Forever Flasher (& flashlight)

[Ian Stirling]

In sci.electronics.design Ban <bansuri@web.de> wrote:

Ian Stirling wrote:
In sci.electronics.design Ban <bansuri@web.de> wrote:
If I pot a clear epoxy case of the LED in clear eopxy, what does it
do
to the beam pattern?

If you stick that solar cell in clear epoxy it will fail after short
time because of different thermal expansion. (done that, that's why
I say that) Rather take some silicon based potting and glue the
cells on top only. Then use a frame with a plastic or glass inlet to
protect the cheap cells from humidity.

Silicon is a hard substance that is used to make solar cells.

Silicone is a polymer that's used to make everything from flexible
tubing to sex toys.

Are you another self appointed apostrophe inquisitor or what? There is
already one in this group. But maybe in holydays.

Sorry, it's just a pet hate.

thanks for the correction Ban

--
http://inquisitor.i.am/ | mailto:inquisitor@i.am | Ian Stirling.
---------------------------+-------------------------+--------------------------
Things a surgeon should never say:
Better save that for the autopsy.

 

[Tim Williams]

"Ban" <bansuri@web.de> wrote in message
newsXOXa.21531$an6.771485@news1.tin.it...

Are you another self appointed apostrophe inquisitor or what? There is
already one in this group. But maybe in holydays.

Three actually ;-)

Come to think of it, I don't think Ian made the cut..?

Tim

--
In the immortal words of Ned Flanders: "No foot longs!"
Website @ http://webpages.charter.net/dawill/tmoranwms

 

[Lizard Blizzard]

Ban wrote:

Ian Stirling wrote:

In sci.electronics.design Ban <bansuri@web.de> wrote:

If I pot a clear epoxy case of the LED in clear eopxy, what does it
do
to the beam pattern?

If you stick that solar cell in clear epoxy it will fail after short
time because of different thermal expansion. (done that, that's why
I say that) Rather take some silicon based potting and glue the
cells on top only. Then use a frame with a plastic or glass inlet to
protect the cheap cells from humidity.

Silicon is a hard substance that is used to make solar cells.

Silicone is a polymer that's used to make everything from flexible
tubing
to sex toys.


Are you another self appointed apostrophe inquisitor or what? There is
already one in this group. But maybe in holydays.

thanks for the correction Ban

That's me, and Rich Grise. If you don't shape up, you're gonna have to
ship out!


See below.
--
----------------(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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..

 

[Chuck Harris]

Seems to me that all silicone polymers are silicon based, just
as the man said.

-Chuck

Ian Stirling wrote:

I say that) Rather take some silicon based potting and glue the
cells on top only. Then use a frame with a plastic or glass inlet to
protect the cheap cells from humidity.

Silicon is a hard substance that is used to make solar cells.

Silicone is a polymer that's used to make everything from flexible
tubing to sex toys.

Are you another self appointed apostrophe inquisitor or what? There is
already one in this group. But maybe in holydays.


Sorry, it's just a pet hate.



thanks for the correction Ban

 

[Stepan Novotill]

The solar engine illustrates the use of sub-microamp techniques. You
could use it to drive a step-up inductor in place of the motor, or to
gate the V-boost circuit. Feed the solar engine from a small solar
pannel coupled to a tritium light source using clear silicone. (120uH
is correct)

s

On Tue, 5 Aug 2003 01:25:20 -0700, Watson A.Name - 'Watt Sun'
<alondra101@hotmail.com> wrote:

In article <3intivgrhaokccibart732a3gac31ji7ua@4ax.com>,
snovotill@hotmail.com mentioned...
Relevant circuits on my page at http://members.shaw.ca/novotill/
1) LED flasher
2) Solar Engine

...Stepan

Yeah, wacky is the right word. I checked the flickering LED circuit
and it looks like the values for the caps and Rs in the oscs aren't
right. But you _have_ to resave that gawdawfully huge delayed off
switch .PNG to 1024 by 768 size. The 6600 pixels wide is ridiculous!

The solar engine doesn't seem to do anything other than store up and
release the charge in the capacitor. I'm not sure how this would help
my situation.

The LED flasher is a V boost circuit. We've already been thru a few
of those here in ABSE and the other sci.electronics ngs. I checked
that ferrite bead on both Digi-Key's and Mouser's website and it's
just a tiny thing. I can't figure how you could pass that many turns
of even fine wire thru the center hole. The only way I can see how
you'd do it is to wind the wire around the outside like a regular
bobbin. Even then the thing is going to be tiny, with really fine
wires. And I don't believe this has 120 uH inductance (nor 120 mH, as
it says in the text).

