Light Leakage at MHS Optic Chamber

[Mad Hatter]

I'm in the midst of building my first saber, and have a question for you experienced folks... :)

I was originally planning on putting an LED in the hilt for a crystal chamber, but it doesn't seem like my setup (~50mA max) will allow for a real bright LED. (Using the progressive on for CF, so the light will fade in/out with the blade.)

So now I'm thinking about using some fiber optic cable to "steal" light from the optic chamber in the MHS emitter section and route it back to the crystal. I don't have my LED yet (going to use the new 10W), so I'm not sure how much light is wasted inside the emitter vs. what goes out the optic into the blade.

Can anyone tell me if I should expect a decent amount of light if I put the fiber optic cable through the heat sink into the optic chamber? Or is this likely to be even dimmer than a dedicated 5000mcd LED?

[Eandori]

Personally, I would just wire up another luxeon for the crystal chamber then drive it at 50mA. They are very bright even at low currents like that. Plus, at current that low it won't get nearly as hot so heatsink is much less of an issue then a fully driven luxeon.

To power it, I would either tie it in parallel to your main luxeon with a biasing resistor, or use a single pull double throw ignition switch that turns on that luxeon straight from the battery (again with a biasing resistor). Since you are only taking 50mA, stealing main luxeon current would probably work best.

Say you were going to use a green K2 on the crystal chamber... It's around 2.4v forward at 50mA. That equals 0.12 watts of power being disspated. Compared to the typical (4.2v x 1.5A = 6.3) 6.3 watts of power that LED is normally driven at in sabers. That's 52 times more power being used when that LED is a main LED... and thus 52 times less power being used in the setup I'm suggesting. That equates to MUCH less Heat.

Seriously run a luxeon at 50mA. They beat the CRAP out of a normal LED in brightness.

[Mad Hatter]

Thanks Eandori. I was going with a normal LED because I was going to use an RGB. That way, when I switch blade colors, I can just flip a switch to match. The fiber optic would take care of the color change automatically.

I hadn't thought about using a lux. I suppose that would be much brighter. Unfortunately, I can't direct an RGB rebel straight into the crystal, and I'm not sure I've got the room... Something to think about though. Maybe I can come up with something...

Before I give up on the fiber solution, can anyone tell me how much light leaks around the optic?

[Dark Helmet]

well, light isn't like water, if you have a way to "tap" a bit out with fiber optics I would say you have very little to worry about as long as you don't cast a shadow in the blade...but, fiber optics are very hard to work with too, you likely spend more money on that than doing it Eandori's way. But here's the other thought, how important is that crystal chamber? if you plan on using rgb then you will need controls for it too, thats 3 pots that will take up a bit of space in the hilt...it would be really cool if you pull it off with the controls and the crystal, providing you can see the crystal while the hilt is together (true bling!) but most rgb sabers are compromising a bit of space to start with.

[Mad Hatter]

I was hoping to catch some light from the sides of the optic. That's why I'm asking about leakage... I'm curious how much light escapes out the side of the optic assembly into the MHS optic chamber.

As for the RGB, I have an extremely small (1mm x 3mm x 8mm or so) SP3T switch. I don't need to use pots because I'm not mixing colors. I just want R or G or B, depending on the blade color (swappable single color 10W). I've got room for the crystal chamber, and for the switch. (And, yes, you can see the crystal from outside the hilt.) And I've already got several sizes of fiber optic cable I can use.

I'll probably go with an RGB rebel star before the plain LED. I like that idea. Especially if 50mA of rebel beats 50mA of plain LED.

But I'm still curious about light leakage at the optic... ;)

[Eandori]

Yeah dude, seriously. Put a luxeon at 50mA next to any other standard LED at 50mA. It's rediculously brighter for the same power usage.

If you are going for the "crystal chamber" look, I had an idea. An optic lense, mounted on the clear lens holder is actually very "crystalline" looking. If you had a few windows into your saber core and you could see that, it would pull off the "crystal" effect really well. Beyond that, the extra holes would work like vents to help cool the LED.

Heck, you could even slap a few pieces of crystal or crystal looking plastic over the outside of the lens mount and get even more of a Crystal look. I think that would work really well.

[DARTH KALEL]

yeah I really like that idea alot, hey it's a nice touch to make your sig go strait to that vid compare you did, slick man.

[Eandori]

Thanks, I was actually just thinking about what a slick looking yellow blade your saber in the picture has.

[DARTH KALEL]

thank you sir. I am in love with the P4 i'm going to be trying the P7 here soon. 740 lumnes should be pretty crazy no matter what color, but crystal chambers and design is what's got me locked right now.

[Lord Maul]

You can run a 1W luxeon off the secondary LED port on a CF with the addition of a power Xtender, you know ;)

Erv recommended that method for me on my saber...Now I just have to get a CF :p

[Mad Hatter]

Yes, but the power extender is just on/off. Running the crystal LED and motor in parallel with the main output will pick up the pulse/flicker/fade effects to match the blade.

[Lord Maul]

I forget how Erv said you could do it, but I know that it is possible to keep the extend/retract/flicker effects in the crystal chamber LED. I'd try PMing Erv.

[Mad Hatter]

It was in my last post ;)
You run the motor and crystal LED in parallel with the main output.

In other news, I just ordered an RGB rebel. (Man, those shipping costs are murder...) Thanks for the idea Eandori :)

Now I just have to figure out how to mount it with my current setup..

Anyone know of a clear material that can be sculpted/shaped, and that won't mind a little heat? The end caps for my crystal chamber are made of acryllic, but I'm going to need something transluscent in the center to mount the crystal now. (The plain LED setup used a rubber grommet in the center. The LED went in one side and the point of the crystal in the other. But the RGB isn't centered in the star, so I need a new mounting idea that won't block the light.)

[Stevegel]

It's not that hard to work with fiber optics. I plan on doing this myself. why bother with another power LED or something. it's the tubing with how many counts of fiber it's in, that will give the light you want. I have miles of Fiber sitting at work and waiting for my stuff to come in and try it out.:D

[Novastar]

It was in my last post ;)
You run the motor and crystal LED in parallel with the main output.A warning on that though... be careful NOT to tie into BOTH the + and the - when running something "with" the main Luxeon. If you tie into both + and -, you will be stealing current from the Luxeon, and so it will NOT be running at the current specified in your config.txt file.

[Mad Hatter]

Nope, just taking the +. :)

[Mad Hatter]

Well....

It turns out that the RGB Rebel ISN'T brighter at low power levels.
I compared a high-brightness RGB plain LED to the rebel - both running at about 50mA - and the two are pretty comparable.

If anything, the plain LED is a bit brighter... :confused:

I'll have to play around a bit more, and see what happens when I bump up to 100mA. I expect the rebel will pull ahead. But, given my low current environment, I may be sticking with the plain RGB after all.

[Novastar]

Mad--you might find this to be true of most any LEDs... if you power them with an extremely low current/voltage... there is simply no way to start VISUALLY discerning "1 lumen vs 2 lumens", heheh. :)

Think about it... after all... we can barely visually discern between 100 lumens of green and 120 lumens of green.

So you might be right that if you're PLANNING to drive an LED at 50ma or 100ma or even 500ma... something like the Lux Rebel RGB is not going to be ideal.

I should have paid closer attention that you were going to use the Reb for a "saber crystal"... and NOT for the main blade LED. D'oh.