Lume1-FW3X: Constant Current Buck-Boost & FET Driver with Anduril1/2 + RGB Aux

I’m quoting from the group buy thread, but I think the discussion is more apt for here:

What are your plans for the design after the group buy? Will you just be selling unpopulated boards, or are you considering offering the design either for license or open source publishing? This seems like it could be a good option for some of the custom flashlight manufacturers, who generally use linear + FET drivers.

If the design can be fit in a 17mm footprint (might need to be double-sided?), it should be reasonably easy to adapt to many other lights by sizing the PCB and body contact ring appropriately without re-arranging any of the components.

If the community can also get Bistro working on it, then that can include clicky designs like the Convoy S2+, which is really a great host for a first-time builders. There’s already lots of driver options for that light, but as far as I’ve seen, the buck-boost options tend to have very simple UI’s.

Just put my name down in the interest list.

I’ve skimmed over the pages but I haven’t seen a runtime graph yet… It’ll be nice to see one of those to get some indicator of thermal performance and efficiency.

hi, loneoceans

i don’t know if this was asked before,
are you using toykeepers latest anduril fw3a revision ?
and if there comes an other revision, can we use the original fw3a.hex file to flash this driver ?

sorry is this was a repeat question

Interested in 2. Any color. Hopefully I filled out the interest list comment correctly.

Yo can’t. This is based at Attiny1634 code like Emisar D4V2 and Noctigon K1. Original driver is based on Attiny85 MCU.

ok in that case, if there is a updated Emisar/Noctigon file i could flash that to this driver or it needs to be adapted for for this driver ?

Will the Emisar flashing setup work with this driver?
edit Nevermind, saw on the other thread that it will. Yay!

The hardware is different so firmware will be adapted specially for this driver. One big difference is that will support external temperature sensor. When is released the source code we can see what are the difference between them.

Loneoceans, have you experimented with a boost supply for the purpose of running the LEDs in series rather than parallel? It would be a bit less efficient for power consumption but I think it would be more output efficient in terms of light. One low Vf LED in the 3 or 4 paralleled would hog current from the others is my thought.

AmbientSix, a boost driver would likely be slightly less efficient, as the main size limit is the inductor, which there is not much space for in FW3A.

It would be possible, but would be slightly more complex than Buck-boost, and wouldn’t improve efficiency.

Also, power consumption efficiency is directly proportional to luminous efficacy.

Thanks to everyone; I'm blown away by the support and we definitely have sufficient interest for a run of assembled boards. I'm currently prepping for this.

Answering some recent questions:

  • Yes it wouldn't be too difficult to build variants of the lume1 driver for different flashlights. Like I mentioned, the development cost is quite high since I need to personally purchase the target flashlight, and build at least 1 prototype to validate its functionality. It would be cool to see the lume1 driver in new flashlights to replace the linear ones, but I have no illusions that it'll be a direct replacement since the components and BOM cost necessarily make this a more expensive driver. It could be an upgrade option though, like stainless steel bezels or different material finishes. But this is not up to me to decide, depends on what the manufacturers want!

  • Forsh, yes I'm trying to find some time to make an updated video just to show the different functionalities and AUX LEDs.

  • For the firmware, I branched off the latest Anduril firmware when I was adapting it to fit the lume1 driver. I added some features such as external temperature sensor support etc. I can work with TK to incorporate them in a better way to Anduril with #defines. The idea is for these additional features to be general-use, so they can be easily adjusted in the cfg files when building the .hex. Answering your question directly, no you cannot use the original hex to flash this driver because it uses a ATTINY1634 MCU like the Emisar/Noctigon lights not a TINY85 like the stock driver. However, firmware will be in the BLF firmware repo. lume1 drivers are easily re-flashed using the standard 4:2 pogo-pin programmer, which Notigon sells as well!

