to be replaced, i.e. they are a finite energy source. With
a solar cell and supercaps, they may never have to be replaced, i.e.
they may not last forever, but they may never have to be replaced
during the user's lifetime. With suitable underrating, the forever
flasher may last for a hundred years.

Can you tell me what purpose this gadget could be serving?
[snip]
Maybe some fixed to a belt for night joggers, well they will need to be more
bright, or if you need to find a light switch at night, what did you have in
mind?

I've already built it and it's flashing away nicely with the solar
cell under a teble lamp. It's charging up a 6800 uF, 16VDC capacitor,
which is from a package of a dozen that I got at work when Mattel
Intellivision went out of the video game business and donated their
electronics parts to our college in the early '80s. So this
electrolytic cap and the rest of the package are all at least 20 years
old and still working just fine.

I turned off the table lamp and timed the flasher, and it worked for
about 90 seconds from the 6800 uF. I could parallel the other 6800s,
which would give me about 75000 uF, and it should work for maybe a
thousand seconds, which would be about 16 or 17 minutes.

I can get 6.3VDC electrolytic capacitors in the 47,000 to 100,000 uF
range from Mouser or Digi-Key, but paralleling a bunch of those could
cost several tens of dollars and the size would be much, much greater.
Both Elna and PowerStor offer the 1F, 5V supercaps, something like $3
apiece, so they look like a better choice. The size is right, too -
about the size of a lithium button cell with its holder. So a few of
those will fit nicely inside the space of a pack of playing cards.
The solar cell is 2.4" {60 mm) square, so it will be the largest
component. The flasher is smaller than a postage stamp, so it's no
problem. But the capacitors are the one thing on which I haven't made
a decision, so they're an unknown. The solar cell is thin enough so
that the cap or caps might fit underneath, so the PowerStor Aerogel 1
Farad PB-5R0V105 which is 8.5 x 16.8 x 21.5 mm, a bit bigger than a
large crystal can, would fit nicely. Four of those would fit under
the solar cell.

Anyway, I gotta go figure out why the EGR system on my Ford isn't
working right, and fix it or buy some parts. ta..

ciao Ban

--
@@F@r@o@m@@O@r@a@n@g@e@@C@o@u@n@t@y@,@@C@a@l@,@@w@h@e@r@e@@
###Got a Question about ELECTRONICS? Check HERE First:###
http://users.pandora.be/educypedia/electronics/databank.htm
My email address is whitelisted. *All* email sent to it
goes directly to the trash unless you add NOSPAM in the
Subject: line with other stuff. alondra101 <at> hotmail.com
Don't be ripped off by the big book dealers. Go to the URL
that will give you a choice and save you money(up to half).
http://www.everybookstore.com You'll be glad you did!
Just when you thought you had all this figured out, the gov't
changed it: http://physics.nist.gov/cuu/Units/binary.html
@@t@h@e@@a@f@f@l@u@e@n@t@@m@e@e@t@@t@h@e@@E@f@f@l@u@e@n@t@@

 

[Jeff]

"Watson A.Name - 'Watt Sun'" <alondra101@hotmail.com> wrote in message
news:MPG.199cf00447130f20989b72@news.inreach.net...

In article <bgu475$fc7$1@bob.news.rcn.net>, cfharris@erols.com
mentioned...
0> That is a laudable goal Watson, but hardly achievable.
Seiko tried to make a watch that used mechanical motion
to charge a capacitor. The problem was the capacitor didn't
last as long as a normal silver oxide cell, and was very
expensive to replace. Electrolytic capacitors, including the
large 1F kind tend to be short lived. Since these 1F caps
store their charge thru an electrochemical means, it is really
kind of questionable to call them capacitors.

I found out about these supercaps by reading this.
www.cooperet.com/pdfs_html/PowerStorGuidelines.pdf

Looks like they are made using an electrolyte. That's not good for a
really long lifetime, but it doesn't mean that they can't last a long
lifetime. As the text says, if the conditions are favorable, their
lifetime will be extended. The conditions that I belive they will be
exposed to will be 3.5VDC, which is at full charge, dropping to less
than 2V as the day goes by. The temperature should be room
temperature, with a bit of warming when exposed to sunlight, which is
only for a few minutes a day. The caps will be sealed in epoxy, so
any leakage from the case will be sealed inside, and can't escape.

