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