Anyhoo, this circuit is kewl for 1.5V stuf, but I've already got 3 or
4V from my solar cell, so no problem. It runs the flasher okay. It's
just a matter of pulling in enough charge from a few minutes in direct
sunlight, where the LED can't be seen, and then once the cap is
charged, bring it inside where it can flash for hours. Or it could be
set near a window to charge up and as the sun sets, it continues to
flash for hours. That's why I need the 1F or so supercap and some
info on how they work in this kind of circuit.

I bought some already wound inductors from Mouser, and they work good
for the inverters I made. It would be easy to just wind a few turns
of #28 or finer wire around the outside of the bobbin of this inductor
to give a feedback tickler coil like the one you made. I like already
assembled coils because of repeatability factors and just plain time
savings.

 

[Chuck Harris]

Stepan Novotill wrote:

The solar engine illustrates the use of sub-microamp techniques. You
could use it to drive a step-up inductor in place of the motor, or to
gate the V-boost circuit. Feed the solar engine from a small solar
pannel coupled to a tritium light source using clear silicone. (120uH
is correct)

That would have to be one hell of a large tritium light source! Tritium
definitely isn't a forever thing. The half life is around 10 years.
That means that in 10 years it will glow half as bright. It would be
far cheaper, safer and more efficient to just use a lithium battery.

-Chuck

 

[Lizard Blizzard]

Chuck Harris wrote:

Stepan Novotill wrote:

The solar engine illustrates the use of sub-microamp techniques. You
could use it to drive a step-up inductor in place of the motor, or to
gate the V-boost circuit. Feed the solar engine from a small solar
pannel coupled to a tritium light source using clear silicone. (120uH
is correct)


That would have to be one hell of a large tritium light source! Tritium
definitely isn't a forever thing. The half life is around 10 years.
That means that in 10 years it will glow half as bright. It would be
far cheaper, safer and more efficient to just use a lithium battery.

Depends on how you look at it. Pessimistic or optimistic. At the
start, you have it put out four times as much light so that in ten
years, it's putting out 'only' twice as much light as needed, and in 20
years it's putting out just as much light as needed. And if you're
still around in 30 years, you'll already be retired and someone else
will get the blame for why it's not working!

Or else just use a free source of thermonuclear radiation, like the OP did!

-Chuck

--
----------------(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
g
h

i
n
c
l
d
u
d
e
d

t
e
x
t

e
r
r
o
r

m
s
g
..

 

[Chuck Harris]

When you are dealing with an amount of tritium that is already
more than 100 times the amount in a well lit watch, multiplying
that amount by 4 times to get 30 years of life is kind of costly.
It would still be better to use a lithium battery.

-Chuck

Lizard Blizzard wrote:

Chuck Harris wrote:



Stepan Novotill wrote:

The solar engine illustrates the use of sub-microamp techniques. You
could use it to drive a step-up inductor in place of the motor, or to
gate the V-boost circuit. Feed the solar engine from a small solar
pannel coupled to a tritium light source using clear silicone. (120uH
is correct)



That would have to be one hell of a large tritium light source! Tritium
definitely isn't a forever thing. The half life is around 10 years.
That means that in 10 years it will glow half as bright. It would be
far cheaper, safer and more efficient to just use a lithium battery.


Depends on how you look at it. Pessimistic or optimistic. At the
start, you have it put out four times as much light so that in ten
years, it's putting out 'only' twice as much light as needed, and in 20
years it's putting out just as much light as needed. And if you're
still around in 30 years, you'll already be retired and someone else
will get the blame for why it's not working!

Or else just use a free source of thermonuclear radiation, like the OP did!

-Chuck

 

[Colubris]

It says:
60 MM SQUARE SOLAR CELL
Output: approximately 3 Volts @ 40 mA. 2.40" square x 0.13" thick
epoxy-encapsulated silicon photovoltaic panel removed from solar
lighting system. Solid, almost-unbreakable module with easy-to-solder
spots on backside. Ideal for solar-powered battery chargers and other
projects.
CAT# SPL-60
Your Price: $3.50 each
These are made of 8 silicon strips connected in series, to give about
3V under load. Like it says, they're in epoxy.

