Texas_Ace BLF Calibrated Lumen tube / Sphere No math skills needed - Several spheres still available

Well that’s very annoying. If you were to make more in the future I’d recommend charging a non refundable deposit for the cost of the parts.

I’ll share this around and see if there’s interest. I wish someone would make me a sphere, but the shipping to NZ wouldn’t be cheap

He had something unavoidable come up that caused him to cancel, I do not blame him at all, I would of done the same thing. I would of refunded any deposit under the circumstances anyways lol.

Mostly trying to clean some stuff up and tax time just hit me harder then expected, so could use some extra cash.

I’ll take one!

How often does it need to be recalibrated? Is there data logging capability with the meter?

Basically never IF you don’t change anything. I purchased calibration lights from maukka and it was only out by 4 ish lumens from memory.

You’d need to purchase another meter for data logging or just use a phone app like me

You can use a phone, but if you can swing roughly $100 to $150 for a used data logger, get that. Much easier to use and if you get a calibrated one it will be more accurate.

Make sure you calibrate it with lights with honest factory ratings (Nightwatch, thrunite, Olight, Rovyvon, Fenix, Speras are pretty trustworthy).

I’m interested in the 3.5”. Can you tell me if the 3.5 version work with the Noctigon K1? The head measures 2.84”.

Affirmative, it’ll fit up to 89mm, but you’ll need to make your own discs. I just use cardboard and reflective tape

Excellent, thanks. I’ll PM TexasAce.

Actually, the largest disc is 76mm, so you won’t need to make one for the K1 at only 72mm.

Even better, thanks!

As was stated, unless something happens, it should not need to be re-calibrated. Mine that is ~5 years old still reads within ~5 lumens.

It does get dusty over time though, so I have to clean it out, if I don’t then the readings will start dropping.

Yep, also like Funtastic said, it will fit no problem.

If you have a light that is odd sized custom discs can be made out of cardboard as well.

My version has stayed the same without need for re-cal.
Like +/- 2 Lumens on a 1000 Lumen light. And maybe it’s the light that changed, not the tube?

Unless I fuss with it - then all bets are off. My version can be re-calibrated easily because of the design.
Any mod will make a difference. Just let it be, and it should be consistent.

Watch out for changes in room lighting. Keep it constant over time.
A few lumens can sneak into the tubes, more or less, unless they are shielded somehow.
All the Best,
Jeff

is there a preferred or optimal diffuser material for a Lumen tube build?

thanks

Largely depends on what you can find, I found a massive 4x8 diffusion sheet at a local place I have been using for my builds just cutting pieces off it little by little. In fact I need to check how much I have left come to think of it.

I found an opaqe diffusion to work best, all the clear ones I tried just didn’t seem to work as well. I did find one that worked but it took twice as many layers and even then it just didn’t feel as consistent with different beam profiles.

Mostly you want something that won’t melt but also lets enough light through that you can get a reading through 2-4 layers but not so much you have to drastically reduce the readings.

thanks Texas_Ace :+1:
i think i have some old fixtures laying around.

i know these are meant for flashlights, but how would they work for light bulbs?
i’m planning on doing some hacking to lower the heat of some cheap bulbs.

thanks again

Depends on the bulb I guess, no idea if the calibration would be correct or not but if only the LED’s were exposed to the inside of the tube and there was nothing dark to absorb light, it might work ok.

right on. i don’t plan on calibrating anything as i’ll just be measuring lights relative to themselves and plotting run time for flashlights.
gonna give this build a go.

cheers

Yeah it works great. I tested my K1 with a 3.5” version. No need to make your own disk. Mine fit great with the second-to-largest insert IIRC.