RGB Aviator mod

[Chrontius]

Considering an RGB aviator mod for better color rendition, seeing that Atomic Chicken fell off the face of the world. Also considering Nichia GS.

Anyone have any input either way? Is the RGB one possible, or is the Vf too different? Do I just have to carefully tune my resistors? I'd prefer not to screw with them, but...

 

[ampdude]

I'm sure it's possible with the right resistor values. I don't know if the A2 ring is wired parallel or serial though. I wouldn't mind one with some DS or GS led's or some deep red ones.

 

[Grox]

koala is going to be producing an A2 LED ring soon - perhaps you could ask him or he will chime in with some comments.

 

[Illum]

what would be your application? :hahaha:
if you really need RGB capabilities, mod a prism in the place of a reflector and that will give you ROYGBV:laughing:

Thanks for the update, I didn't know that koala started this. good timing!

 

[Chrontius]

Application is EDC. I'm just wondering if RGB color space is going to be better than the blue-and-yellow of most white LEDs, plus I know that monochromatic LEDs are stupidly efficient compared to white, or at least were when last I checked.

 

[2xTrinity]

Application is EDC. I'm just wondering if RGB color space is going to be better than the blue-and-yellow of most white LEDs, plus I know that monochromatic LEDs are stupidly efficient compared to white, or at least were when last I checked.

White LEDs are more efficient than ANY monochromatic LEDs (if what you are interestd in is lumens/watt) by far. As far as I know the very best greens are around 70 lumens/watt. The best whites are 115 lumens/watt. The best RGB warm-white arrays are around 50 lumens/watt. The best warm white LEDs are about 85. The difference between RGB and cool white will be even greater, as RGB efficiency would actually get lower for higher color temps.

IMO someone needs to seriously make a small 3mm or 5mm white LED using a neutral white phoshpor, ie 4000k, NOT the ~9000k that most 5mm LEDs seem to be using these days. If it's possible in a high power emitter, it should be possible in a small emitter.

 

[Chrontius]

Well, so much for that bright (?) idea. Is the color rendition worth the tradeoff in brightness? I'm sure someone here's tried RGB arrays at some point.

 

[2xTrinity]

The "weak link" in the RGB arrays is the green LEDs. They are actually less efficietn at producing green light than a phosphor deposited on a blue LED. Consider that the best blue LEDs have radiant efficiencies of about 50% -- if green LEDs were similarly efficient, they would be producing about 300 lumens/watt! The fact that most are languishing at far lower than that means power efficiency on greens is the worst of all the colors.

That and there's the color mixing issues, which is difficult to do. IMO the best approach would be to find a white LED with a greenish tint to it -- ie too muhc phosphor layer relative to the primary blue emission -- then complement it with red light. Arrays of about 4 Cree WH LEDs, with a fifth red LED to balance the color has produced the best color rendition I've ever seen.

The effect here is similar to what you get mixing incan light with LED light, which from what I understand is what the A2 does inherently.

 

[Chrontius]

Yes, but the incan kinda overwhelms the LEDs on the Aviator. Are you suggesting that two Nicha GS white and one red would make better, more usable light than three white?

 

[Gunnerboy]

Yes, but the incan kinda overwhelms the LEDs on the Aviator. Are you suggesting that two Nicha GS white and one red would make better, more usable light than three white?

Incans are deficient in blue. My A2's SMJ's have a slight, smooth blue tint which to me, combine with the incan to improve color rendering.

Gary

 

[2xTrinity]

Yes, but the incan kinda overwhelms the LEDs on the Aviator. Are you suggesting that two Nicha GS white and one red would make better, more usable light than three white?

Yes if the red is significantly underdriven. IMO 4:1 is a better ratio if all are to be driven at the same current. The idea is just to counteract the weak red output on the LED for color rendition, not make the light itself look pink.

 

[mwaldron]

Each LED in the A2 has it's own resistor, they're in parallel off of the 6V battery supply (unregulated).

I've done a few A2 led ring mods now, I'm not sure you'll get better CRI buy using the LEDs in an RGB arrangement, but it's certainly interesting idea worth the attempt.

FWIW, a GS led mod is certainly worth it. I updated my white A2 with GS leds and swapped the resistors for sane values (SF was significantly overdriving the old LEDs). Because of the significant drop in current it's only marginally brighter than the stock white A2, however all hits of angry blue leds are gone and it makes a very nice smooth white wall of light.

Also, in my attempts for better LED CRI I found a supplier of ~3000K white LEDs that was willing to send me two for testing. They were spectacular (very incandescent color) but unfortunately their minimum order was above my ability to justify for a hobby mod. These were the best rendition I've seen. I keep checking with them in hopes they can sell me just a few.

 

[2xTrinity]

Also, in my attempts for better LED CRI I found a supplier of ~3000K white LEDs that was willing to send me two for testing. They were spectacular (very incandescent color) but unfortunately their minimum order was above my ability to justify for a hobby mod. These were the best rendition I've seen. I keep checking with them in hopes they can sell me just a few.

Perhaps you should consider arrnging a group buy -- I'm sure you'd get enough interest as there has been a real lack of warm and neutral tinted 5mm LEDs.

Probably the best tradeoff between efficiency and CRI would be a mix of cool whites, warm whites, and deep red (preferably a bin around 640-650nm). You would end up with a broad spectrum 4000k mix.

 

[mwaldron]

Yeah, that might be a good idea. I need to look into what the rules/requirements are for that and see if the company will quote me a price.

 

[schiesz]

I updated my white A2 with GS leds and swapped the resistors for sane values (SF was significantly overdriving the old LEDs). Because of the significant drop in current it's only marginally brighter than the stock white A2, however all hits of angry blue leds are gone and it makes a very nice smooth white wall of light.

Can you share what "sane" value resistors you used? I am about to attempt this exact mod and wondered if a resistor change was in order.

 

[mwaldron]

I just ran the numbers directly from the GS data sheet using a 6V supply voltage.

I don't remember what the value was, but I can look at my notes when I get home. I'll try to get that for you tonight. I seem to remember SF used a resistor 2-3x lower than it should be.

You'll need surface mount resistors, 0805 IIRC to do the job.

-Mike

 

[ampdude]

I just ran the numbers directly from the GS data sheet using a 6V supply voltage.

I thought that the LED's are supplied by the same 4.0 or 4.2V regulator that the incan bulb uses. They are separate?

I'm very interested in doing the GS mod in mine. Now I need to find a place that sells the LEDs and resistors. :huh:

 

[mwaldron]

I posted a big long reply to this last night before I went to bed, but now it's gone! Maybe I just dreamed of posting the reply.

To sum it up though:

The LEDs are not on the regulator. They are unregulated and fed directly from the 2x123 (6V) supply.

I used 75ohm resistors in my modification, which put me ~30mA for my LED current.

I'd recommend 100ohm if you're partial to RCR batteries in your A2.

You can buy resistors from Newark.

I don't know where you can get GS leds. I got my lifetime supply from a groupbuy at CPFM.

I had currents and prose and all sorts of things short of flowcharts and graphs in my post last night. Perhaps it was just a dream...

 

[batman]

So how does one mod their A2 with Nichia GS led's?

 

[Gunnerboy]

So how does one mod their A2 with Nichia GS led's?

Simply remove the three screws holding the LED ring. Desolder the three stock Nichia CS' and solder in place the GS'.

I will be using the Nichia GS' from the fauxtons I ordered from DX in one of my A2's.

Gary