This is an interesting topic - as I'm toying around with a solar
project too.
Is it possible that the surplus dealer is just using "epoxy" as a
general term for "hard, clear, plasticky stuff"?
Wonder if there is some test that can be done to determine what kind
of "epoxy" is being used?

Arch

 

[Kevin McMurtrie]

In article <gTOXa.21516$an6.771073@news1.tin.it>,
"Ban" <bansuri@web.de> wrote:

Watson A.Name - 'Watt Sun' wrote:
In article <OIMXa.20998$an6.751483@news1.tin.it>, bansuri@web.de
mentioned...
If I pot a clear epoxy case of the LED in clear eopxy, what does it
do
to the beam pattern?

If you stick that solar cell in clear epoxy it will fail after short
time because of different thermal expansion. (done that, that's why
I say that) Rather take some silicon based potting and glue the
cells on top only. Then use a frame with a plastic or glass inlet to
protect the cheap cells from humidity.

Now you've _really_ ruined my day! Y'see, the solar cells _already_
come from the factory mounted in clear epoxy! Now what am I gonna do?
Are they going to fail when I put them in the sunlight? :-(

But since they are already coated with epoxy, I can assume that
potting them in an epoxy block will not do any more harm. Am I right?


Are you sure that this is epoxy and not some other more flexible stuff? I
tell you I had some(33) Siemens 6" monocrystalline cells. They were coated
with some whitish epoxy-like material on the back. to combine them i poured
some epoxy mixed with these small glassballs and the hardener only on the
back, the front was a special glass. The assembly worked for one year, but
when left in the hot sun for some time, there were cracks all over the
individual cells, I had to throw everything. :-((
I then inquired and found out about my mistake. The Siemens guy told me that
this coating is really the most difficult part of the game.
I do not know about polycristalline or amorph cells, but the monocrystalline
cells are utterly brittle and damaged easily.
removed irrelevant x-posts
ciao Ban

Those monocrystalline cells are also the best power producers, by far.
I've tried the brown kind and they are mostly useless. Their output
current is low and they have enough leakage that they don't work in low
light.

I'd use clear non-corrosive silicone glue.

 

[Watson A.Name - 'Watt Sun]

In article <bgrm2v$inn$1@bob.news.rcn.net>, cfharris@erols.com
mentioned...

When you are dealing with an amount of tritium that is already
more than 100 times the amount in a well lit watch, multiplying
that amount by 4 times to get 30 years of life is kind of costly.
It would still be better to use a lithium battery.

-Chuck

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.

I've ripped the guts out of a 12V power supply fan, and I can spin it
and light up a small light or LED. Maybe I should put this flasher in
my car window and let the fan spin, and watch it charge up the
supercap.

All I wanna do is convert renewable energy into enough electricity to
power the flasher. If I wanted to have a conversation piece, I'd do
like that guy did with his web server that runs off a potato battery
or whatever it is. http://totl.net/Spud/

Or maybe I would put a heavy weight on a rope that's wound around a
barrel, so that as rope unwinds, the barrel turns a set of gears that
spin a shaft much faster so that it can drive my fan generator. I
would have to 'recharge' my generator by winding the rope up on the
barrel, and lifting the weight. I might be able to get it geared so
that a very havy weight could run it for several hours.

But right now, I've got the flasher working off a solar cell and 6800
uF capacitor for several tens of seconds. I just need it to run for a
lot longer. Like several hours.

Lizard Blizzard wrote:
Chuck Harris wrote:



Stepan Novotill wrote:

The solar engine illustrates the use of sub-microamp techniques. You
could use it to drive a step-up inductor in place of the motor, or to
gate the V-boost circuit. Feed the solar engine from a small solar
pannel coupled to a tritium light source using clear silicone. (120uH
is correct)

That would have to be one hell of a large tritium light source! Tritium
definitely isn't a forever thing. The half life is around 10 years.
That means that in 10 years it will glow half as bright. It would be
far cheaper, safer and more efficient to just use a lithium battery.
[snip]
-Chuck

--
@@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@@

 

[Watson A.Name - 'Watt Sun]

In article <b42cfb8e.0308061622.741ea187@posting.google.com>,
archilochus57@yahoo.com mentioned...

It says:
60 MM SQUARE SOLAR CELL
Output: approximately 3 Volts @ 40 mA. 2.40" square x 0.13" thick
epoxy-encapsulated silicon photovoltaic panel removed from solar
lighting system. Solid, almost-unbreakable module with easy-to-solder
spots on backside. Ideal for solar-powered battery chargers and other
projects.
CAT# SPL-60
Your Price: $3.50 each
These are made of 8 silicon strips connected in series, to give about
3V under load. Like it says, they're in epoxy.

