LED Light for Seasonal Affective Disorder

Discussion in 'Electronic Design' started by D. Lloyd, Nov 14, 2004.

  1. D. Lloyd

    D. Lloyd Guest

    Hi,
    I've been looking at various LED S.A.D. lights available to consumers (eg.
    at www.litebook.com ). They are basically an array of LED's (60 LED's for
    the litebook) that are meant to shine light into your eyes for a period of
    time each day, thus combating the effects of reduced natural light during
    winter months (especially in northern latitudes). However, I just can't
    bring myself to pay $250-$300 U.S. for what is essentially a breadboard with
    a bunch of LED's on it. I know it would cost far less to make it myself.
    Problem is, I don't know that much about electronics. Does anyone know of
    any good sources of information that would help me out with this?

    Thanks
    D. Lloyd
    D. Lloyd, Nov 14, 2004
    #1
  2. D. Lloyd

    Kryten Guest

    I don't see what problem this would solve.

    Fluorescent lights are pretty efficient and cheap.

    LEDs would be more robust and have no mercury, but is it worth the extra
    cost?

    You could simply take the backlight from an old laptop.

    Now if you put just a couple of white LEDs very near the eye (on a glasses
    frame?) you could power them from a battery pack. That would be more
    convenient when travelling on a train :)
    Kryten, Nov 14, 2004
    #2
  3. D. Lloyd

    D. Lloyd Guest

    "Kryten" <> wrote in message
    news:ffPld.604$...
    >I don't see what problem this would solve.


    I don't really have a problem, so to speak. I'm just interested in knowing
    how hard it would be to make my own LED light array.


    > Fluorescent lights are pretty efficient and cheap.


    Yes, flourescent lights are an alternative. However they are quite bulky in
    comparison. I'm looking for something that can sit easily beside my
    computer monitor (on a relatively small desk). As for flourescent SAD
    lights, manufacturers of these lights charge just as much ($200 US and up).
    Go figure.


    > LEDs would be more robust and have no mercury, but is it worth the extra
    > cost?


    LEDs are also small, powerful, energy efficient, and long lasting.


    > You could simply take the backlight from an old laptop.


    I'm not sure what a "backlight" is? I've never used a laptop and don't know
    much about their architecture.


    > Now if you put just a couple of white LEDs very near the eye (on a glasses
    > frame?) you could power them from a battery pack. That would be more
    > convenient when travelling on a train :)


    I've seen a few products like this on the internet. However I've also read
    that they are not as effective. I've never tried them so I'm not sure how
    well they work.
    D. Lloyd, Nov 14, 2004
    #3
  4. D. Lloyd

    Guy Macon Guest

    D. Lloyd wrote:

    >[White] LEDs are also small, powerful, energy efficient, and long lasting.



    32 watt T8 fluorescent -- 85 to 95 lumens/watt

    Standard F40T12 cool white fluorescent--60-65 lumens/watt

    Compact fluorescents -- low 30's to low 60's lumens/watt, typ. 48-60

    T3 tubular halogen -- 20 lumens/watt

    --> White LED -- 15-19 lumens/watt <--

    Standard 100 watt incandescent -- 17 lumens/watt

    Incandescent night light bulb (7w) -- 6 lumens/watt

    Incandescent flashlight bulbs -- dismal, less than 6 lumens/watt

    Source: http://www.otherpower.com/otherpower_lighting.html



    Also see:

    Why LEDs can be 10 times as efficient as incandescents
    in some applications but not in general home lighting
    http://members.misty.com/don/lede.html

    The LED FAQ
    http://www2.whidbey.net/opto/LEDFAQ/The LED FAQ Pages.html

    Don Klipstein's LED Page
    http://members.misty.com/don/ledx.html

    The LED Museum (Note: despite the name, covers the latest LEDs)
    http://www.ledmuseum.org/

    The Unusual Diode FAQ
    http://www.avtechpulse.com/faq.html/

    Wikipedia: Light-emitting diode
    http://en.wikipedia.org/wiki/Light-emitting_diode


    --
    Guy Macon <http://www.guymacon.com>
    Guy Macon, Nov 15, 2004
    #4
  5. "D. Lloyd" <> wrote in message
    news:4197e36b$...
    >
    > "Kryten" <> wrote in message
    > news:ffPld.604$...
    > >I don't see what problem this would solve.