Further, solar cells degrade with exposure to light. ...

The sun exposure time could be less than 5 minutes per day. At that
rate, the cells would last more than 70 times longer than a solar cell
exposed to the sunlight all day long. If only a table lamp is used to
charge it, then it might never be exposed to sunlight(!) In either
case, the temperature should stay cool, so that's a big help according
to the document in the URL above.

From what I have seen of the small large value~ 5V .1F
and up caps, they will outgas, and or leak after time.
I would at least allow a vent hole and maybe some
type of anti-corrosion grease at the connections for
longer life.
Also as they age they (at least some) tend to charge
slower, hours slower and cause ckt loading problems.
Much like batteries.
Jeff

So, yeah, if you tell your customers that it is a lifetime
blinker, you're going to be lying to them. I'd rather tell
them it is a 20 year blinker, and put a lithium battery in
the puppy.

The way I see it is that with batteries, it's a certainty that they
will have to be replaced, i.e. they are a finite energy source. With
a solar cell and supercaps, they may never have to be replaced, i.e.
they may not last forever, but they may never have to be replaced
during the user's lifetime. With suitable underrating, the forever
flasher may last for a hundred years.

-Chuck
[snip]

Lithium battery is non-renewable.

Am I supposed to lie to people and tell them that this thng will run
forever when it won't? I don't think so.

[snip]

--
@@F@r@o@m@@O@r@a@n@g@e@@C@o@u@n@t@y@,@@C@a@l@,@@w@h@e@r@e@@
###Got a Question about ELECTRONICS? Check HERE First:###
http://users.pandora.be/educypedia/electronics/databank.htm
My email address is whitelisted. *All* email sent to it
goes directly to the trash unless you add NOSPAM in the
Subject: line with other stuff. alondra101 <at> hotmail.com
Don't be ripped off by the big book dealers. Go to the URL
that will give you a choice and save you money(up to half).
http://www.everybookstore.com You'll be glad you did!
Just when you thought you had all this figured out, the gov't
changed it: http://physics.nist.gov/cuu/Units/binary.html
@@t@h@e@@a@f@f@l@u@e@n@t@@m@e@e@t@@t@h@e@@E@f@f@l@u@e@n@t@@

 

[Lizard Blizzard]

Jeff wrote:

"Watson A.Name - 'Watt Sun'" <alondra101@hotmail.com> wrote in message
[snip]

I found out about these supercaps by reading this.
www.cooperet.com/pdfs_html/PowerStorGuidelines.pdf
[snip]

From what I have seen of the small large value~ 5V .1F
and up caps, they will outgas, and or leak after time.
I would at least allow a vent hole and maybe some
type of anti-corrosion grease at the connections for
longer life.

So what do you think of this guy's Infini Flasher?
http://tripoint.org/kevtris/Projects/led/flasher.html

He sealed it in a block of resin, with no ill effects so far. The guy
said it's over 5 years old, and still going strong.

--
----------------(from OED Mini-Dictionary)-----------------
PUNCTUATION - Apostrophe
Incorrect uses: (i) the apostrophe must not be used with a plural
where there is no possessive sense, as in ~tea's are served here~;
(ii) there is no such word as ~her's, our's, their's, your's~.

Confusions: it's = it is or it has (not 'belonging to it'); correct
uses are ~it's here~ (= it is here); ~it's gone~ (= it has gone);
but ~the dog wagged its tail~ (no apostrophe).
----------------(For the Apostrophe challenged)----------------
From a fully deputized officer of the Apostrophe Police!

<<Spammers use Weapons of Mass Distraction!>>

I bought some batteries, but they weren't included,
so I had to buy them again.
-- Steven Wright

FOR SALE: Nice parachute: never opened - used once.

F
o
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f
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s
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p
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n
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..

 

[Jeff]

"Lizard Blizzard" <NOSPAM@rsccd.org> wrote in message
news:bh8b0a$3mf3q$1@hades.csu.net...

