Yes, an SD2, I have two of them spare because they did not fit the boost driver I was planning to mod them with 
Now it is a convenient 21700 battery compartment with added switch.
And yes, this is still my favorite setup for a big thrower since the first plans for the BLF-GT. Who knows it will be picked up some day by a manufacturer.
Forgot, the tools of today:
Not shown: drill press
Nice start djozz. Looking forward to the rest of the build. 
Thanks Steve!
Today small progress: a mount for the lens made from plywood. Tools: pencil, ruler, drawing compasses, drill, fretsaw, wood glue.
The effective diameter of the lens will be 196mm.
Awesome! I bet it will be a crazy thrower.
Do your students know you are building this? So the above is two pieces of wood glued together to get the step?
No, they do not know that I build searchlights. But they do know that I build stuff myself every now and then, before summer I built a wind tunnel from wood and polycarbonate panels for physics demonstrations (to make wind I used a 10 inch 12V 80W car radiator fan from aliexpress).
Yes, two pieces glued together, I think that I will glue the lens in the slot from the outside after everything else is finished, and keep the lens clean. In fact I have two identical fresnel lenses (they are cheap), one for during the build to check the workings, and one for the finished lamp.
Nice project and thanks for showing ……
Also nice to see “creativity hard at work ……”.
Cheers,
Martin
I’m here for the fun 
Welcome MB, here is some fun 
.
To check the potential of the lens, I clamped it in with a FT03-mini (harddriven SST-40 with dome) behind it. I measured the throw at 6.99 meter from the fresnel lens and got 2.16 Mcd (at 30 seconds). So the potential is there, the domeless SBT90.2 should even do a bit better, and if it doesn’t I can always go SST-40 and have the runtime and less heat.
That is fun indeed!
I admire your creativity and work! An SBT will blow it, not in the “explosive” way! You’ll soon rename your city to Amster…daaaamn :o when that beam hits the sky 
Thanks Martin, and others. The creativity was already 4 years ago, it is more of a rebuild with improvements based on what I learned back then. I like that you do not need to be a fancy flashlight manufacturer to make a superthrower, this thing will look extremely homebuilt . But I must admit that the cost of the parts add up, I’m over 100 dollar already, the led+board+heatsink+alu plate+SD2 were 92 dollar, I can’t remember the cost of the lens, but it was about 10 dollar. Maybe 8 dollar worth of plywood, and a dollar for a handle, so maybe 120 dollar. That is what I paid for the Lumintop/BLF GT a year ago so homebuilding is fun but does not really pay off :person_facepalming:
Well see it like this .... you're now or soon will be ..... the owner of (another) homebuild world exclusive ! ....
... and in "my eyes" that's basically priceless !
Also the "material cost" is probably only a fraction of what the "manual creativity" would have cost ....
... that is if "someone would have payed you to do it" ?
Cheers,
Martin
PS> Let me know when you plan to use it so I can close the curtains first ...... 
A really nice build djozz.
Hope the judges let it in.
If no….you have good chances to win the mod category.
Cool
Modified light category?
A slightly modified SD2
Its not what you spend that matters but what SWMBO knows. 
I’m afraid that despite me not telling all there is, she still knows everything, no idea how she does that, there is no hiding from her :person_facepalming:
I did most of the wood cutting, using ruler, pencil, a jigsaw, a fretsaw, sand paper. It took much more time figuring the dimensions and how to do the focus adjusting than the actual work, and after some changes of design I had to re-make some of the panels.
It resulted in two new features:
*a small silent fan on low power (it is a 5V fan that runs on the single li-ion cell) blowing between lens and led will keep the lens and interior a bit cooler.
*it is going to be a zoomie! :sunglasses:
That’s going to be one cool zoomie.
I hope so
WIP