    >
    > I don't really have a problem, so to speak. I'm just interested in

    knowing
    > how hard it would be to make my own LED light array.


    Pretty darn simple
    http://ourworld.compuserve.com/homepages/Bill_Bowden/led.htm
    >
    > > Fluorescent lights are pretty efficient and cheap.

    >
    > Yes, flourescent lights are an alternative. However they are quite bulky

    in
    > comparison. I'm looking for something that can sit easily beside my
    > computer monitor (on a relatively small desk). As for flourescent SAD
    > lights, manufacturers of these lights charge just as much ($200 US and

    up).
    > Go figure.


    Electronic high frequency balast rather than `shop light` balast, gets rid
    of flicker. High colour tempertaure, like daylight and high Colour Rendering
    Index , look for CRI number better than 85. Standard tubes really, just dont
    get sucked into the `full spectrum` nonsense.


    >
    >
    > > LEDs would be more robust and have no mercury, but is it worth the extra
    > > cost?

    >
    > LEDs are also small,


    Yup

    >powerful,


    For their size

    >energy efficient


    Not really fluro is at least twice as efficient


    > and long lasting.


    White declines fairly rapidly, still lights but can be 50% output in as
    little as 2000 hours.


    > > You could simply take the backlight from an old laptop.

    >
    > I'm not sure what a "backlight" is? I've never used a laptop and don't

    know
    > much about their architecture.


    Its the cold cathode lamp that lights the screen, like all LCD screens

    >
    > > Now if you put just a couple of white LEDs very near the eye (on a

    glasses
    > > frame?) you could power them from a battery pack. That would be more
    > > convenient when travelling on a train :)

    >
    > I've seen a few products like this on the internet. However I've also

    read
    > that they are not as effective. I've never tried them so I'm not sure how
    > well they work.


    Fluoro is probably still best, look for high CRI numbers from standard lamp
    makers.

    HTH
    Adam
    Adam Aglionby, Nov 15, 2004
    #5
  6. D. Lloyd

    Kryten Guest

    "D. Lloyd" <> wrote in message
    news:4197e36b$...

    >> Fluorescent lights are pretty efficient and cheap.


    > Yes, fluorescent lights are an alternative.
    > However they are quite bulky in comparison.


    Hmm, I suspect when you add up the number of LEDs needed, they will end up
    being bulky too.

    I'm looking for something that can sit easily beside my
    > computer monitor (on a relatively small desk). As for fluorescent SAD
    > lights, manufacturers of these lights charge just as much ($200 US and
    > up). Go figure.


    I figure they are jerking people off.

    > LEDs are also small, powerful, energy efficient, and long lasting.


    Conventional wisdom says that, but you have to check the figures.

    In most cases they are not as powerful or efficient as filaments or
    fluorescents.

    My bike light is an application where filaments can be beaten.
    The bulb expects 2V5 when loading the 3V battery.
    I use 2V4 NiMH and so the filament tends to run cooler and less efficient.

    I bought a short cold-cathode fluorescent tube and inverter for a few quid,
    and I intend to strap it to my bike as a headlight. How geeky is that? :)

    > I'm not sure what a "backlight" is?


    It is a _light_ source at the _back_ of the LCD in a laptop.
    It is essentially a small cold-cathode fluorescent tube shining into a
    rectangular light-spreader.
    If you look at the tubes directly they are _very_ intense, dazzling the
    retina.
    Should be bright enough!

    > I've seen a few products like this on the internet. However I've also
    > read that they are not as effective. I've never tried them so I'm not
    > sure how well they work.


    Two hypotheses:

    1. The human mind notices the entire scene, not just the light level.
    Even if the total light levels are the same, people will still be depressed
    if they see a grim gloomy grey scene past the bright LED.

    2. The places selling $200 lamps have a vested interest in persuading you
    that a cheap gadget isn't as good.
    Kryten, Nov 15, 2004
    #6
  7. D. Lloyd

