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

If red is added, it’ll probably be a complete third channel with multiple LEDs and a brightness range similar to the white modes. Most likely, it’ll be possible to do all functions in red mode, since it’s basically just a different “tint”. However, there might also be a shortcut to red or white from off.

This all depends on whether it actually gets built though. If Sofirn sends me a prototype with a red channel, I’ll make the firmware for it. But I have no idea if that will happen.

Regardless, I’ll probably want to switch the UI to Anduril 2. The basics are the same, but it has all the disco modes and config options blocked by default. Those are only available after unlocking advanced mode. The defaults are much closer to a “normal” flashlight UI, so that hopefully people will be able to use it without reading a manual.

Complete red setup would be great.

One thing that could be improved is the user manual with lines pointing everywhere. Im an ex IT guy and I found it confusing and clustered. A really nice clean “if you want X do X line by line would be an improvement.

I saw the cheat sheet. The fact that there is a cheat sheet makes my case for a re-do.

All that is part of next version and improving whats already an awesome light.

I am going to buy some as xmas gifts.

By the way we are off grid idaho up in the forest. We use 2 lt1s every night for about 5hrs per night on medium setting. The lanterns are using .1v per night. 6 nights in on 1 set batteries 4x3500 and we still have 3.6v remaining. Amazing!

Thanks for an awesome light.

Does anyone know the amp draw of the low and high orange button light? Would it even matter over the 12 days runtime I get?

Crossing my fingers. Having the red LED option would really make this the ultimate camping lantern

I agree but it needs to go low enough too. Just having red isnt great if its 10 lumens at low. I have 3 red heaadlamps and only 1 has 1/4 lumen red which is more light then I want with night adjusted eyes. Maybe 1/8th lumen low and ramp up from there. Remember red is to save night vision and give just enough light to accomplish dark task. In my case 1/4 lumen is the perfect nightlight I can set in the hallway.

Red Camp lantern isn’t to save night vision, a dim white light can do that, ask any pilot. It’s to have light without attracting bugs at the campsite

Most pilots I’ve talked to seem to believe red light is needed to preserve night vision.

As far as I understand the papers I have read on the topic, it is actually for preserving night vision when high enough acuity is needed that white light would alter your night vision. If you just need to see enough to walk around, low intensity white light is better, because it is not color specific. If you need to read, and the scene presents good contrast of white or red and black, red may be better because you can increase the brightness enough to have good acuity without bleaching your rods.

And many animals have very low red sensitivity, so it can also be good for not attracting critters as you say.

Ask me…I am a pilot. We use 1 lumen white to pre-flight and red up in the air while reading maps. Some guys I fly with will preflight with red also. The tarmac and runway lights are blue, not white.

If youve ever flown an airplane on a moonless night over the desert you want all the night vision you can have. VFR of course!

The red LEDs, if they’re added, have the same brightness behavior as the main LEDs.

In other words, the maximum brightness is determined by how many 7135 chips are enabled… and the minimum brightness is about 1/256 of that. So if you set it for a maximum of like 200 lm, the minimum would be about 0.8 lm.

However, red lumens look a lot dimmer than white lumens. So it’ll generally look like less, compared to a white light of the same power level. And since the light goes out in all directions, it’ll look dim compared to a focused beam. The lantern gets something like 0.1 or 0.2 cd/lm, meaning it’s basically a light bulb. An average flashlight makes more like 10 cd/lm, meaning it makes things look about 50 or 100 times as bright with the same amount of photons… because those photons are focused into one place instead of going everywhere.

So I doubt it will have issues with being too bright at the lowest level… except maybe when looking directly at the lantern.

I fly too, albeit single engine land & IFR. The old airplanes I learned in had red overhead lights, but dim white light won’t desensitize the rods either. I’ve flown at night quite a bit, but always file IFR regardless of weather. A mix of colored and white backlighting and dim white cockpit lighting in this airliner. 787 I believe.

Back on track, adding red LED’s to a Camp lantern is a must, for nothing else but to not attract bugs. You’ll still have white light if you live in a bug free desert.

edit: Taxiway lights are blue, runway lights are white. Except for vertical position threshold and end of runway lights

Personally, for the few times I might want to use red light, my Streamlight Siege will do admirably. I wouldn’t buy a second LT1 just to get red capability. But I suppose if someone didn’t yet have a red lantern, a second LT1 might be a great answer.

Ok well I had to read 12000 pages but I was finally able to find an answer.

The orange button has very little drain, ok to leave on high. Can we put a medium orange on the anduril-2?

“ToyKeeper wrote: Phlogiston wrote: ToyKeeper wrote: FWIW, the switch LED has no significant effect on how long the batteries last during standby. Fair enough. I was handwaving: 4×3500mAh cells = 14000mAh 1mA for 14000 hours = about 580 days = about 19 months. What I measured on the Q8 is about 0.1 mA on high, or about 0.03 mA on low. That works out to about 16 years or 53 years of standby time with the button LED constantly on. Anything over a decade is considered negligible since the cell will probably self-discharge faster than that. In any case, I wouldn’t worry about parasitic drain while the lantern is off… even if the button is glowing. Sorted. Real data always trump handwaving ”

Bwahaha……Our type ratings are a bit different. Only landed at runways that required 3 clicks of the mic.