This is an interesting topic - as I'm toying around with a solar
project too.
Is it possible that the surplus dealer is just using "epoxy" as a
general term for "hard, clear, plasticky stuff"?
Wonder if there is some test that can be done to determine what kind
of "epoxy" is being used?

I would speculate that since it is exposed to sunlight that the epoxy
is UV resistant. I've seen some clear plastics turn yellow in
sunlight. Hopefully these won't do that.

All I can say is that the coating is very hard, and looks like clear
epoxy, and I can poke it with a sharp point and it doesn't go in like
softer plastic.

Arch

--
@@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@@

 

[Stepan Novotill]

I now have a circuit that runs off 20 nano-amps. It's easily modified
to flash an LED. See the updated
http://members.shaw.ca/novotill/SolarMotorCircuit.PNG

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.

 

[Ian Stirling]

In sci.electronics.design Colubris <archilochus57@yahoo.com> wrote:

It says:
60 MM SQUARE SOLAR CELL
Output: approximately 3 Volts @ 40 mA. 2.40" square x 0.13" thick
epoxy-encapsulated silicon photovoltaic panel removed from solar
lighting system. Solid, almost-unbreakable module with easy-to-solder
spots on backside. Ideal for solar-powered battery chargers and other
projects.
CAT# SPL-60
Your Price: $3.50 each
These are made of 8 silicon strips connected in series, to give about
3V under load. Like it says, they're in epoxy.

This is an interesting topic - as I'm toying around with a solar
project too.
Is it possible that the surplus dealer is just using "epoxy" as a
general term for "hard, clear, plasticky stuff"?
Wonder if there is some test that can be done to determine what kind
of "epoxy" is being used?

One 'easy' way to avoid the whole issue is to take two sheets of glass.
You glue the back of the cells onto one bit, put blobs of silicone in
between the cells to space the two bits of glass apart, and do it that way.
There is nothing but glass and air between the solar cell and the sun.

--
http://inquisitor.i.am/ | mailto:inquisitor@i.am | Ian Stirling.
---------------------------+-------------------------+--------------------------
"When I use a word," Humpty Dumpty said in a rather scornfull tone, "It means
Just what I choose it to mean - neither more nor less." -- Lewis Carrol

 

[Ian Stirling]

In sci.electronics.design Watson A.Name - 'Watt Sun' <alondra101@hotmail.com> wrote:

In article <bgrm2v$inn$1@bob.news.rcn.net>, cfharris@erols.com
mentioned...
When you are dealing with an amount of tritium that is already
more than 100 times the amount in a well lit watch, multiplying
that amount by 4 times to get 30 years of life is kind of costly.
It would still be better to use a lithium battery.

-Chuck

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.

What does forever mean, and why do you want it?
If I wanted a torch that would work in a thousand years, I'd go
with one of the military batteries that are available with electrolyte
kept seperate from the cell.
Wire a bulb directly to the battery, and when you pour the electrolyte
in, you get light.

Energy storage is a problem.
Nearly all of the non-mechanical methods of storage use electrolytes.
These tend to dry out or corrode things, and fail in a small number of
decades.

Things like silicon transistors, resistors, film capacitors, ...
especially if kept at more or less constant temperature, and not too
hot or with too much power seem to last almost forever.

--
http://inquisitor.i.am/ | mailto:inquisitor@i.am | Ian Stirling.
---------------------------+-------------------------+--------------------------
"The device every conquerer, yes, every altruistic liberator should be required
to wear on his shield... is a little girl and her kitten, at ground zero"
- Sir Dominic Flandry in Poul Andersons 'A Knight of Ghosts and Shadows'

 

[Watson A.Name - 'Watt Sun]

In article <bgt65d$mtf$1$8300dec7@news.demon.co.uk>,
root@mauve.demon.co.uk mentioned...

In sci.electronics.design Watson A.Name - 'Watt Sun' <alondra101@hotmail.com> wrote:
In article <bgrm2v$inn$1@bob.news.rcn.net>, cfharris@erols.com
mentioned...
When you are dealing with an amount of tritium that is already
more than 100 times the amount in a well lit watch, multiplying
that amount by 4 times to get 30 years of life is kind of costly.
It would still be better to use a lithium battery.

-Chuck

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.

What does forever mean, and why do you want it?