    Kim Guest

    I know that this is OT, but a CBC "Venture" program did a documentary on the
    small company that produces pocketbook-sized battery operated LED units for
    seasonal disorders.
    This was about a Engineer, and his wife that worked out of his basement in
    a small town, that designed a small, battery powered unit, as he was tired
    of lugging out his bulky fluorescent unit. This was just when white LEDs
    first came on the scene, and were considered rather exotic, and nobody
    really knew how to deal with them effectively. He designed a battery powered
    unit, with a ton of leds, that worked for a considerable amount of time on
    only a few batteries.
    Every time they had a order, all of their family and friends would have a
    "assembly party" to solder parts on the boards, and assemble the cases.
    Every party would put together a ton of these in their living room, to sell
    all around the world. Their entire house was nothing but boxes, and boxes of
    assembled, and unassembled units. The documentary followed them as they
    visited suppliers of a new design of plastic cases, as they originally
    attempted to get parts locally.
    As I now see them sold quite a bit, I can only assume that they now have
    them assembled in a proper factory, but it was a interesting story of how a
    individual with a good idea, and a lot of hard work created a product. for
    himself, then realised a market for it.
    I saw them recently being sold in a "Hedonics" catalogue.
    Kim


    "Adam Aglionby" <> wrote in message
    news:...
    >
    > "D. Lloyd" <> wrote in message
    > news:4197e36b$...
    > >
    > > "Kryten" <> wrote in message
    > > news:ffPld.604$...
    > > >I don't see what problem this would solve.

    > >
    > > I don't really have a problem, so to speak. I'm just interested in

    > knowing
    > > how hard it would be to make my own LED light array.

    >
    > Pretty darn simple
    > http://ourworld.compuserve.com/homepages/Bill_Bowden/led.htm
    > >
    > > > Fluorescent lights are pretty efficient and cheap.

    > >
    > > Yes, flourescent lights are an alternative. However they are quite

    bulky
    > in
    > > comparison. I'm looking for something that can sit easily beside my
    > > computer monitor (on a relatively small desk). As for flourescent SAD
    > > lights, manufacturers of these lights charge just as much ($200 US and

    > up).
    > > Go figure.

    >
    > Electronic high frequency balast rather than `shop light` balast, gets rid
    > of flicker. High colour tempertaure, like daylight and high Colour

    Rendering
    > Index , look for CRI number better than 85. Standard tubes really, just

    dont
    > get sucked into the `full spectrum` nonsense.
    >
    >
    > >
    > >
    > > > LEDs would be more robust and have no mercury, but is it worth the

    extra
    > > > cost?

    > >
    > > LEDs are also small,

    >
    > Yup
    >
    > >powerful,

    >
    > For their size
    >
    > >energy efficient

    >
    > Not really fluro is at least twice as efficient
    >
    >
    > > and long lasting.

    >
    > White declines fairly rapidly, still lights but can be 50% output in as
    > little as 2000 hours.
    >
    >
    > > > You could simply take the backlight from an old laptop.

    > >
    > > I'm not sure what a "backlight" is? I've never used a laptop and don't

    > know
    > > much about their architecture.

    >
    > Its the cold cathode lamp that lights the screen, like all LCD screens
    >
    > >
    > > > Now if you put just a couple of white LEDs very near the eye (on a

    > glasses
    > > > frame?) you could power them from a battery pack. That would be more
    > > > convenient when travelling on a train :)

    > >
    > > I've seen a few products like this on the internet. However I've also

    > read
    > > that they are not as effective. I've never tried them so I'm not sure

    how
    > > well they work.

    >
    > Fluoro is probably still best, look for high CRI numbers from standard

    lamp
    > makers.
    >
    > HTH
    > Adam
    >
    >
    >
    >
    Kim, Nov 15, 2004
    #7
  8. D. Lloyd

    Kim Guest

    Not the first, or last time that Bill Bowden's EXCELLENT website will be
    mentioned in this forum. Quite substantial, and well designed.
    If I was to ever meet Bill, I would defiantly congratulate him on it.
    Kim


    "Adam Aglionby" <> wrote in message
    news:...
    >
    > "D. Lloyd" <> wrote in message
    > news:4197e36b$...
    > >
    > > "Kryten" <> wrote in message
    > > news:ffPld.604$...
    > > >I don't see what problem this would solve.

    > >
    > > I don't really have a problem, so to speak. I'm just interested in

    > knowing
    > > how hard it would be to make my own LED light array.

    >
    > Pretty darn simple
    > http://ourworld.compuserve.com/homepages/Bill_Bowden/led.htm
    > >
    > > > Fluorescent lights are pretty efficient and cheap.

    > >
    > > Yes, flourescent lights are an alternative. However they are quite

    bulky
    > in
    > > comparison. I'm looking for something that can sit easily beside my
    > > computer monitor (on a relatively small desk). As for flourescent SAD
    > > lights, manufacturers of these lights charge just as much ($200 US and

    > up).
    > > Go figure.

