Just off the CNC - Update: It's Alve!

LOL

Oh yeah . . . would look killer on the front of my Passat.

And, as for the SST-90s . . . a big die that needs a lot of juice to perform and I doubt there would be any noticeable increase in brightness. I also agree that there would be little if any advantage using a few XP-Gs, other than less light. Once it's up and running, I predict you won't be saying, "I wish they threw better." There's going to be some reach for sure but I suspect aiming won't be an issue. It will basically be this insane horizontal of lightning from a distance and since it's flat, it might illuminate the shoulders of the road pretty well.

Actually, the more I consider aiming, the less sure I am about what you'll see from behind the wheel. I'm a novice so, this is probably all redundant to you. As is everything on the base being able to withstand over 170 degrees F sustained. Is that about right? A little high, perhaps?

Sorry - just can't seem to stop thinking about this . . . pretty damn awesome.

Foy

I felt the same way about the XP-G's - that's why I decided to kill them off. The might add a little throw, but it will be completely insignificant when placed inside the wall of light that should come out of this thing. SST-90's certainly DO put out a little more light, but they do it with (as you say) a bigger die, yielding much more spill and much less throw. They're also quite a bit less efficient (twice the output with 3x the input)

The beam pattern is not going to be horizontal, it will still be a circular output. The width of the enclosure is only 15 inches, essentially nothing once you get out more than a few feet from the light.

Every single component that I've selected (metals, plastics, electrical parts) is capable of sustained operation at 125C (257F). Even the PCB is built using upgraded material (FR4-TG170 instead of regular FR-4). My cut-off will be 100C, which is where the light will automatically start backing off to prevent damage - but this is a very cautious number. 125C really is no problem at all for the parts. Even 100C should never be seen though - the thermal analysis suggests that absolute max will be around 80C, and that's in a VERY hot 90F ambient environment with almost no airflow.

PPtk

15-inches. I guess I need to read a little closer. I had it bigger in my mind for some reason. For the light you're going to get, that's pretty small. Actually kinda funny when you think of how big some Cibies are.

Anyway, looking forward to seeing it . . .

thanksforsharingFoy

All understood still very keen, can't wait to see your finished product.

:) First signs of life. I had a little spare time tonight, so I started putting components on the circuit board and doing some basic testing. So far, all good news. The op-amp based current sense circuit works perfectly - I'm only using a 0.01 OHM Current Sense resistor (to mitigate power loss in the sense circuit), and the 50 to 1 op-amp works beautifully. At 3 amps, I'm seeing 1.5143V out of the sense circuit - well within the 1% component tolerances - and it's stable and quiet.

The DSP is soldered down - always fun soldering a fine pitch QFN by hand with an iron. 3 XM-L's are in place, and the first lumens have been emitted. I ran it up to 3 Amps for just long enough to measure the current sense output, but with the paper-thin circuit board not being attached to a heat-sink of any kind, it gets HOT in a hurry. 1.5 amps is about the most I can run for more than 5 seconds without risking damage.

All in all though - a successful beginning.

Pictures of the process:

This is the 64 pin QFN part drowning in water soluble flux. The tip of the soldering iron is in the picture for size comparison. 3 XM-L U2 Parts are also visible. Those are a real pain to solder by hand - the only real way to do it is with two irons. They look good though - nice and centered. At the far right of the picture, you can also catch a glimpse of the 50:1 Op-Amp. I love these TI parts - very stable, and very tiny.

Side view of the pads of the QFN. Soldered up nicely, considering it was done by hand rather than reflow. You can also see a few 0603 caps and one 0805 cap.

A picture of the emitters through the TIR optic. These Cute-3-XML optics from LEDIL are very well made, I have to say.
You can see how perfectly centered the emitters are in the optic though.

The emitters lighting up for the first time. This is insanely low current - 0.001 Amps (1 milliamp).

Emitters fired at 50mA with TIR Optic in place.

Emitters at 1.5 Amp With TIR Optic :)

Overall, I'm very satisfied with the results thus far. The THIN (0.3mm) circuit board was a good move - it allows heat to move from the emitters to the back side of the board (and into the enclosure) through the vias with incredible efficiency. There is no doubt that a THIN board like this with heavy copper and LOTS of via's will perform better than an aluminum star board. At 1.5 Amps, Its less than a second before the back side of the board is WARM - which is good - it means the heat is moving away from the emitters rather than staying trapped in them.

More tomorrow, I hope.

PPtk

Looking brilliant :)

Some of us might be interested (at least I am) to just buy the circuit board and stuff without the parts installed. You should take this also in consideration. The buyer will install the parts at his own risk. Less work for you, more satisfaction for the others.

Very nice project indeed.

Maybe a smaller light (bike light) for the future ? :)

Great build along, thanks for taking the time to share it with us.

This looks excellent.

If I can offer an idea for the future ... perhaps make the circuit board modular? 1 module for 3 XM-Ls? That way anyone can order 3, break 1 at their first try at soldering, and later use 2 for total of 6 XM-Ls. Or similar.

You get the picture.

Viktor

That's one thing I've enjoyed learning since I began this "flashlight thing" the need for a thermal pathway and the different ways to route heat away from the emitter/board or whatever. Nothing to absorb/move heat = very bad.

Again, I apologize if you've already answered this but am I right assuming the part of the TIR next to the emitter does not actually touch the emitter? Is it dished out a little or flat and mounted held away or . . . . does it touch?

I find myself wishing the TIRs were larger in diameter and maybe a little deeper . . . . so, I guess I have to ask; how big are the TIRs? Not a huge deal - just curious.

Foy

The need for a thermal pathway is so often either misunderstood, overlooked, or written off as too difficult. Without an excellent thermal pathway, you could have a heat-sink the size of an aircraft carrier and it will not matter - if you can't get the heat from your source to your sink, then your sink is irrelevant anyway.

