LED Light for Seasonal Affective Disorder

[D. Lloyd]

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

 

[Kryten]

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

 

[Guy Macon]

D. Lloyd wrote:

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%20LED%20FAQ%20Pages.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>

 

[Kim]

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" <nws@capersville.co.uk> wrote in message
news:2vqdhuF2pa0o8U1@uni-berlin.de...

"D. Lloyd" <lloydda@nowhere.com> wrote in message
news:4197e36b$1@news.nnrp.ca...

"Kryten" <kryten_droid_obfusticator@ntlworld.com> wrote in message
news:ffPld.604$IM1.414@newsfe4-gui.ntli.net...
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

 

[Rich The Philosophizer]

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]

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

 

[D. Lloyd]

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

D. Lloyd

 

[Rich Grise]

On Sun, 14 Nov 2004 17:59:55 -0500, D. Lloyd wrote:

"Kryten" <kryten_droid_obfusticator@ntlworld.com> 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

 

[Don Taylor]

"D. Lloyd" <lloydda@nowhere.com> 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.

 

[N. Thornton]

"D. Lloyd" <lloydda@nowhere.com> wrote in message news:<41983cad$1@news.nnrp.ca>...

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

 

[R.Lewis]

"D. Lloyd" <lloydda@nowhere.com> wrote in message
news:41983cad$1@news.nnrp.ca...

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 Fergerson]

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

 

[D. Lloyd]

"Kryten" <kryten_droid_obfusticator@ntlworld.com> wrote in message
news:ffPld.604$IM1.414@newsfe4-gui.ntli.net...

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.

 

[Kim]

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" <nws@capersville.co.uk> wrote in message
news:2vqdhuF2pa0o8U1@uni-berlin.de...

"D. Lloyd" <lloydda@nowhere.com> wrote in message
news:4197e36b$1@news.nnrp.ca...

"Kryten" <kryten_droid_obfusticator@ntlworld.com> wrote in message
news:ffPld.604$IM1.414@newsfe4-gui.ntli.net...
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

 

[Kryten]

"D. Lloyd" <lloydda@nowhere.com> wrote in message
news:4197e36b$1@news.nnrp.ca...

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.

 

[Mark W. Lund, PhD]

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" <lloydda@nowhere.com> wrote in message
news:41983cad$1@news.nnrp.ca...

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