Jeff wrote:
"Watson A.Name - 'Watt Sun'" <alondra101@hotmail.com> wrote in message
[snip]

I found out about these supercaps by reading this.
www.cooperet.com/pdfs_html/PowerStorGuidelines.pdf
[snip]

From what I have seen of the small large value~ 5V .1F
and up caps, they will outgas, and or leak after time.
I would at least allow a vent hole and maybe some
type of anti-corrosion grease at the connections for
longer life.

So what do you think of this guy's Infini Flasher?
http://tripoint.org/kevtris/Projects/led/flasher.html

He sealed it in a block of resin, with no ill effects so far. The guy
said it's over 5 years old, and still going strong.

There are proably some types that will last longer and

only outgas normally. (never checked which types)
Most of the ones I have seen failed are beyond that,
made in the late 80s or early 90s and some were
newer.
5 years+ may be a long time for a flasher like this but
forever is pushing the envelope.
If I was building for longivity I would want to use parts
that I know will last, if possiable a known life in use, if
not I like overkill but keep it simple.
I like the design.
Jeff

--
----------------(from OED Mini-Dictionary)-----------------
PUNCTUATION - Apostrophe
Incorrect uses: (i) the apostrophe must not be used with a plural
where there is no possessive sense, as in ~tea's are served here~;
(ii) there is no such word as ~her's, our's, their's, your's~.

Confusions: it's = it is or it has (not 'belonging to it'); correct
uses are ~it's here~ (= it is here); ~it's gone~ (= it has gone);
but ~the dog wagged its tail~ (no apostrophe).
----------------(For the Apostrophe challenged)----------------
From a fully deputized officer of the Apostrophe Police!

Spammers use Weapons of Mass Distraction!

I bought some batteries, but they weren't included,
so I had to buy them again.
-- Steven Wright

FOR SALE: Nice parachute: never opened - used once.

F
o
d
d
e
r

f
o
r

s
t
u
p
i
d

n
o
t

e
n
o
u
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i
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c
l
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u
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t
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e
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m
s
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.

 

[Lizard Blizzard]

Jeff wrote:

"Lizard Blizzard" <NOSPAM@rsccd.org> wrote in message
news:bh8b0a$3mf3q$1@hades.csu.net...

Jeff wrote:

"Watson A.Name - 'Watt Sun'" <alondra101@hotmail.com> wrote in message

[snip]


I found out about these supercaps by reading this.
www.cooperet.com/pdfs_html/PowerStorGuidelines.pdf

[snip]


From what I have seen of the small large value~ 5V .1F
and up caps, they will outgas, and or leak after time.
I would at least allow a vent hole and maybe some
type of anti-corrosion grease at the connections for
longer life.

So what do you think of this guy's Infini Flasher?
http://tripoint.org/kevtris/Projects/led/flasher.html

He sealed it in a block of resin, with no ill effects so far. The guy
said it's over 5 years old, and still going strong.


There are proably some types that will last longer and
only outgas normally. (never checked which types)
Most of the ones I have seen failed are beyond that,
made in the late 80s or early 90s and some were
newer.
5 years+ may be a long time for a flasher like this but
forever is pushing the envelope.
If I was building for longivity I would want to use parts
that I know will last, if possiable a known life in use, if
not I like overkill but keep it simple.
I like the design.
Jeff

So what do you suggest for the energy storage element? Using
rechargable batteries? Or a huge bank of non-electrolytic capacitors
that might last a long time without drying out?

Long ago one of the telephone guys told me that the huge lead acid cells
in the central office lasted for thirty years or more. Of course
they're wet cells, with all those nasty chemicals like sulfuric acid.


--
----------------(from OED Mini-Dictionary)-----------------
PUNCTUATION - Apostrophe
Incorrect uses: (i) the apostrophe must not be used with a plural
where there is no possessive sense, as in ~tea's are served here~;
(ii) there is no such word as ~her's, our's, their's, your's~.

Confusions: it's = it is or it has (not 'belonging to it'); correct
uses are ~it's here~ (= it is here); ~it's gone~ (= it has gone);
but ~the dog wagged its tail~ (no apostrophe).
----------------(For the Apostrophe challenged)----------------
From a fully deputized officer of the Apostrophe Police!