Forever is a length of time approaching infinity. I already have it
working without a battery, in other words it will run for its
lifetime, whatever that may be, without replacing the power source.
Maybe if I renamed it "Batteryless Flasher" then I would get people to
forget about the batteries. One concept people can't grasp is that if
I seal this flasher in epoxy, it won't be possible to replace any part
of it in the future. And replacement is what I will have to do if
it's running off batteries.

I already have the flasher running for a time lasting a few tens of
seconds, using a 6800 uF cap. I want to know how long it will run on
much larger supercaps and if the leakage for those caps will be a
substantial amount of the flasher current (~100 microamps average).

If I wanted a torch that would work in a thousand years, I'd go

No, you should say work _for_ a thousand years. That ain't gonna
happen with batteries.

with one of the military batteries that are available with electrolyte
kept seperate from the cell.
Wire a bulb directly to the battery, and when you pour the electrolyte
in, you get light.

Energy storage is a problem.
Nearly all of the non-mechanical methods of storage use electrolytes.
These tend to dry out or corrode things, and fail in a small number of
decades.

Do aerogel carbon supercaps dry out? I know regular electrolytics use
electrolyte (duh) that can leak and corrode, and eventually cause
failure.

Things like silicon transistors, resistors, film capacitors, ...
especially if kept at more or less constant temperature, and not too
hot or with too much power seem to last almost forever.

I have some 1 uF film caps that are about 500 cubic millimeters each.
I need a million for a farad, so that's 500 million cubic millimeters.
That would be a fairly large cube roughly a minimum of .8 meters or
32" on a side. But at a substantial part of a dollar apiece, that's
just a bit over my budget, wouldn't you think?

--
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[Watson A.Name - 'Watt Sun]

In article <01d4jvspuiti1s33ks6d6t0k5c64q4gth9@4ax.com>,
snovotill@hotmail.com mentioned...

I now have a circuit that runs off 20 nano-amps. It's easily modified
to flash an LED. See the updated
http://members.shaw.ca/novotill/SolarMotorCircuit.PNG

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!

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.

--
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Don't be ripped off by the big book dealers. Go to the URL
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[Lizard Blizzard]

Ian Stirling wrote:

[snip]

Why is it wanted to flash, just as a novelty>?

The OP gave the URL of the original circuit, Discover Circuits AKA David
Johnson. http://www.discovercircuits.com/PDF-FILES/3vledfs1.pdf The
original circuit ran off a 150 mAh cell (yes, it was lithium!) for 6
months. The average current is very low, so it will run off a supercap
for a good part of a day. If the LED was full on, at a few mA, that
length of running time would be a matter of minutes, wouldn't you agree?

Do aerogel carbon supercaps dry out? I know regular electrolytics use
electrolyte (duh) that can leak and corrode, and eventually cause
failure.


The makers will probably say no.
However, they do contain electrolyte, and there are none that have been
around 20-30 years.

Here's one way to hedge your bets. Include 4 or 5 supercaps in the
epoxy casting. The flasher itself can use a .22 or a couple .1 uF
ceramic caps so that the possibility of electrolytic failure is not a
problem. Run the leads for the solar cell, flasher and the 4 or 5
supercaps to the surface of the epoxy casting so that they can be
jumpered or un-jumpered if there is a problem with a cap or whatever.
The leads could be surrounded with a thick coating of hot glue or
silicone, so that they could be facing the bottom where they're not
visible, but literally a part of the surface of the casting. If access
is ever needed, a bit of prodding or heat will expose the leads to the
soldering iron. The whole casting would probably be smaller than a pack
of playing cards, so the 'bottom' surface with the silicone could be
covered with dark green felt so it looks like it's the bottom surface.

Voila'! You have a forever flasher, assuming the future inheritor of
this amazing blinky has the ability and knowledge to make a quick change
to a few jumpers.

Ooh! I just had another brainstorm! Imbed a few reed switches inside
the epoxy, connected to the jumpers, and fasten small bar magnets to the
surface with velcro, so they can be moved around. What a cool device -
the fascinated observer could then interact with the device, improving
its gizmo factor. Yeah...

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

 

[Ian Stirling]

In sci.electronics.design Watson A.Name - 'Watt Sun' <alondra101@hotmail.com> wrote:

In article <bgt65d$mtf$1$8300dec7@news.demon.co.uk>,
root@mauve.demon.co.uk mentioned...
In sci.electronics.design Watson A.Name - 'Watt Sun' <alondra101@hotmail.com> wrote:
In article <bgrm2v$inn$1@bob.news.rcn.net>, cfharris@erols.com
mentioned...
When you are dealing with an amount of tritium that is already
more than 100 times the amount in a well lit watch, multiplying
that amount by 4 times to get 30 years of life is kind of costly.
It would still be better to use a lithium battery.

