Well, I did what I thought I’d never do, I stuck a MT-G2 in a zoomie. But in my defense this light is not for me, it’s for a fellow enthusiast for photography in dark places who want’s a wide zoomie that packs a bit of punch.
The zoomie host of my choice is this one: https://www.fasttech.com/p/1206500 but someone pointed me to this one which appeared to be the same but cheaper: http://www.banggood.com/Wholesale-CREE-XM-L-T6-1800-Lm-12W-Zoomable-LED-Flashlight-Torch-p-51265.html
They are however not the same. The FastTech light has a solid pill, the Banggood light does not. There are a few other subtle differences too, but not really worth mentioning. This mod I’m using the Banggood one because I’m out of the FastTech ones.
I build a few of these lights for others every now and then (this is the first with MT-G2 though) and have previously used Qlite drivers and stacked chips. I have managed to stack ’em but man do I hate it. As I had a trial version of the pro Eagle I got to making a four layer 20mm driver to suite my needs:
The main features:
- MCU on the spring side, which means no more ripping pills apart to flash! Yippee! (Some of you kindly donated small Nanjg driver springs to me for this).
- 15 x AMC7135 chips divided over four output pins of the MCU, meaning I can run any number of 1 to all 15 of them for constant current modes.
- Single AMC7135 chip is on PB0 so I can PWM control it for lower modes.
- Vias for all wire connections, with a through wire to the spring for spring bypass.
- Zener ready with voltage divider resistors, zener diode and zener resistor all on the spring side so switching between zener and standard does not require dissassembling the driver from the pill.
As this Banggood light has a hollow pill I used Artic Alumina to stick some copper washers to the LED, then I filed out slots for the wires:
The plastic sleeve for the LED in this light fits over the MT-G2 perfectly! Where can I buy these? Haven’t seem them for sale anywhere.
Even though this light isn’t for me I still can’t stand the beam of the focused MT-G2 and can’t put my name next to it, so I put a ring of 18awg wire around the pill to prevent it from fully focusing (can be seen in the second driver photo). Works perfectly, keeping the LED just out of focus.
Features of the firmware are 30 second timeout for turbo (steps down two modes), 60 second timeout for high (steps down one mode) and voltage monitoring is tweaked so that when running on turbo, the voltage level for step down is the same is the critical voltage level for all other modes. I did this to compensate for the voltage sag on turbo with the 18350 cells I’m using. Running on high or lower modes is as normal, with low voltage step down and critical voltage warnings. The guy that this light is for does not want the light to shut off when critical level is reached because he might be in a situation where the need for some light outways the health of the cells, so I just put in a warning flash every 30 seconds when voltage level is critical.
15 x 380mA chips is enough for this light, it runs hot fast, and I don’t have to stack any chips! Do I need to stack if I should want more in the future? Hell no! I’ve made a purpose built slave board that fit’s right inside the pill with 16 x AMC capacity. The 20mm driver has two vias for slave board output, either on PB0 (PWM capable pin) or PB3 (which adds the chips to the string of 8 already on PB3 on the master driver).
I also replaced the switch with an Omten switch, potted the hole in the washers with thermal pads and greased the pill threads with thermal compound. The light is ready for him. It still has the plastic lens on it though. I’m looking for replacement glass lens for it and will send him one later if I find one that works nicely. Any tips on aspheric lenses that will fit? Diameter is about 28mm.
I’m happy with the result. It’s a good wide photography light that produces a good amount of light. I might make one for myself, glad to do it now that stacking chips is a thing of the past