<<Spammers use Weapons of Mass Distraction!>>

I bought some batteries, but they weren't included,
so I had to buy them again.
-- Steven Wright

FOR SALE: Nice parachute: never opened - used once.

F
o
d
d
e
r

f
o
r

s
t
u
p
i
d

n
o
t

e
n
o
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..

 

[Jeff]

"Lizard Blizzard" <NOSPAM@rsccd.org> wrote in message
news:bhavha$3musc$1@hades.csu.net...

So what do you suggest for the energy storage element? Using
rechargable batteries? Or a huge bank of non-electrolytic capacitors
that might last a long time without drying out?

I have no idea as of now, neither of the above
would be better.
At least batteries can be replaced with ease but that
kind of defeats the idea.
Some new types may work better and longer but have
not been out long enough to prove it.
Design to last long does not seem to be a very important
consideration anymore.

Long ago one of the telephone guys told me that the huge lead acid cells
in the central office lasted for thirty years or more. Of course
they're wet cells, with all those nasty chemicals like sulfuric acid.

Yea, not something to use for a hand operated device,
can you imagine a parent handing it to a young kid, first
thing you know its in their mouth.... yuck!
And kids love to play with flashlights.
Jeff

--
----------------(from OED Mini-Dictionary)-----------------
PUNCTUATION - Apostrophe
Incorrect uses: (i) the apostrophe must not be used with a plural
where there is no possessive sense, as in ~tea's are served here~;
(ii) there is no such word as ~her's, our's, their's, your's~.

Confusions: it's = it is or it has (not 'belonging to it'); correct
uses are ~it's here~ (= it is here); ~it's gone~ (= it has gone);
but ~the dog wagged its tail~ (no apostrophe).
----------------(For the Apostrophe challenged)----------------
From a fully deputized officer of the Apostrophe Police!

Spammers use Weapons of Mass Distraction!

I bought some batteries, but they weren't included,
so I had to buy them again.
-- Steven Wright

FOR SALE: Nice parachute: never opened - used once.

F
o
d
d
e
r

f
o
r

s
t
u
p
i
d

n
o
t

e
n
o
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i
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c
l
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u
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t
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e
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r
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m
s
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.

 

[Lizard Blizzard]

Jeff wrote:

"Lizard Blizzard" <NOSPAM@rsccd.org> wrote in message
news:bhavha$3musc$1@hades.csu.net...


So what do you suggest for the energy storage element? Using
rechargable batteries? Or a huge bank of non-electrolytic capacitors
that might last a long time without drying out?



I have no idea as of now, neither of the above
would be better.
At least batteries can be replaced with ease but that
kind of defeats the idea.
Some new types may work better and longer but have
not been out long enough to prove it.
Design to last long does not seem to be a very important
consideration anymore.

I really wasn't thinking of replacing the batteries. I was thinking
that with good quality secondary storage cells, the batteries would last
for many, many years, as was the case with the cells in the central
office I mentioned. The storage only has to last less than a day, from
the charging time during the daytime to overnight when it flashes and
discharges.

So with this situation, the better storage choice would seem to be a
large value capacitor.

--
----------------(from OED Mini-Dictionary)-----------------
PUNCTUATION - Apostrophe
Incorrect uses: (i) the apostrophe must not be used with a plural
where there is no possessive sense, as in ~tea's are served here~;
(ii) there is no such word as ~her's, our's, their's, your's~.

Confusions: it's = it is or it has (not 'belonging to it'); correct
uses are ~it's here~ (= it is here); ~it's gone~ (= it has gone);
but ~the dog wagged its tail~ (no apostrophe).
----------------(For the Apostrophe challenged)----------------
From a fully deputized officer of the Apostrophe Police!

<<Spammers use Weapons of Mass Distraction!>>

I bought some batteries, but they weren't included,
so I had to buy them again.
-- Steven Wright

FOR SALE: Nice parachute: never opened - used once.

F
o
d
d
e
r

f
o
r

s
t
u
p
i
d

n
o
t

e
n
o
u
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h

i
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c
l
d
u
d
e
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t
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x
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e
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r
o
r

m
s
g
..