    >
    > Electronic high frequency balast rather than `shop light` balast, gets rid
    > of flicker. High colour tempertaure, like daylight and high Colour

    Rendering
    > Index , look for CRI number better than 85. Standard tubes really, just

    dont
    > get sucked into the `full spectrum` nonsense.
    >
    >
    > >
    > >
    > > > LEDs would be more robust and have no mercury, but is it worth the

    extra
    > > > cost?

    > >
    > > LEDs are also small,

    >
    > Yup
    >
    > >powerful,

    >
    > For their size
    >
    > >energy efficient

    >
    > Not really fluro is at least twice as efficient
    >
    >
    > > and long lasting.

    >
    > White declines fairly rapidly, still lights but can be 50% output in as
    > little as 2000 hours.
    >
    >
    > > > You could simply take the backlight from an old laptop.

    > >
    > > I'm not sure what a "backlight" is? I've never used a laptop and don't

    > know
    > > much about their architecture.

    >
    > Its the cold cathode lamp that lights the screen, like all LCD screens
    >
    > >
    > > > Now if you put just a couple of white LEDs very near the eye (on a

    > glasses
    > > > frame?) you could power them from a battery pack. That would be more
    > > > convenient when travelling on a train :)

    > >
    > > I've seen a few products like this on the internet. However I've also

    > read
    > > that they are not as effective. I've never tried them so I'm not sure

    how
    > > well they work.

    >
    > Fluoro is probably still best, look for high CRI numbers from standard

    lamp
    > makers.
    >
    > HTH
    > Adam
    >
    >
    >
    >
    Kim, Nov 15, 2004
    #8
  9. On Sun, 14 Nov 2004 13:02:13 -0500, D. Lloyd wrote:

    > Hi,
    > I've been looking at various LED S.A.D. lights available to consumers (eg.
    > at www.litebook.com ). They are basically an array of LED's (60 LED's for
    > the litebook) that are meant to shine light into your eyes for a period of
    > time each day, thus combating the effects of reduced natural light during
    > winter months (especially in northern latitudes). However, I just can't
    > bring myself to pay $250-$300 U.S. for what is essentially a breadboard with
    > a bunch of LED's on it. I know it would cost far less to make it myself.
    > Problem is, I don't know that much about electronics. Does anyone know of
    > any good sources of information that would help me out with this?
    >

    Go to the Kitchen Gadgets section of your local grocery or Wally World,
    and get a coffee timer.

    Go to the nearest big department store or so and get a sun lamp.

    Plug the sun lamp into the coffee timer, and set the coffee timer
    for as much light as you want.

    Otherwise, just get a bunch of LEDS, some kind of power supply,
    a handful of resistors, a meter, and go nuts! ;-)

    If you're looking for some kind of goggles that shine flashes of
    light right into your eyeballs a la Ryker's "game" from Raisa,
    then I don't want to have anything to do with you. ;-)

    ;^j
    Rich
    Rich The Philosophizer, Nov 15, 2004
    #9
  10. On Sun, 14 Nov 2004 20:30:03 +0000, Kryten wrote:

    > I don't see what problem this would solve.
    >
    > Fluorescent lights are pretty efficient and cheap.
    >
    > LEDs would be more robust and have no mercury, but is it worth the extra
    > cost?
    >
    > You could simply take the backlight from an old laptop.
    >
    > Now if you put just a couple of white LEDs very near the eye (on a glasses
    > frame?) you could power them from a battery pack. That would be more
    > convenient when travelling on a train :)


    But every time you glom one of those disks, it reinforces the mind
    control programming. It's very insidious, because you think it's only
    stimulating your "pleasure center."

    ;^j
    Rich
    Rich The Philosophizer, Nov 15, 2004
    #10
  11. D. Lloyd

    D. Lloyd Guest

    Many thanks to all who replied and specifically to those who provided LED
    links...guess I'll be doing some reading up.

    D. Lloyd
    D. Lloyd, Nov 15, 2004
    #11
  12. D. Lloyd

    Rich Grise Guest

    On Sun, 14 Nov 2004 17:59:55 -0500, D. Lloyd wrote:
    > "Kryten" <> wrote in message
    >>I don't see what problem this would solve.

    > I don't really have a problem, so to speak. I'm just interested in knowing
    > how hard it would be to make my own LED light array.