The TIR's that I'm using are 35mm in diameter (for 3 emitters) and about 15mm high. bigger ones are available though! The Iris comes to mind ( http://www.ledil.com/node/2/p/2651 ) at 38mm in diameter and 28mm tall for a single XM-L.

The Khatod PL353CTL is also a big optic at 50mm in Diameter and 22mm in height for 3 XM-L's ( http://www.khatod.com/cms/pl353ctl_series___triple_lenses_for_cree_xlamp_xm_l_leds-2705099-2705099.html# )

TIR Optics are also different animals than reflectors. While bigger is still 'better' for the beam, it's less pronounced with optics than it is with reflectors. If the design is good, an optic shouldn't 'need' to be huge to produce a very nice beam profile.

The optics that I'm using (CUTE-3-XML) are hollowed out over the emitter - they don't 'touch' - but they're very close. I would be hard pressed to say that there's a full millimeter between the lens of the XM-L and the TIR optic itself. Even this small gap, however, helps to keep the heat from the emitter from dissipating into the lens rather than the circuit board.

PPtk

Have you seen any MPCBs suitable for the 50mm Khatod?

That optic looks like a killer piece for retrofitting triples.

FWIW, the 3-up CUTE optic is what I used on my last triple conversion. Very efficient and thermally stable.

man i'd love to install one of these on my scooter lol..seriously! would have doubts about supplying it with enough power though..

What an amazing thread!! It's really interesting to see the engineering thought process behind the design of the light. I wanted to go into mechanical engineering when I was I was in college, but my math just wasn't good enough. I ended up in IT doing business software instead. (once a nerd, always a nerd).

It will be interesting to see the beam pattern once you get it all together and running at full throttle. Although your design isn't conducive to a curved light to create a wide beam, having a set of emitters at each end of the light set outwards at 20 to 30 degrees might provide more peripheral light. Sort of like a built-in cornering lights. (Please understand that I am NOT arm-chair quarterbacking! Just thinking out loud.)

Can't wait to see the pictures of it in action on your Jeep. Aren't you concerned that the light beam will catch bushes or trees on fire as you drive past?

Thanks so much for taking the time to share this process with all of us!

Joanne

This thread makes me wish I went into electrical and/or mechanical engineering. For now I'm stuck flashing C programs onto assembled microcontroller boards using code developed by someone else, then wiring them into a heatsink developed by someone on the CNC and installing it into a Maglite. Makes my "modding" seem so very modest.

I can see a lot of off-road guys wanting a product like this, depending on the price. You should send one in to Xtreme 4X4 on the Power Block :)

I haven't seen any, but they're easy enough to make. MPCB's are somewhat of a sham anyway - they conduct heat less well than a thin circuit board with heavy copper and lots of via's.

Further, I've not even seen the 50mm Khatod optics for sale anywhere. You might be able to buy them right from Khatod, but I can't be sure about that. Some companies refuse to sell direct - only handling sales through distributors..

PPtk

At full blast, assuming your scooter has a 12V electrical system, you'd need to supply this with about 21 Amps of current. I kind of doubt the average scooter has an alternator that could keep up with that - but I'm not at all sure.

There is, however, no reason you couldn't run something like this at less-than-full-blast to fit its output to the available power. Even at 50% brightness, which would only require about 11 Amps, you're talking about 12,000 Lumens at the emitter, and over 10,000 out the front (after Optics Loss and Protective Lens Loss). A 55 watt halogen head-light need 4.5 Amps, so 11 Amps is not a crazy number, I would assume.

PPtk

Hehe - Yeah, there's been more engineering thought put into this little hobby project than there is in a lot of commercial products on store shelves. I may have gone a little overkill :) I hear you on the nerd thing - I dabble in Database Administration here and there..

I had actually considered having the outside groups of LED's pointed 30 degrees out to do just what you suggest. There are two difficulties with this plan though..

1) The front protective lens is currently very easy to make. It's flat. Having to wrap that lens around a corner means either bending plastic, injecting plastic, or using three pieces

2) Circuit boards don't bend. Well, they do, they just don't work very well afterward. Again, this means either FLEX (Expensive), Rigid FLEX (Even more Expensive), or three circuit boards (Pain in the Ass)

Neither can I! I'm quite excited to get it fired up, tested, and installed. With as much time, energy, and money as I've put into this, I'm more concerned that the light beam will not catch bushes and trees on fire :)

My pleasure. I've always enjoyed sharing the things that I'm involved in. Thanks for all your kind words!

PPtk

We all have wishes about what we should have gone into - trust me :) The C programs you speak of are really not that complex - you should take some time and learn what they do. Programming a microcontroller isn't horribly complicated - especially with the fairly simple nature of what we're doing here. It's kind of fun, in fact. There are BASIC compilers for both Atmel and Microchip uControllers as well - BASIC has a much easier learning curve for a non-programmer because it's "Natural Language"

Basic Code looks like:

IF PINB.B5 = 1 (If the PIN at PORT B5 is HIGH)
BRIGHT = 127 (Set Variable BRIGHT to 127 - if we're using 8 bit variables, then this is about half)
PORTB.B3 = 0 (Set the pin at PORT B3 LOW)
END IF

We'll see - For now this is a hobby project... I haven't put a lot of thought into making this a 'product'.. I'm not ruling it out, I'm just not ruling it in...

PPtk

oh yeah way too much lol..the 11 amps would probably be possible, but would be quite taxing..it runs 2 35-watts and is able to do 55's..there are even some guys with hid setups and they work quite well..10 000 lumens would be amazing..let me know what you're charging for this setup ;)