 

[Stepan Novotill]

Apparently a crystal radio receiver with a very long antenna can
supply enough power to run transistor circuits and therefore an LED
using a boost circuit. See:
http://home.t-online.de/home/gollum/dt.htm

Stepan

On Fri, 08 Aug 2003 01:12:47 GMT, Stepan Novotill
<snovotill@hotmail.com> wrote:

On Thu, 7 Aug 2003 06:10:40 -0700, Watson A.Name - 'Watt Sun'
alondra101@hotmail.com> wrote:

But how long do you have to wait between motor operations? At that
rate, it might take a lifetime to move the robot across the room!

WAIT TIME IS DERERMINED BY THE SIZE OF THE CHARGE COLLECTION
CAPACITOR. fOR led APPLICATION THE CAPACITOR WOULD BE SMALL. SINCE WE
DON'T WANT TO DELIVER TOO MUCH POWER TO THE LED.


On Sun, 3 Aug 2003 07:00:41 -0700, Watson A.Name - 'Watt Sun'
alondra101@hotmail.com> wrote:

I built the flasher circuit from Dave Johnson's website, See URL
http://www.discovercircuits.com/PDF-FILES/3vledfs1.pdf
But it just went full on, wouldn't flash. So I had to put a 2.2k from
Q2 base to emitter to get it to flash. I also used two 0.1 uf ceramic
caps instead of rhe 0.68 uF, and the flash rate is right around 1 Hz.
The peak current is 17 mA, and average current is about 100 micromps
at 3V.

I then connected it to a 3V photovoltaic cell and a 1N4148 to prevent
the current from going back into the photocell, and a 6800 uF
capacitor to store the current generated by the light. I put the
photocell directly under a light bulb, and it works fine, and it keeps
working for less than a minute when the light is turned off. So now I
need a lot bigger capacitor, something that will run it for a coupla
hours.

I'm thinking that it would work good using a pair of 1 F, 2.0V
supercaps in series, charged by the photocell.

I bought a Forever Flashlight, the one that has a single white LED,
with a magnet and coil in the barrel that charges up a supercap when
it is shaken. It works, but I'm disappointed in the light output.
The instructions say to shake it for 90 seconds, but even longer than
that gives the LED only a few mA, not a really decent amount. It has
a lens to concentrate the LED's light, so it's better than just the
bare LED alone. Obviously it's meant to be used for situations where
a regular flashlight might not be working, like in an
emergency/earthquake preparedness kit. The body of the flashlight is
clear plastic so I can see the parts inside, and there's a supercap in
there, but the plastic is too thick to see the value, which is
blurred.

So I'm wondering if I should order a couple of these supercaps. The
solar cell is rated for 3V at 40 mA, see the SPL-60 on All Electronics
website, http://www.allelectronics.com/cgi-
bin/category.cgi?category=565&item=SPL-60&type=store
It puts out an honest 4V in bright sunlight, so I would think that it
will charge two 1 F supercaps in series in a few minutes. 3 TCs at 40
mA would be 38 seconds, roughly. Maybe I should try for a couple
farads to keep it running all night long. Has anyone done this
before? Do these supercaps have low enough leakage to stay charged up
for a half a day? After seeing their performance in the 'Forever'
Flashlight, I'm not so sure.

 

[Kevin McMurtrie]

I used to live near an AM radio station. A long wire, an LED, and a
ground was all that was needed.

People who live under high tension power lines could probably drive
several LEDs from two sheets of aluminum foil on their roof


In article <sjulkv8bhot77o9e2lvmjqebvdi4743kso@4ax.com>,
Stepan Novotill <snovotill@hotmail.com> wrote:

Apparently a crystal radio receiver with a very long antenna can
supply enough power to run transistor circuits and therefore an LED
using a boost circuit. See:
http://home.t-online.de/home/gollum/dt.htm

Stepan

On Fri, 08 Aug 2003 01:12:47 GMT, Stepan Novotill
snovotill@hotmail.com> wrote:

On Thu, 7 Aug 2003 06:10:40 -0700, Watson A.Name - 'Watt Sun'
alondra101@hotmail.com> wrote:

But how long do you have to wait between motor operations? At that
rate, it might take a lifetime to move the robot across the room!

