Electronic zoomie: adjustable beam in a Noctigon K1

I picked up a K1 super thrower and thought it would make the perfect testbed for an idea I’ve been wanting to try: the electronically-focusable beam. This concept is basically to have a central emitter surrounded by a ring of emitters, set in a reflector, and to adjust the relative outputs of the two groups in order to focus or defocus the beam. To implement this in the K1, I surrounded the stock emitter with a set of 4 XQ-E HI parts of similar color and built a custom driver that can continuously shift the drive power between them. Here’s the result:

While I was at it I also had to add red, green, blue, and UV and put a full MELD user interface in it:

To build the custom LED board, I made an overlay for the stock star out of blank flex PCB material. By carefully cutting away the copper with a hobby knife and leaving the plastic substrate I formed this shape that fits around the stock LED:

And reflowed the new LEDs to it with solder paste:

The added white emitters are XQ-E HI with a similar CCT to the center emitter; the RGB parts are XQ-E HI as well, and the UV is a 390nm Luxeon part. They all share a common anode which is connected by the center ring. I forgot to leave a connection to this ring while cutting it out, so I had to connect to it with some thin enameled wire later. The new LED board is mounted to the stock board with Nitto thermal tape:

Everything was then wired up with 34AWG enameled wire and tested. Being made from flex PCB material, the overlay adds very little to the height and the new LEDs don’t obscure the light from the center emitter.

On to the driver. Unfortunately I don’t have many images of the first part of this - I had previously replaced the microcontroller with one of my own (on a breakout board) to switch the UI to MELD when I first bought the light, so that part was already done. The things to be added this time around are the splitter arrangement for the two white emitter groups, and MEL7135 parts for R, G, B, and UV. I used the same technique of cutting out flex PCB boards and gluing them down (with kapton insulation) to the stock board:

The way the new white channel works is to put a FET in series with each one that can disconnect it from the existing constant-current regulator on the driver. These two FETs are then driven with complementary PWM signals (generated from a CWG peripheral in the microcontroller) such that one of them is always on, and by adjusting the PWM duty cycle I can continuously adjust the balance of current between the two LED groups:

After those FETs were added, I laid down another board that just provides a ground connection and mechanical support for the MEL7135 regulators for the color channels:

And then I installed those and wired everything up:

The opening in the reflector had to be opened up a little bit, and I made a new custom spacer/insulator for the back of it where it contacts the LED board:

It took me a while to work out how to incorporate the beam focus adjustment into the firmware, since all the click/hold combinations are already assigned to other commands. In the end I settled on a double-hold combination where I press-and-hold immediately after ramping brightness. This ended up being easy enough to get to without constantly being activated accidentally. The beam focus adjustment is remembered and everything works as normal after that. I’m now waiting for it to get dark to see what the beam really looks like at long distances. The defocused emitters leave a donut as expected, but the do provide tons of spill as was the goal. I think for a completely practical implementation I would limit the adjustment so that the center emitter never fully turns off, and then you’d be able to adjust the amount of spill without ever leaving a hole in the middle.

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Awesome, and great skills!
Hopefully this will become available from stock in the near future

Wow :open_mouth:

Wonderful. After showing my brother various lights I’ve modified, although i got many compliments his one comment was they don’t zoom. LOL :smiley: need this in my life. Awesome work. i do wonder how much amperage those thin wires can push, great Idea that I’ve only seen in concept but never seen in practice until now.

I wish I had the skill to build my own drivers for projects like this.

This is fantastic! I’m always in awe of your builds! Can’t wait to see the night shots!

Incredible skills!

Your projects never disappoint. Always something crazy (in a good way) and impressive.

Yeah… that’s always an interesting problem to solve, no?

I went with two full clicks followed by a hold… because it was the shortest “hold” which wasn’t taken yet.

Were you able to reuse the reflashing pads with the new MCU?

Very cool to see it pulled off. tterev3, you never fail to impress with the hardest mods out there. I’ve contemplated lights like this but decided they were not good for my needs as they don’t adjust beam width (as long as the outer LEDs are lit) but rather relative brightness at different points of the beam. I much prefer a regular zoomie which gives me perfect flood as well as some throw.

This also reminds me of a somewhat different idea which could have a similar implementation:

Wow. That’s amazing work!