(prototype) the GT Mini

Interested

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He started sending out purchase details today, and we’ve been ordering lights. Go sign up! :slight_smile:

Does anyone have details about the driver, like the circuit design and ideally also source code? If it’s using NarsilM, there should be code for the GT-Mini version available since it’s a derivative work of a GPL-licensed project.

Code would be the most helpful thing for getting Anduril to run on it. An actual working unit with an unglued driver would help too, but probably isn’t necessary if there is reference code.

About the earlier discussion of lumens…

There are several different units in common use, and all of them are called a “lumen”:

  • The main one is the ANSI standard lumen. Maukka has calibrated equipment which uses this scale. I think djozz may be using it too.
  • The most common on BLF is the Zebralight/cpfselfbuilt lumen scale. It usually runs about 40% higher than ANSI lumens, so a 100-ANSI-lumen light will typically read about 140 lumens on a zebraselfbuilt scale. I think this is what I’ve been using, since I calibrated my light box to match selfbuilt’s numbers and Zebralight’s numbers. I think it’s also what DB Custom uses, and several of the other modders here on BLF.
  • Texas_Ace light tube lumens. I hear these may be higher still, but I don’t know the details.
  • Every other person’s home-calibrated light box. These all differ from each other, so the numbers are only really comparable to other measurements by that same person.

Additionally, there are other factors making this more complicated:

  • Emitter lumens vs OTF (out the front) lumens. A bare emitter measures higher than one housed inside a flashlight with various optics. I think this may have been the origin of the Zebraselfbuilt scale, in part. The OTF Zebra lumens are often pretty close to the ANSI OTF lumens, at least in some lights.
  • Measurement timing. Numbers measured at start are usually higher than measured at the ANSI-standard timing of 30 seconds.
  • Sag. Output sags over time in a lot of lights. ANSI runtimes technically go until the light sags to 10%, IIRC, but this value is misleading. 3 hours at 1000 lumens may actually be 3 minutes at 1000 lumens and then 2h at 200 lumens, then 57 minutes at 101 lumens.
  • “Chinese lumens / Ultrafire lumens”. Marketing people like to make up numbers to try to make lights sell better, especially on cheap items. Often times they’ll take the emitter’s maximum rated ANSI emitter lumen output and claim the product does two or three times as much. This number has very little relation to actual real-world performance.

From what I can tell, the GT-Mini will probably make about 1200 OTF Zebra lumens, slightly less than the Emisar D1S’s 1300-1350 OTF Zebra lumens. The number is probably lower on an ANSI OTF scale though. And it’s almost certainly not 2000, unless we count Ultrafire lumens… in which case it’d probably be about 2500 to 4000.

Since I have plans to mod my GT mini, I’ll pull the driver and send it to you when I get the light TK…. :wink:

It may be totally unnecessary. The manual indicates it’s running NarsilM 1.2, I think. It might be totally unmodified from what’s on the big GT.

If that’s the case, everything might “just work”. So, definitely try it first… Also, I may be travelling for a while and may not be able to receive packages or get much done. So I hope things will work as-is without any changes.

Which one do you like more?

Edited:Link……

Logo poll

Order placed. Can’t wait to get mine!!

I’m not too familiar with the Zebralight/cpfselfbuilt lumen scale.

DB Custom, Robo819, Richard at MTN and Tom E use the Manxbuggy1’s lumen tubes which I think are only 10% to 15% higher than Maukka’s readings. (certain throwy lights might be a bit higher due to no diffusers in the design)

Texas_Ace’s personal lumen tube did read a bit higher than the ones above. About 30% higher than Maukka’s. After getting some reference lights shipped to Maukka to test, he has adjusted his tube down to match. All of the Texas_Ace Lumen Tubes he sold have also been adjusted down to match. Officially he still states about a plus or minus 7% range on them.

Maukka has also decided to sell a small batch of carefully measured and documented lights for anyone who wishes to calibrate their own integrating sphere/lumen tube.

I think the bottom line is if you want exact lumen numbers your gonna have to buy a $10,000 professional integrating sphere.

If you don’t want to spend that much money, you can ship a certain light to be tested by someone who does have one. This is slow and can get very expensive the more lights that need to be sent.

The next cheapest method is to just build your own device then calibrate it with a certified light from someone like Maukka.

The cheapest and probably best way is to just buy a Texas_Ace Lumen tube. It’s already calibrated plus is very well thought out. Plus you get lumen readings right off the lux meter with no math involved.

The two homemade options are always going to have bigger tolerances, but they are much more practical and cheaper.

As an addition to ToyKeppers post above:

The djozz-lumen is the output of my Sunwayman D40A on high setting divided by 550. It was established a few years ago and I keep it as my standard because it is consistent over all my measurements, and with the D40A always available it is easy to maintain.

Since then I have learned that the djozz-lumen is likely higher than the real lumen, some comparisons that I did in Germany with flashlights measured before in the LedLenser sphere, and an exchange of 2 different flashlights with maukka suggest that the djozz-lumen is on average around 9% high. But compared to maukka’s setup a high CRI 4000K flashlight (the 348 light that maukka is selling now for calibration) produced a bigger difference (11) than a 5000K 70CRI Nitecore P12 (7), so despite using a very high quality well V-lambda corrected luxmeter I have a spectrum sensitivity difference with maukka as well.

And lots of people think it’s easy to measure lumens. Just buy a lumen meter on ebay, they say. :person_facepalming: It’s funny.

I think the general consensus is that warmer tints do read a bit lower in lux compared to cooler tints, but this is still debated. I try not to think too much about it. It makes my head hurt. Lol

I’ve considered buying a calibration source from maukka. Before doing that though, I’d need to build a more proper integrating sphere… and I’m not sure I care enough to do that.

So I have a very cheap and compact measurement device with calibration based on a couple Zebralight SC52s, selfbuilt’s reviews, and a few people who were publishing numbers on BLF a few years ago. And it almost certainly reads between 10% and 50% higher than an ANSI lumen.

The downside is that it’s known to be skewed. The upside is that it typically matches most manufacturers’ published specs pretty closely. But then, another downside is that, apparently, most manufacturers exaggerate. :frowning:

Also, since what I’m using is small, it can’t handle more than about 2500 lm without some sort of attenuator. So I get to mess with neutral density filters while measuring bright lights.

But back on topic, it’ll be interesting to see how the GT-Mini performs. It seems like it’ll be a D1S with a nicer host, flatter but slightly lower output, and a more full-featured UI.

Have you considered getting a TA Lumen Tube? When you add up the time and parts cost to build a device that properly diffuses both floody and throwy lights plus an additional $75 for the calibration lights, you actually come out ahead just buying his for about $150 shipped. It’s well thought out and very easy to use. You don’t even need a calculator. :wink:

You can have my HP48GX when you pry it from my cold, dead hands.

Well, okay, actually it pretty much just sits in a box and I use Python to do calculations. But still.

Sooooooooooooo much better

yes that looks alot better, but what about the frontal below the button what will be there?

Probably nothing.

The new font is better than the old one, but I still wish the logo was smaller.

well i dont see why not it cant have the logo atleast ? but a step in the right direction tho.

Do we have an estimate on when the first units are supposed to start shipping? I kinda want to see beamshots of both tints before placing my order. I would have preferred a 5000k option, so I’m not sure which one will be closer to my preferences.