    Not "hard" at all. In fact, the actual circuit usually shows up in the
    first few pages of chapter one of any worthwhile electronics tutorial.

    Each LED should have some kind of current-limiting, because it's more
    like a diode than a resistive load - that is, when the voltage reaches
    a certain point, it starts to conduct, and the current increases
    astonishingly rapidly from that point, for surprisingly little change
    in voltage. For a first circuit, this is usually just a series resistor.

    The LED's forward voltage and current ratings will be called out
    _somewhere_, and if you can't find them, you might have to characterize
    a given LED, but usually just "typical" specs will get you well into
    the correct ballpark.
    >
    >> Fluorescent lights are pretty efficient and cheap.

    >
    > Yes, flourescent lights are an alternative. However they are quite bulky in
    > comparison. I'm looking for something that can sit easily beside my
    > computer monitor (on a relatively small desk). As for flourescent SAD
    > lights, manufacturers of these lights charge just as much ($200 US and up).
    > Go figure.
    >

    Just an ordinary desk lamp should do that. They nail you with buzzwords
    like "spectral purity" and "ergonomic" and "natural" and stuff, but it's
    just light.

    Get some red, green, and blue LEDs, learn how to make their brightness
    adjustable (starting with a variable resistor has worked quite well in
    the past :). ), and set the color to whatever suits you.
    >
    >> LEDs would be more robust and have no mercury, but is it worth the extra
    >> cost?

    >
    > LEDs are also small, powerful, energy efficient, and long lasting.


    If you buy those two hundred dollar hooop-te-doos, then no, they're
    not. But if you get a couple of bags of LEDs on ebay for a couple of
    bucks, you can pretty much go as nuts as you want. :)

    >> You could simply take the backlight from an old laptop.

    >
    > I'm not sure what a "backlight" is? I've never used a laptop and don't know
    > much about their architecture.


    Nothing special - it's a flat lamp that lights up the background of the
    LCD screen of laptops. They put one in so you can still play Doom under
    the covers after Mom and Dad are asleep. ;-)
    >
    >> Now if you put just a couple of white LEDs very near the eye (on a glasses
    >> frame?) you could power them from a battery pack. That would be more
    >> convenient when travelling on a train :)

    >
    > I've seen a few products like this on the internet. However I've also read
    > that they are not as effective. I've never tried them so I'm not sure how
    > well they work.


    Heh - Rich the Philosophizer has some ideas on this. As far as Rich the
    Tech, I'd think it'd be terribly counterproductive - it'd be like constant
    glare. I'd rather _hibernate_ than _that_! :)

    Good Luck!
    Rich
    Rich Grise, Nov 15, 2004
    #12
  13. D. Lloyd

    Don Taylor Guest

    "D. Lloyd" <> writes:
    >Many thanks to all who replied and specifically to those who provided LED
    >links...guess I'll be doing some reading up.


    I remember reading things about brightness, wavelength and timing
    of the exposure all being important for lights to be effective in
    combatting SAD. I think that came up when the cheap knock-off
    products started hitting the market, so you might do some reading
    in that area too.
    Don Taylor, Nov 15, 2004
    #13
  14. D. Lloyd

    N. Thornton Guest

    "D. Lloyd" <> wrote in message news:<41983cad$>...
    > Many thanks to all who replied and specifically to those who provided LED
    > links...guess I'll be doing some reading up.
    >
    > D. Lloyd


    just use a halogen light to give you everything you want. LED boxes are a rip off.

    NT
    N. Thornton, Nov 15, 2004
    #14
  15. On Mon, 15 Nov 2004 05:06:49 GMT, in sci.electronics.design Rich The
    Philosophizer <> wrote:

    >On Sun, 14 Nov 2004 13:02:13 -0500, D. Lloyd wrote:
    >
    >> Hi,
    >> I've been looking at various LED S.A.D. lights available to consumers (eg.
    >> at www.litebook.com ). They are basically an array of LED's (60 LED's for
    >> the litebook) that are meant to shine light into your eyes for a period of
    >> time each day, thus combating the effects of reduced natural light during
    >> winter months (especially in northern latitudes). However, I just can't
    >> bring myself to pay $250-$300 U.S. for what is essentially a breadboard with
    >> a bunch of LED's on it. I know it would cost far less to make it myself.
    >> Problem is, I don't know that much about electronics. Does anyone know of
    >> any good sources of information that would help me out with this?
    >>

