circuit diagram release

Insomniabuster mk2

12 watts of eye-watering LED emissions!
PTC limited to 1.5A.
LM2575 regulator.

Trying to do this...

Can anybody see issues with this? I'm just trying to make the voltage more discernible for the next stage. It seems to give fixed output though - doesn't vary with change in current (maybe it's still not sensitive enough) :S

Crap... I think I totally forgot about the inverting/non-inverting stuff. Forgotten so much already!

construction update

The regulator circuit seems alright but I want to make sure that it will never push more than 1.5A through the output... do any of you guys have ideas?
On the left is the sensing/bar graph. It seems to lack a bit of precision so I'll have to add in the op-amp to pump up the gain. The output flows through that large white block - a 0.1 ohm resistor - so yeah, the voltage levels are a bit low for the LM3914 comparators to discern.
Sorry about the delays David, just wanting to make sure the LEDs will never be blown up under normal conditions (and even abnormal conditions).

proposed circuit diagram overview

Click to see the whole thing.

Even though the LM2575 has current limiting, I'm wondering whether it's worth putting on extra...

Onwards progress

I have taken shipment of four Cree XP-E blue LEDs.
I'm probably going to use an LM2577 adjustable voltage regulator and then an LM3914 to indicate the power/current magnitude as a row of signal LEDs. While it's not natively current controlled, it allows more user control.

Conversion calculators

Lumen / Lux Calculator
http://www.ledrise.com/shop_content.php?coID=19

Candela to Lumen
http://led.linear1.org/lumen.wiz

Requirements Analysis? (Updateable)

Blue light in 446-477 nm wavelength
PWM for intensity
3000 lux onto 50 cm^2 at approx. 75 cm away

Prelim research: reverse engineering

Product spec pdf

Findings:
Power
12W power = 3*3W LEDs required after efficiency (Power LEDs spread the light evenly)
Array
10*6=60 LEDs, assume 5mm
That's 3.92W assuming 20mA at 3.3V. (Then we'll need to spread the light)

Other:
Lithium Ion cells....
Case.

The goLITE BLU also features a wider field of light than other light boxes, which means that you can work, watch TV, read, or eat meals while using the light box, rather than having to sit close and directly in front of it.

So we'll have to spread the light out.

Power LEDs do seem more cost effective and simpler to deal with.

Power LEDs
http://cutter.com.au/products.php?cat=Cree+XPE
http://cutter.com.au/products.php?cat=Cree+XRE
http://www.dealextreme.com/details.dx/sku.11015
http://www.dealextreme.com/details.dx/sku.13289

5mm LEDs
http://www.dealextreme.com/details.dx/sku.9077

http://www.ledsales.com.au/cart.php?target=category&category_id=43

Maybe someone can do up an analysis on cost/power/performance etc

Prelim questions - ctd

Loose specs:

Sky blue light

3000 lux

Given by The Doctor :)

Tighter specs:

446-477 nm wavelength

3000 Lux ? (LED specs should give us a good idea of how many LEDs we need for the right lux)

Lighting duration ? (need to read more papers)

Dimming/lighting up ? (simulating dusk / dawn)

Directional lighting ? (do we need to worry about that?)

Anything else?

Refer to papers at: http://www.mcsaustralia.com.au/component/content/65.html?task=view

Need to find some more papers to find out the other stuff.

Prelim questions

What wavelength is sky blue? Tolerance/optics...
How much illumination are we aiming for? something that we can measure without buying a luxmeter??

Project Start

Pre-reading:
http://www.mcsaustralia.com.au/products/light-therapy.html

Video at the bottom:
http://www.amazon.com/Philips-goLITE-BLU-Therapy-Device/dp/B001I45XL8

Lux vs Lumen
http://en.wikipedia.org/wiki/Lux
http://www.candlepowerforums.com/vb/showthread.php?t=178086 <- Calculations

Sample DIY
http://www.instructables.com/id/Blue-LED-light-box/

Go-lite manual
http://www.cpapaustralia.com.au/media_files/golite-blu-positioning-gu.pdf

Blue light therapy study:
http://jdc.jefferson.edu/cgi/viewcontent.cgi?article=1002&context=jmbcimfp

LEDs and lighting:

http://green-energy-conservation.blogspot.com/2009/05/led-lighting-basics-and-definitions.html

Retina illumination study:
http://www.ncbi.nlm.nih.gov/pubmed/12568246?dopt=AbstractPlus