  • AmbientSix, yes I have built boost drivers, you can see them in my signature. I agree that running LEDs in parallel directly makes me feel uneasy, precisely for the reasons you mentioned. In practice, the fact that these LEDs are often quite well binned, and they are thermally connected via the MCPCB, and their very high current rating and tempco characteristics allow them to be run in parallel decently, in real life. Same reasoning with the DD FET drive. As one forum member mentioned, this design probably won't get you an A in EE school, but it does work fairly reliably in real life due to a variety of factors.

    That said, I didn't consider building a boost supply since it didn't seem to address the functional requirements for these kind of small multi-LED flashlights. It would be impossible to have a 'direct-drive' mode, for example, and the LEDs are typically not wired in series. Agnelucio is right that the FW3x has very shallow driver cavity, and limits inductor choice. I don't think it'll be any more complex, or significantly different in efficiency, but it just didn't seem like there was a target flashlight for such a driver (at least as far as I know).

I had not thought about the FET direct drive. That is something a lot of us would not sacrifice.

Just a quick post, got around to uploading some photographs of the driver in action with aux LEDs.

I used cyan, pink and warm white LEDs. The above photo shows comparison with the glow gasket in my FW21 flashlight.

I also updated the first post of this thread with more details.

Some vendors who sell 0402 and 0603 LEDs for very low costs:

https://aliexpress.com/store/605870

https://www.aliexpress.com/store/1758868

You can also buy LEDs from digikey, mouser etc, but they typically don't have the 'unusual' colours such as cyan and pink.

Hi loneoceans

What about making a feeler thread for the aux boards, I’d be super interested in at least 2 And if they work perfectly with your driver board , everyone’s a winner

I’d like my fw3 series flashlight , just like the emisar d4v2
Being able to choose what colour aux leds are on

You sir are a genius !
Thank you so much

+1^^^^^^
You can add th to docs spreadsheet.

Looking forward to this. I’ve had to crank the temperature limit up quite high to stop the stock driver from thermal throttling simply due to the driver heating up, rather than the light itself becoming hot. At stock thermal config at top-ramp I was getting almost instant throttling even though the light itself was cold (yes the sensor is calibrated).

With low Vf emitters and a charged high current cell; by my maths there’s about 3W being dissipated in the driver itself at top-ramp, so it gets mighty toasty fast.

The problem with having the temp limit at 70 degrees though is that eventually the light becomes too hot to hold.

Hopefully this driver dissipating <1W in the same circumstances, I can use a sensible thermal limit.

Hello all,

I hope everyone has been well. Here are some new developments for the lume1 project!

Lume1 Driver on Nealsgadgets?

As you may know, I was planning a small 50-100x group order of drivers due to the large interest in the Lume1 driver.

Because of this group order and the interest garnered, Neal from Nealsgadgets has reached out to me and he will be picking up this driver for production. This will likely result in much better prices than this small group order, and also with better shipping / logistics! Discussions and planning are currently underway, so please hang tight. The idea is to be able to purchase these drivers directly from www.nealsgadgets.com, and perhaps also as an option in future flashlights. This also means that the group order will no longer proceed forward, since you should be able to purchase them for better prices too!

The details are still being finalized, and the timeline and other logistics are still being worked out. I will post more detailed updates when they come.

Lume1 Driver Datasheet (Preliminary)

In addition, I managed to get around to document the driver in this datasheet:

https://github.com/loneoceans/lume1-fw3x-anduril/blob/master/LUME1-FW3X%20Datasheet%20-%20PRELIMINARY.pdf

It's still preliminary; once I review it, I'll be able to make an official release. There may be some mistakes in the datasheet, so just be aware!

Finally, thanks everyone for your interest in this project, and for all the support! More to come soon.

the first "production" lights with the Lume1 driver will (hopefully) be the Damascus and Mokume versions of the FW3T

you still can enter the list - but the deposit phase already has begun!
https://budgetlightforum.com/t/-/61844

Mokume Damast

just looked at the datasheet...

very professional!

Wow. Thanks for that awesome documentation!!

Excited to get these in my hands and in some lights!