    >Go to the Kitchen Gadgets section of your local grocery or Wally World,
    >and get a coffee timer.
    >
    >Go to the nearest big department store or so and get a sun lamp.
    >
    >Plug the sun lamp into the coffee timer, and set the coffee timer
    >for as much light as you want.
    >
    >Otherwise, just get a bunch of LEDS, some kind of power supply,
    >a handful of resistors, a meter, and go nuts! ;-)
    >
    >If you're looking for some kind of goggles that shine flashes of
    >light right into your eyeballs a la Ryker's "game" from Raisa,
    >then I don't want to have anything to do with you. ;-)
    >
    >;^j
    >Rich

    I don't remember Ryker's "game" from Raisa, and I cant be bothered to
    goooogle4it

    but from BUPA, probably a respectable site
    http://hcd2.bupa.co.uk/fact_sheets/html/sad.html

    "The light is bright and broad-spectrum, so it is very similar to
    natural daylight "

    So check out the spectrum of day light, get some flouros that simulate
    it



    martin

    It is much easier to make measurements than it is to know
    exactly what you are measuring.

    J.W.N. Sullivan, physicist,
    1928
    martin griffith, Nov 15, 2004
    #15
  16. D. Lloyd

    R.Lewis Guest

    "D. Lloyd" <> wrote in message
    news:41983cad$...
    > Many thanks to all who replied and specifically to those who provided LED
    > links...guess I'll be doing some reading up.
    >
    > D. Lloyd


    If you are looking for a 'broad spectrum' lightsource (just like daylight)
    then white leds are exactly what you are *not* looking for.
    I know nothing about SAD or its therapies but it appears that another
    wonderful tale of the magical properties of leds is looming.
    Someone is bound to suggest that waggling them on and off quickly adds extra
    'powers'.
    R.Lewis, Nov 15, 2004
    #16
  17. D. Lloyd wrote:

    > Many thanks to all who replied and specifically to those who provided LED
    > links...guess I'll be doing some reading up.


    I used to have a link to a site with clinical trial data
    showing that a specific set of blue wavelengths gave the
    best results, and guess what? Yep, you need blue LEDs! Not
    expensive high-output ones either; Radio Shack cheapies work
    just fine.

    Just get a pair of safety goggles (or whatever's cheap,
    handy, and comfortable), hot-glue the LEDs in so that they
    shine into the eyes from above, and add a switch and enough
    other stuff (wire, resistor, batteries+holder) to keep them lit.

    Don't blink them, or run them too bright; what you're
    basically doing is faking the brain into "seeing" blue sky
    overhead. Apparently this simple visible feature of the
    outside world does all sorts of subtle things to hormone
    levels and like that.

    Use the thing only during early morning and late evening,
    when the sun would be up if it weren't winter (or if its
    overcast all day long for those worst afflicted). Slowly
    slide your way into compliance with real time in order to
    wean off them.

    Mark L. Fergerson
    Mark Fergerson, Nov 15, 2004
    #17
  18. Apollo Health has already done the research to determine what
    the best wavelengths are, it turns out to be blue. They
    sell their lightbox at Costco, and they work like magic for both
    SAD and errors in your sleep cycle.

    Best regards
    mark

    R.Lewis wrote:
    > "D. Lloyd" <> wrote in message
    > news:41983cad$...
    >
    >>Many thanks to all who replied and specifically to those who provided LED
    >>links...guess I'll be doing some reading up.
    >>
    >>D. Lloyd

    >
    >
    > If you are looking for a 'broad spectrum' lightsource (just like daylight)
    > then white leds are exactly what you are *not* looking for.
    > I know nothing about SAD or its therapies but it appears that another
    > wonderful tale of the magical properties of leds is looming.
    > Someone is bound to suggest that waggling them on and off quickly adds extra
    > 'powers'.
    >
    >
    >


    --
    ----------------------------------------------------------------------
    Mark W. Lund, PhD ** Battery Chargers
    CEO ** Bulk Cells and Custom Battery Packs
    PowerStream Technology ** Custom Power Supplies
    140 S. Mountainway Drive ** DC/DC Converters
    Orem Utah 84058 ** Custom UPS
    http://www.PowerStream.com ** Engineering, manufacturing, consulting
    Mark W. Lund, PhD, Nov 17, 2004
    #18

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