WAIT TIME IS DERERMINED BY THE SIZE OF THE CHARGE COLLECTION
CAPACITOR. fOR led APPLICATION THE CAPACITOR WOULD BE SMALL. SINCE WE
DON'T WANT TO DELIVER TOO MUCH POWER TO THE LED.


On Sun, 3 Aug 2003 07:00:41 -0700, Watson A.Name - 'Watt Sun'
alondra101@hotmail.com> wrote:

I built the flasher circuit from Dave Johnson's website, See URL
http://www.discovercircuits.com/PDF-FILES/3vledfs1.pdf
But it just went full on, wouldn't flash. So I had to put a 2.2k from
Q2 base to emitter to get it to flash. I also used two 0.1 uf ceramic
caps instead of rhe 0.68 uF, and the flash rate is right around 1 Hz.
The peak current is 17 mA, and average current is about 100 micromps
at 3V.

I then connected it to a 3V photovoltaic cell and a 1N4148 to prevent
the current from going back into the photocell, and a 6800 uF
capacitor to store the current generated by the light. I put the
photocell directly under a light bulb, and it works fine, and it keeps
working for less than a minute when the light is turned off. So now I
need a lot bigger capacitor, something that will run it for a coupla
hours.

I'm thinking that it would work good using a pair of 1 F, 2.0V
supercaps in series, charged by the photocell.

I bought a Forever Flashlight, the one that has a single white LED,
with a magnet and coil in the barrel that charges up a supercap when
it is shaken. It works, but I'm disappointed in the light output.
The instructions say to shake it for 90 seconds, but even longer than
that gives the LED only a few mA, not a really decent amount. It has
a lens to concentrate the LED's light, so it's better than just the
bare LED alone. Obviously it's meant to be used for situations where
a regular flashlight might not be working, like in an
emergency/earthquake preparedness kit. The body of the flashlight is
clear plastic so I can see the parts inside, and there's a supercap in
there, but the plastic is too thick to see the value, which is
blurred.

So I'm wondering if I should order a couple of these supercaps. The
solar cell is rated for 3V at 40 mA, see the SPL-60 on All Electronics
website, http://www.allelectronics.com/cgi-
bin/category.cgi?category=565&item=SPL-60&type=store
It puts out an honest 4V in bright sunlight, so I would think that it
will charge two 1 F supercaps in series in a few minutes. 3 TCs at 40
mA would be 38 seconds, roughly. Maybe I should try for a couple
farads to keep it running all night long. Has anyone done this
before? Do these supercaps have low enough leakage to stay charged up
for a half a day? After seeing their performance in the 'Forever'
Flashlight, I'm not so sure.

 

[warren weber]

"Kevin McMurtrie" <mcmurtri@dslextreme.com> wrote in message
news:mcmurtri-611539.02170126082003@corp-radius.supernews.com...

I used to live near an AM radio station. A long wire, an LED, and a
ground was all that was needed.

People who live under high tension power lines could probably drive
several LEDs from two sheets of aluminum foil on their roof

How about during a lightning storm? Warren

 

[Lizard Blizzard]

Kevin McMurtrie wrote:

I used to live near an AM radio station. A long wire, an LED, and a
ground was all that was needed.

People who live under high tension power lines could probably drive
several LEDs from two sheets of aluminum foil on their roof

Wow, now that's pretty bizarre. Tin foil caps for a house.

In article <sjulkv8bhot77o9e2lvmjqebvdi4743kso@4ax.com>,
Stepan Novotill <snovotill@hotmail.com> wrote:


Apparently a crystal radio receiver with a very long antenna can
supply enough power to run transistor circuits and therefore an LED
using a boost circuit. See:
http://home.t-online.de/home/gollum/dt.htm

Stepan

[snip]

 

[Stepan Novotill]

A neon bulb between the spokes of an umbrella and the main shaft works
well too, when you are walking under power lines.

Stepan

On Tue, 26 Aug 2003 16:48:22 -0700, Lizard Blizzard <NOSPAM@rsccd.org>
wrote:

Kevin McMurtrie wrote:
I used to live near an AM radio station. A long wire, an LED, and a
ground was all that was needed.

