PROGRESS UPDATES:
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Ok well… after watching Oldlumens having fun with those ridiculously large projection lenses I just couldn’t help myself.
I’ve wanted to build a proper big projector style thrower for ages but my attempts always faded out in the concept stage. Couldn’t find the right combination of host and or lens and ultimately the lure of a projected square beam profile wasn’t strong enough to keep me interested. A circular die image of an SBT-70 projected through a monster lens…however….Oh My! The lure is certainly back! :bigsmile:
I’ll make a note right here that I’m not going to be going after the absolute max LUX or throw figures imaginable. I basically just want a novelty light that looks interesting and can essentially project a white laser beam spot onto a target far away. The choice of LED alone should reflect those requirements since there’s far better choices around if maximum throw where a consideration.
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That said I’m really excited by the prospect of what this light can do so I think this one is a go!.
Here is a concept for the light that I’ll try to actually build. (I’ve ordered quite a few of the parts already!)
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Maybe a “tad” front heavy do you think? Haha
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So that’s the goal, here is the component list.
Host: Courui D01 “Big Head” in Black from Gearbest
I love this host and I think it will be perfect as a base for this. The extended elements out the front are all various cheap(ish) metal lens hoods and filter adapters found online and cobbled together as best as possible. I think most of the parts will interconnect quite well but there’s always some amount of guesswork when it comes to replicating these things is 3d. Often based solely on vague measurements posted online and product photographs.
I’ll post up more details of the individual parts once I have them here and can see which ones work and where I’ve screwed something up. Unfortunately it’s not going to be a plug and play type of thing, especially when it comes to mating it up with the Courui body but I’m fairly certain I can make this work.
Emitter: Luminus SBT-70 - 5700K
Need I say more, this thing is just gorgeous. Perfectly round die shape should project a supreme “spotlight” beam. I’m most excited to see one of these things up close and running. Just hope I don’t destroy it! Pricey!
Again we’re not going for max throw here, there’s better choices available when it comes to pure output or surface luminance but this LED is quite a unique thing.
I may end up looking at a DIY Wavien collar type setup inside to salvage some of that considerable wasted light but I’m not sure at the moment.
Lens: Edmund/Archor AX42448 Grade 2 - 113mm Diameter 212mm EFL Condenser
This part is still up in the air a bit, however this is a good starting point. This particular lens is one that OL sampled and ultimately rejected for his projector project. It’s from Edmund Optics and the combination of OD and focal length seems like it would be a good option for me.
I may find something that works even better and provided the outside diameter doesn’t exceed 113mm with a focal length range anywhere between 155mm and around 220mm it will work just fine in this host.
I’d love to find something with a nice AR coating but that seems unlikely or prohibitively expensive.
Driver: ~10A linear Undecided
At the moment I think I’ll be sticking to a linear driver for this light. Whether a stacked 7135 type thing or a driver based on Wight’s 7136/mosfet combo I’m not sure yet. In any case the vF of this LED seems incredibly low so a linear driver actually seems like a good choice to maintain a regulated 10A for most of the battery discharge curve.
Datasheet vF states 3.5v is required to reach 10Amp drive current. That’s at a junction temp (Tj) of 25deg C though.
At a more realistic Tj of 100degrees the vF drops by another 0.2v which brings the total vF down to a really rather low 3.3v @ 10A!
I won’t be pushing this LED too much beyond it’s maximum recommended current of 10A. Someone may come along and say they’re fine and dandy up to 15 or 20Amps or whatever but my taste for over-driving LEDs ends where the price tag per unit goes above $50! Haha, I want it to survive a long time.
Heatsink: Hefty copper pill machined to fit stock Courui
This is hopefully going to be (if enough people are interested) a pure copper pill designed to fit the Courui D01. Offered for a very good price here by forum member NikolaS
You can add him to the list of people to blame for getting this project off the ground
Batteries: Internal 1s3P 18650 standard…maybe…
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Maybe I’ll stick a handle on it and power it off another external power pack :bigsmile: :party:
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Sorry couldn’t help myself, I’ve gone mad enough at this stage that any torch without a tactical handle on it seems rather naked!
Cheers
Linus