Just reporting back in. Real world off grid battery life.

With factory sofirm 3000mah the lantern ran 8 nights with hours between 4-6hrs every night and medium lumen settings.
With an avg of 5hrs per night thats 40hrs. With a total of 12000mah divided by 40hrs we get 300.

So with 3500mah batteries totalling 14000 divided by 300 gives us 46.6hrs. That would give me 1.5 more nights running.

So 9 or 10 days on medium setting.

Ending voltage was 2.9 blinks.

I will order a matched set of 3500 batteries and report back.

Wish List*
4x5000mah 21700 = 20000mah divided by 300 = 66.6 or 13.3 days runtime.

How critical is it that all 4 be the same type, voltage, resistance?

Even though it’s not recommended, you can use different 18650 batteries with different internal resistance. Concerning different voltages, I see it very critical. Unbalanced voltage of batteries in parallel circuits like in LT1, SP36 or Q8 will result in an instantaneous voltage equalization. Depending on the battery’s internal resistance very high currents will flow between those batteries. If you are lucky and use low drain batteries nothing will happen. If you are unlucky or use high drain batteries, springs will collapse.

In the end, it may look like this...

(picture of an SP36 PCB after running the light with a single Samsung 30Q)

I love this sort of user feedback, thanks for telling us your experience.

Not sure what equipment you have for measuring voltage, but if you charge the cells in the lantern there’s no worry. If you charge them external to the lantern, then charge them to 4.2V, take them out and put them in the lantern. In that scenario, very likely there’s no worry, unless one of your cells is really bad. If you have a meter to measure the voltage, if the readings are within 0.1V there’s likely no problem. More than that, it depends a lot on the cells and such. Lux-Perpetua’s explanation is appropriate for sure. If you don’t have a way to measure the voltage, then just charge the cells.

Just as a point of reference, battery and cell often get used interchangeably, but a single item is called a cell, and one or more cells connected would be a battery. No problem calling a cell a battery, as that’s what most people do.

That would be something, but don’t hold your breath for a LT1 body that can accept 21700 cells

So a 2 week report. Using them on higher mode I get about 4-5 days runtime. I have them hanging in the bathroom and kitchen. They are our main lights. We cook, clean and brush our teeth by these lanterns. It sure would be nice to move the battery meter to the orange on/off button and delay/cancel the main led flash when clicking the button to get your current voltage. Just a small nitpick, nothing big.

Secondly….I want to try running one off 4x21700 batteries. I think the easiest way would be to duct tape a 4pack under bottom of light and run usb cord to port. Try as I might I have been unable to find a 4 slot 21700 holder with/without wires. Any source for that?

Third: I am 100% positive I would like to have this light with a firefly red. I am having to use my headlamps as red nightlights so having a lantern that does it all would be great.

I still love this lantern though. Going to buy some for relatives for xmas.

I’m hoping, if there is ever a LT2, that it will use a tiny1634 chip instead of tiny85… and hopefully it could also use RGB LEDs in the button. That way, it could indicate battery status by color, on the button. This feature already exists on a few other lights, and it basically eliminates the need to ever use the battery check function. Just wait until the indicator gets low enough to turn orange or red, and then recharge.

I will try suggesting the 1634 to Sofirn/Wurkkos anyway to have some more memory for cool features like multiple moonlight levels as Manker demonstrated in their new lights.

Will the 1634 work more accurately in terms of voltage calibration?

I’m not sure if attiny1634 has more accurate voltage or not… but on my personal lights, I have not seen as much variation as with attiny85. Regardless, Anduril 2 has a voltage calibration feature so the user can correct for any variation in the hardware.

About multiple moonlight levels, that isn’t really a MCU thing… it’s determined by the power circuitry. The LT1 has power channels running at about 1750 mA, and it can run those at 256 different levels. So each step is about 6.8 mA apart, and the lowest step is about 6.8 mA.

However, common FET+1 lights use a lowest power channel of 350 mA… and 350 / 256 = 1.3 mA. So they have better resolution at the low end, and work better at moon levels.

The driver could potentially be redesigned completely so it used constant current without PWM… and then it could use 10-bit control instead of 8-bit. This would provide 4X as much resolution, since it’d be 1750 mA / 1024 = 1.7 mA per step, instead of 1750 mA / 256 = 6.8 mA per step. But 4X isn’t a huge increase.

So an even better solution would be to have an even smaller power channel, so it would give even finer resolution. Like, maybe add a 30 mA channel, and then it would have a ~64X increase in resolution (~0.12 mA per step).

However, since the lantern has 2 (or maybe 3) different sets of LEDs, everything needs to be doubled (or tripled). This restricts the driver design quite a bit. Instead of having a low channel and high channel, it would need two low channels and two high channels… and possibly even more if there’s a third set for red. But the control chip can only do PWM on 4 pins. So we could choose between white-only (with finer resolution, 2x2 pins) or white plus red (with the same coarse resolution as the LT1, 1x3 pins).

So… long story short: It’s possible, but complicated.