No idea, I’m just going to wait until it’s complete 
I still need to chip in to his gofundme.
why there is LDO?, isn’t this is 1 cell flashlight?, you could use 2*26350, but it makes no sense to me
and btw, how can you controll current with MCU.
why are people always thinking too much?
a LDO is just a thing that puts out a constant voltage it is not a magical 2S or 4S conversion part
on 2S/4S builds the cell voltage would be above 6V absolute maximum voltage rating of an Attiny MCU, so you need to bring the voltage down (z-diode or LDO)
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totally different story here it remains 1S—>3V driver(could be as well used for 2S—>6V LED)
the LDO is there because it is needed on a CC build
reason:
Attiny MCU puts out a PWM signal, the operation amp needs a DC level
so this PWM signal gets filtered to a DC signal using a low pass
if the MCU voltage is not stabilized then the CC set voltage would vary depending on battery charge(like 2.5A with emtpy battery and 4A with full)
who says you have to build it?
I am developing and building it
when its ready it will be sold
so far I am close to order the prototype of it as design looks good
function got tested on 22mm prototype so it should work
You mean the 2mm WF?
Does it hit ~9A on a low drain (10A rated) 21700?
A local modder here offers FT03’s with the 2mm white flat so I assumed it’s safe for the 2mm.
It is not that simple. A fet driver max output current depends on led forward voltage a lot. An XP-L HI draws like 5A but a 3V XHP50.2 can draw 14A from the same driver. in my L6 a White flat 2mm hit 10A with Liitokala 26650.
Ah, I meant the 1mm on the 5A. Pretty sure people have had 2mm at 10A no probs (as per ZozzV6’s comment).
I needed to lower the turbo because 2mm white flat turned blue at full power.
On those currents you already are beyond max lumens and output is dropping, not healthy for the LED
It is better to stay a bit below max test bench output current and have regulation on a high drain battery not only when it is full
DD is no real option for those ultra low forward voltage emitters
Definitely agree - finding the best regulated output (4.5A?) as a maximum is a good idea. I figure you know what you’re doing, so I’ll just wait patiently 
My tries of white flat 1mm version showed that 4,5A is good for this emitter. Worth the bump from 4A but over that nothing significant output increase happening. Just more heat and turning angry blue over 5A
I thought you were selling blank driver boards… not fully built just wire it up boards!
Definitely buying one!
Why should I sell bare boards?
Without parts you wont be able to equip those easily
Without stencil you cant apply the paste as well to viases
I think that the need for the driver should not be based upon the 1mm flat white plenty of linear drivers for that, but for the 2mm flat white hopfully to get the full potential from the emitter
Or two versions one for 1mm 5A and one for 2mm 9A
1mm 4A is near peak
2mm 7A is near peak
You cant push them as hard than on a test bench as in a flashlight it runs hotter when the head heats up
The goal is to maintain 7A with no heat issues
Sounds good to me, I really dont see any purpose for the 1mm in a light of this size, probably should concentrate on the 2mm flat white.
For people who want to push the WF2 to its limit, I suggest considering that at the very upper level of output, the difference between say 1400 and 1500 lumens, which wouldn’t be noticeable, requires something like 3.5 extra watts to achieve. It is almost pure heat. This effectively causes reduced output due to the light heating up faster and the driver engaging its thermal controls if it has that feature, the cell being depleted faster, and also it is bad for the LED. This is why people who do LED testing often recommend a “sweet spot,” where the output and efficiency are at a reasonable compromise. For me, I’d want to run a WF2 at 5A for something like 1300 lumens. It’s an extra 3W for ~120 lumens from 5 to 6A. I definitely wouldn’t want to go beyond 6A. It’s something like 7 extra watts for ~220 lumens going from 5 to 7 amps. ~30 lumens per watt.
you are absolutely right especially on commercial lights 6A for WF2 should be the maximum
put people want to push them hard, if it dies or degrades replacement is cheap
Its like NOS in a car to boost power for a short amount of time, everyone knows its not healthy, but they still do it
I’m open to whatever people have tested as a good mix of output/heat, so as you’ve both mentioned, there hits a point where the returns just don’t make sense (low lumens/W).
But I know you’ll pick the right level; I have faith