Fading the aux LEDs requires software PWM because they are not attached to PWM pins (and probably there wouldn’t be enough PWM channels anyway). Thus the microcontroller would not be able to sleep and would drain the battery fast.
On the D4v2 hardware, it’s not very feasible. It would need three PWM channels to control the three colors, and it doesn’t have that except maybe on the red LED. So without that, it’s limited to only off, low, and high.
However, on hardware designed for smooth color fades, I have a completely different firmware which lets users design their own color patterns. It’s based on the concept of a music synthesizer, where you build sounds (or color patterns) by adding together basic waveforms in various combinations.
The idea is that it drives a lightsaber blade, and each person can have their own custom lightsaber color and pattern. Basically, pick two points in colorspace, set up an oscillation between them, and add another oscillation on top to modify the brightness. It’s fairly simple as far as these things go, but I kept it simple because it’s hard to control a full-featured synth with only one button. Usually those things are covered in knobs.
If you want a gentle but erratic slow green fade, it can do that. If you want an unstable red lightning-ish crackle, it can do that. If you want a rapid shimmer between blueish and reddish purple so it’s hard to even tell what color it is, that’s possible too. Want a blazing orange with a slow white sparkle on top like a sunset? Check. Want it to strobe with alternating red and blue like police sirens? That’s possible too. Or if you want it to make rainbows while spinning the blade in the air, that’s an option.
It shows the changes in real time, so the user basically just has to keep holding or clicking until it looks right, then move on to the next option. It allows people to save up to 12 modes.
Then during use, pressing or holding the button sends it into overdrive so it gets brighter in a momentary sort of way, then fades back to normal. This is useful when doing blade clashes or pretending to deflect blaster shots. And turning it off is intentionally difficult (click, release, hold for 3 seconds), to avoid accidentally doing it in the middle of a battle.
Pardon newbie question, what kind of driver or type of flashlight can accommodate this SyntheSaber UI/firmware?
So far, it only runs on a thing I built myself, using a 4-channel driver Texas_Ace designed.
I’ve been meaning to learn some circuit design tools and redo the layout to make it work better inside a saber hilt, and maybe see if I can get a saber company to make it… but that hasn’t gone well. The lightsaber industry does not have a healthy relationship with its community, so the sort of projects we do at BLF are basically impossible there.
TK, that is pretty darn cool! I am a Star Trek fan, not Star Wars. I was not aware there was a light sabre industry, no doubt if they let you submit a TK designed one… you would rule that firmware world also!
Human women multi-task…
Goddesses Transcend! 
i wonder how hard it would be to place 2 RGB LEDs on the switch PCB and connect them to the AUX LEDs……. 
In some lights, that would be fairly easy. In a D4v2 though, rather tricky. There’s basically no spare room inside, and the switch PCB is barely bigger than the switch itself.
Got a black and a gold D4V2 both XPL-HI 5D 4000k. I love them!
Nice. With those colours, they look like a pair of Duracell flashlights, except they aren’t crap!
I think I posted this somewhere else. It's just what you are compelled to try - if you have two colors.
It’s been done before. See Oshpark Projects - #525 by tterev3
But he uses a completely different driver design, with a different microcontroller. Plus I don’t think it would fit in a D4-sized package. Still something to dream about though. 
Finally got the magnets in after USPS in their infinite wisdom, shipped them all over the country instead of delivering them on Monday like they were supposed to.
The magnets are absolutely perfect! I'd say about 50-60% stronger than the one that came in my D4V2 magnetic tail cap. The original one would hold the light to a magnetic surface but if I bumped it, it would fall off. These new magnets hold pretty firm but not too firm- just right.
Here's the link again if anyone wants to get some.
Is it possible to disable turbo on the d4, basically disabling direct drive?
a true flashaholic would never think such a thought 
Is there firmware avail to support 219b?
The 219c one should be good enough
Afaik, every mode that is drawing more than 350mA of current is using direct drive, so by disabling turbo you won’t disable direct drive. If you want to fully disable turbo(level 150) I guess the only option is the muggle mode(6 clicks when the light is off to enable it, 6 clicks when the light is off to disable it). If you just want to use the light in regulated mode(no direct drive), you can configure the ramping mode ceiling, this won’t disable the turbo mode, but your highest level in ramping mode will be in the regulated range. While the light is on in a ramping mode click 4 times to enter the ramp config mode, then to configure ramp ceiling wait for the light to blink 2 times and rapidly flicker(buzz), then click 82 times, this will set the ceiling level to 69, which is probably the highest regulated level, actually it should be around 70 but due to the inaccuracy of calculations it is better to set 69 or even 68).
But for the exact level it is better to ask ToyKeeper, because there is also a possibility that steps scale in the stepped ramp is nonlinear and the value 70 was calculated from the fact that step 4 in the stepped ramp with default settings is the highest regulated mode.
It isn’t possible to disable it completely, but you can set the maximum to whatever level you want. The light will not ramp above that level. (You can still get to turbo using the double-click shortcut when the light is on.)