People who live under high tension power lines could probably drive
several LEDs from two sheets of aluminum foil on their roof

Wow, now that's pretty bizarre. Tin foil caps for a house.


In article <sjulkv8bhot77o9e2lvmjqebvdi4743kso@4ax.com>,
Stepan Novotill <snovotill@hotmail.com> wrote:


Apparently a crystal radio receiver with a very long antenna can
supply enough power to run transistor circuits and therefore an LED
using a boost circuit. See:
http://home.t-online.de/home/gollum/dt.htm

Stepan

[snip]

 

[Mark Jones]

Stepan Novotill wrote:

A neon bulb between the spokes of an umbrella and the main
shaft works well too, when you are walking under power lines.

Stepan

On Tue, 26 Aug 2003 16:48:22 -0700, Lizard Blizzard
NOSPAM@rsccd.org> wrote:

Kevin McMurtrie wrote:
I used to live near an AM radio station. A long wire, an
LED, and a ground was all that was needed.

People who live under high tension power lines could
probably drive several LEDs from two sheets of aluminum foil
on their roof

Wow, now that's pretty bizarre. Tin foil caps for a house.

Earlier, I was coming back from lunch at work, and right next door is a
local radio station with two large transmission towers. Lightning was
flashing through the sky, and twice I heard the telltale crackling of
electrostatic ionization... I think the charge must have been jumping across
the insulators used on the guy-wires holding up the towers. First time I
heard it, I shrugged it off. Isn't those things grounded? Second time, I
knew it was coming from the towers.

Brazzzap-crackle-crackle...

 

[Ghost Chip]

Certainly. A power company in northern Arizona sued some indians who ran an
insulated fence along the ground under some high tension transmission lines.
They powered lights from the fence for free
Ghost.

 

[Stepan Novotill]

Some nice tritium light sources that could be coupled to a solar cell
using optical gel.
http://www.roithner-laser.com/tls.htm

A thesis on the conversion of mechanical vibration to electricity.
I suppose this means that the old "sound powered" naval microphones
would work if a step-up transformer is used. Here the thesis:
http://www-mtl.mit.edu/research/icsystems/research/theses/THESIS_raj.PDF

750 millivolt thermopiles, (and 30 millivolt thermocouples)
out of old gas furnaces. A thermopile contains multiple
thermocouples. Could feed a Germanium transistor stepup forward
converter. For example see:
http://www.icca.invensys.com/uniline/c/c84.pdf

You can use a peltier junction array out of a 12volt electric
camping cooler. These seem to have a higher output than most
thermocouples: See this link for an example product that uses a
peltier junction:
http://www.caframo.com/consumer/ecofans/802press.html


On Fri, 29 Aug 2003 19:51:15 -0700, "Ghost Chip" <zoram@cox.net>
wrote:

Certainly. A power company in northern Arizona sued some indians who ran an
insulated fence along the ground under some high tension transmission lines.
They powered lights from the fence for free
Ghost.

 

[Watson A.Name - "Watt Sun]

In article <dcl1lvo2qge69r8a8uecc6vjdc30dd9qjq@4ax.com>,
snovotill@hotmail.com mentioned...
[snip]

750 millivolt thermopiles, (and 30 millivolt thermocouples)
out of old gas furnaces. A thermopile contains multiple
thermocouples. Could feed a Germanium transistor stepup forward
converter. For example see:
http://www.icca.invensys.com/uniline/c/c84.pdf

From what I've read, the thermocouples require a difference in heat to
work. You have to have one end cooled by a heatsink. So part of the
problem is to connect a couple of them in series to get a higher
voltage, but still insulate them so they don't short.

And then there's the problem of getting a hot enough source of heat to
give the needed voltage. I was checking for efficiency and found
this. I assume that this efficiency is more than a standard
thermocouple found in commercial appliances.

RTG Module
Fuel mass 250WT
Voltage 28V
Power 20.5W
Mass 2.2kg
Specific power 9.4W/kg
Thermocouple type Silicon-Germanium
Thermocouple efficiency 7.6%
Number of thermocouples 8
Fuel pile PuO2/Iridium/Graphite


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