*BLF LT1 Lantern Project) (updated Nov,17,2020)

DavidEF: I’m not trying to change this design, more just trying to understand why seemingly all BLF lights are based around a FET + 7135(s). I’m a mechanical engineer who has dabbled in electrical engineering in school and work so I’m not an expert. I can just search for buck boost circuits and they look easy enough, but I’m sure I’m missing something. I can understand for turbo output its very cost efficient to use a single fet, but this lantern won’t even be using a fet.

BlueSwordM: I’m not sure I understand your point, as I understand a buck-boost circuit can have a ramping brightness by controlling the voltage output which in turn will control the current with a PID loop. As for color shift it seems that a 4 constant current circuit with 7135s would be very similar in tint for all levels except the 0-25% brightness.

I’m not trying to offer criticism just trying to figure out why the current driver is being used. Is it cost, expertise or something else like performance or durability? Like I said I’m no expert and it may be that I would fail trying to make a buck-boost driver. I have other hobbies so I’ve been a consumer of flashlights so far as I believe I have nothing new to offer, but then I found this place…

@Cpeng, we have 2 sets of LEDs, one with a 3000k CCT, one with a 5000k CCT. That is what makes it much more complicated. We are working to power 4 LEDs at 5000k separately, 3000k LEDs separately, and 8x LEDs at the same time, and we can individually control the power level so we get a desired tint mix color temp.

@BlueSwordM, thanks for information. So you would need 3 separate buck boost drivers to control it, seems you are telling me it wouldn’t be cost effective and or too complicated for this project which is a valid reason. I’m sorry if this is somewhere in the thread. I haven’t had a chance to look through the entire thread.

Edit: I’m an idiot, just searched for “7135” in “search within this thread” and I get the answers I was looking for.

@ Cpeng, definitely not an idiot, you’ve not been around for long and lots has happened over the past couple years of this project. Don’t hesitate to ask questions, most of us are a cordial bunch. I don’t think anyone is being rude, but it may come across that way in text sometimes. Folks are just interested in getting this done and into our hands. I know for one that I could really use this in about a month, but don’t expect it to be ready by then.

3000th thread post :+1: :beer:

Awesome. Would be nice if all new people on BLF figured out this function so quickly. :slight_smile: :+1:

Yeah, I agree. Cpeng, sorry if I was coming off as impatient or rude. We don’t mind you asking questions. :+1:

Yeah I don’t think anyone was being rude, I thought there was a simple answer and there wasn’t. Its better to get responses that I wasn’t expecting rather then no response so I thank everyone for that.

@Cpeng

A reason that is easily overlooked for using a simple and well-tested driver design:

We are developing flashlights in cooperation with a chinese manufacturer (Sofirn) who is halfway around the globe for most of us. We can not pay a visit to check what’s going on, everything must be communicated via the internet through cultural and language barriers, and they are not the most technically advanced flashlight manufacturer around. We chose this manufacturer because they are prepared to work with us and they are able to sell the lantern for the budget price we like to see.

Anything what is new to them is received with reluctance, for them to get used to it takes time, and progress must be meticulously checked by us at every stage because they can knowlingly or by naivety change any detail at any moment, possibly ruining the design. New stuff can always be done, but the process can be made more easy and will speed up by keeping it simple and familiar for them.

Sofirn is accustomed with the type of driver we are now using in the lantern, it is very much like the Q8 driver. It is different in some details (the tint ramping requires some changes in the PCB design) but they understand it and have the components in house. Furthermore, here on BLF is so much knowledge on this type of driver that we can predict pretty well beforehand how it will behave in the lantern, with just some finetuning of the software.

Without knowing details about driver designing, from what I pick up, designing a buck driver is already challenging enough for BLF (but can be done by some of the driver guru’s around) but then it must be prototyped and tested and both the hardware and software finetuned in the lantern. And Sofirn is for sure not able to do much tuning, so for several stages in the design process prototypes must be sent around the world for testing. This is a much longer process, the reward in the end is a better more efficient driver, but only achieved with lots more effort.

I think…

All i am waiting for now is any updates from Barry form his engineers, and if Lexel can build a driver test unit to send Toykeeper to test the firmware on.

I’m mostly just waiting. I’ve done all I can for now.

https://bazaar.launchpad.net/~toykeeper/flashlight-firmware/blf-lantern/files/head:/ToyKeeper/spaghetti-monster/anduril/

Same here. I don’t know if Lexel will build the test driver, but Barry mentioned to me tonight they will need a driver prototype to work on for the lantern.

I’m interested as well. Count me in please.

Jeff

Well said and that makes perfect sense. :+1:

Has there been any progress at all with this project, or is it at a complete standstill?

No ………… yawn……. zzzzzzzz

Compared to the FW3A project, this one is moving at the speed of light. :sunglasses:

also interested, depending on price
will it be able to run on 1/2/3 18650?

Finally I have had the time to read the entire build progress and all I can think is that I love it, and can I please be put on the interest list…?

One thing I didn’t find was pricing ? Probably just missed it.

Thanks for all the hard work DBSAR and to your team as well.

@turbiny, yes, that is the advantage of using 4x18650s in parallel.

You can use 1-4x18650s in the light.

Just don’t put 1-3x fully charged cells with 1 partially discharged cell. Bad things could happen.

As far as price goes, nothing is settled but likely $30-$40 I believe.

Recent additions to the interest list include:
1066 T18
1067 mgracia85
1068 skroober
1069 skroober
1070 Mediocre99
1071 Kame Sennin
1072 asderferjerkel
1073 bmansc
1074 lachesis
1075 Cpeng
1076 bmengineer
1077 jdavis
1078 turbiny

Several more first time posters showing interest in this lantern, including asderferjerkel, Mediocre99, and skroober, as well as turbiny’s second post on BLF. Welcome to BLF :beer:

Note I somehow managed to skip 1066, so I put the last interested person, T18 there.

Master interest list can be accessed by most at the links below:

interest list sorted by entry number

interest list sorted by user names