-Chuck

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.

What does forever mean, and why do you want it?

Forever is a length of time approaching infinity. I already have it
working without a battery, in other words it will run for its
lifetime, whatever that may be, without replacing the power source.
Maybe if I renamed it "Batteryless Flasher" then I would get people to
forget about the batteries. One concept people can't grasp is that if
I seal this flasher in epoxy, it won't be possible to replace any part
of it in the future. And replacement is what I will have to do if
it's running off batteries.

Or if a bit fails.
It matters not to the end user if it fails due to a sealed battery
running out, or due to a failure.

Why is it wanted to flash, just as a novelty>?

I already have the flasher running for a time lasting a few tens of
seconds, using a 6800 uF cap. I want to know how long it will run on
much larger supercaps and if the leakage for those caps will be a
substantial amount of the flasher current (~100 microamps average).

If I wanted a torch that would work in a thousand years, I'd go

No, you should say work _for_ a thousand years. That ain't gonna
happen with batteries.

It depends what you want.

Do aerogel carbon supercaps dry out? I know regular electrolytics use
electrolyte (duh) that can leak and corrode, and eventually cause
failure.

The makers will probably say no.
However, they do contain electrolyte, and there are none that have been
around 20-30 years.

Things like silicon transistors, resistors, film capacitors, ...
especially if kept at more or less constant temperature, and not too
hot or with too much power seem to last almost forever.

I have some 1 uF film caps that are about 500 cubic millimeters each.
I need a million for a farad, so that's 500 million cubic millimeters.
That would be a fairly large cube roughly a minimum of .8 meters or
32" on a side. But at a substantial part of a dollar apiece, that's
just a bit over my budget, wouldn't you think?

Not all things are possible in a given way under a budget.
There may be other ways.

--
http://inquisitor.i.am/ | mailto:inquisitor@i.am | Ian Stirling.
---------------------------+-------------------------+--------------------------
To do is to be
To be is to do
Do be do be do do

 

[Chuck Harris]

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.

Further, solar cells degrade with exposure to light. And
tritium is hardly a renewable material, so that suggestion
doesn't cut it either.

Any mechanical gimmick will also break given time. Any plastic
parts will shrink, and cause tolerances to fail, given time.

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.

-Chuck

Watson A.Name - 'Watt Sun' wrote:

In article <bgrm2v$inn$1@bob.news.rcn.net>, cfharris@erols.com
mentioned...

When you are dealing with an amount of tritium that is already
more than 100 times the amount in a well lit watch, multiplying
that amount by 4 times to get 30 years of life is kind of costly.
It would still be better to use a lithium battery.

-Chuck


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.

I've ripped the guts out of a 12V power supply fan, and I can spin it
and light up a small light or LED. Maybe I should put this flasher in
my car window and let the fan spin, and watch it charge up the
supercap.

All I wanna do is convert renewable energy into enough electricity to
power the flasher. If I wanted to have a conversation piece, I'd do
like that guy did with his web server that runs off a potato battery
or whatever it is. http://totl.net/Spud/

Or maybe I would put a heavy weight on a rope that's wound around a
barrel, so that as rope unwinds, the barrel turns a set of gears that
spin a shaft much faster so that it can drive my fan generator. I
would have to 'recharge' my generator by winding the rope up on the
barrel, and lifting the weight. I might be able to get it geared so
that a very havy weight could run it for several hours.

But right now, I've got the flasher working off a solar cell and 6800
uF capacitor for several tens of seconds. I just need it to run for a
lot longer. Like several hours.


Lizard Blizzard wrote:

Chuck Harris wrote:



Stepan Novotill wrote:


The solar engine illustrates the use of sub-microamp techniques. You
could use it to drive a step-up inductor in place of the motor, or to
gate the V-boost circuit. Feed the solar engine from a small solar
pannel coupled to a tritium light source using clear silicone. (120uH
is correct)

That would have to be one hell of a large tritium light source! Tritium
definitely isn't a forever thing. The half life is around 10 years.
That means that in 10 years it will glow half as bright. It would be
far cheaper, safer and more efficient to just use a lithium battery.

[snip]

-Chuck