The tint-adjustable D4v2

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The tint-adjustable D4v2

I needed an excuse to order a D4v2 so I came up with this idea: adjustable tint! This light makes use of 3 different CCT emitters to smoothly adjust tint from 6500K to 2200K roughly along the black body line (within 6 steps).

Since I have to do it with every light, this is also a full MELD implementation with RGB and 365nm UV:

This light uses 3 XP-L2 emitters that are at 6500K, 4000K, and 2200K. Linearly ramping between them gives a color space like this (these are actual measurements I got of the finished light):

The 4000K part ended up being pretty high, which actually benefits the range from 4000K to 2200K for a closer match to BBL.

The electrical design for this is pretty straightforward. The color and UV parts each get a single MEL7135 regulator. The white channel gets 8 of them in parallel to get 2.8A max drive current, and in series with each white emitter is an N-channel FET to allow color adjustment. The 3 FETs for the white emitters are driven with complementary PWM waveforms to set the CCT, and the bank of 7135 regulators are separately PWMed for dimming (at a much lower speed than the FET PWMs).

Fitting all the LEDs in was challenging. I cut traces on the stock LED board to separate the cathodes of each LED footprint, and 3 of the spots were just swapped to my new LEDs. The fourth spot was taken by an XM-L RGBW to pack RGB into the smallest possible space, and this had to be mounted on a small board cut from flex PCB material in order to make the electrical connections accessible. I also had to cut down the dome of the XM-L significantly to get it to fit into the recess in the TIR optic. For the UV part, I shaped a bridge from 0.5mm copper sheet which was soldered to the LED board and the UV part’s thermal pad to provide both mechanical structure and a heatsink. I drilled a hole in the optic to let the UV LED shine directly through the glass (because the plastic blocked 365nm). Since space is at a premium, I also mounted the 3 FETs for the white CCT control on the LED board.

The driver for this light was built completely from scratch using blank 1.6mm PCB material. On the bottom side I cut the copper into concentric rings to make connections for battery positive, white LED combined cathodes, and ground. The 8 MEL7135 regulators are mounted on the bottom:

On the top I left a ring of copper around the outside for ground, and mostly removed the rest of it, leaving tabs to connect Vbat and white cathode. I also milled a slot to give me direct access to the programming header on my microcontroller board.

On the top side I glued down the microcontroller board (small custom breakout for PIC16F1575) and mounted the 4 regulators for the color channels. Then all wires were added:

And I installed the new driver and LED board in the head:

After wiring it up, the hardware was done:

The view from the front looks pretty crazy now:

Because the RGB parts are actually in an optic, the beam pattern on those is pretty good:

I had to spend some time thinking about how to implement CCT control into the MELD UI. I had run into this problem before with my adjustable focus K1, and I wasn’t too happy with how that turned out. This time I took over the color command (click-click-press) and used that to adjust CCT. Color modes are now accessed by triple-click, and the rarely-used strobes are relegated to a second triple-click after going to color modes. This ended up working out pretty well, the CCT adjustment is out of the way enough to only be used when desired, and everything just works as normal once you’ve picked a CCT.

I took some measurements of the finished light to see how the color mixing was performing, and it follows the BBL pretty well. I don’t notice any hue at any point in the range. It gets to about 950 lumens max at 6500K and that drops down to about 700lm at 2200K. Thanks to the parts I got for 4000K, I actually get 90CRI in the middle of the range.

Edit: here’s a quick compilation of build video:

Edited by: tterev3 on 11/24/2020 - 09:26
Tater Tot
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My god.

Amazing work as always.

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Beautiful in so many ways.

Disco party time!

Firelight2's picture
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Amazing work?

When’s the group buy????? Silly

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This is amazing.

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Wow – ambitious project, and incredible work!

id30209's picture
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I hope Hank is seeing this

WTB Titanium 4sevens 2xAA tube

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Fantastic work!

Specialsteve's picture
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Thats it Shocked Thumbs Up

Amazing work!!!

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This is really good!

WVU Tried and True

papastratos_d's picture
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Great stuff. However this modding is not for the faint of heart Big Smile . There is serious science there. Closest I got to tint shifting is Sofirn's offering. Both IF25 (ramping+tintshift, but no Andurill), and also the LT1 lantern. I discovered my love for sub 3000k tint. But also to have higher lumen when needed in the same light...  I hope Hank gets into the tint shifting, with any of the quads but especially 4DSv2 Love


lazerEagle's picture
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RGB on an optic looks rad! Great build.

- the best way to predict the future is to create it -

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That’s super awesome! I hope someone turns this idea into a commercially available product, I would instantly buy that!

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This is excellent, you always do original and super advanced stuff Crown

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This is doper than dope!

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That’s the winner of the the o-l contest right there

never fear shadows…it means a light shines nearby

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Wow! This is just amazing work.

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Added a video of the build process:

MascaratumB's picture
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Shocked Shocked Shocked
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Amazing! Love

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Incredible work. Thank you for the diagrams and in-depth process pictures.

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That is awesome! Thanks for taking us step by step.

Photon Master
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Wow I want to buy this so bad…

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Damm Brother. I hope this gets built.


richbuff said “Sometimes, I feel depressed about my spirit having been cast down to the hostile surface of this one-star planet, without my asking God first, and without God asking me first. I have found that a brief burst of maximum light from what is currently the smallest size flashlight per power makes it all ok/fine for a while, until the next time I feel the need to repeat.”

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Why would you ruin a perfectly good D4v2!!!!

Just kidding, that’s awesome what you did there Smile

I salute you

One Bulb to rule them all,
One Bulb to blind them,
One Bulb to bring them all,
and put the darkness behind them

domasleo's picture
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This is incredible!! Are you willing to sell me one of these drivers/emitter boards? I’m super interested in one!

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domasleo wrote:
Are you willing to sell me one of these drivers/emitter boards?

Making more by hand to sell wouldn’t be feasible for me, but I’d be happy to provide programmed chips with this UI if anyone wants to take a stab at designing their own driver based on my schematic.

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wow, what a great amount of creativity and skill.

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Holy hell..

just when I though I was learning a thing or two about this stuff..

The incredible people like yourself show me how much there is to learn.

Great Work!

Appreciate the ingenious

[FLF] Five Light Friday

Check out some of my new lights (picture heavy) and quick first impressions of them here:

My Sft40 beamshots / comparison thread:

The BLF GT with SFT40 (2300lm, 2700m+ @ 30 seconds!)

Photon Master
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I wonder if you could work with a manufacturer like Hank to produce this light? I’d order it immediately. Amazing!

flightless22's picture
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As always, it’s incredible the meticulous work you do on your mods.

This would be the ultimate EDC for me.