pointless mods: a high CRI lighted tail (bonus: Cree XD16 test)

Yes, they came from Clemence, I would not know another source for these rare leds, although leds.de (Lumitronix) has a good assortment of current Nichia leds.

Ah, for some reason my 2000K E21A’s had showed a higher color temperature of 2350K in my tests. Even with a faceted reflector and a frosted lens blending the light, I couldn’t get the CCT lower. It makes me wonder as the E21A looks like overdriven SON/HPS and PC Amber looks like under-driven HPS/SON, I wonder if the Luminus 1800K cube will look like stock HPS but with high CRI.

Just checked: in my Tool AA on a 14500 battery, the E21A is driven at 1.1A, reads 2100K in the hotspot and 1970K in the spill just outside the hotspot, both slightly under the BBL. The Tool has a (quality looking) AR-coating on the lens though that can mess a littlebit with the tint.

I have my setup in a quad with a 2.8 amp driver. Maybe, I’m not pushing the needed amps into the four emitters to get the color temperature down? Is it one of the cool white sst range that color temperature shifts on it’s drive currents, I think? It could be the optics at play like you said as well, and even metering equipment inaccuracy.

I hope it not metering inaccuracy because that is difficult to check, you mostly need to trust the manufacturer for that. The only check that I could do on my spectrometer myself is that I recorded a Helium lamp spectrum and at least all peaks were within the nanometer accurate. But that is not all that can be wrong.

As an addition to the OP, I wanted to reduce the red peak a bit more to see how that affected things, and at the same time get a bit more light overall, so I swapped the 8.9 kOhm resistor of the XD16 string to 4.7 kOhm. Result is 0.0016 lumen, so indeed a bit more :slight_smile: , but what happened to the tint?:

Again a bit higher CCT as expected, now 2210K, CRI similar with R9 a bit down (but still great) and R11 and R12 went up, but still just a bit under the BBL. I’m ok with that for a firefly illumination so I keep it this way.

Nice mod Djozz, now you just started a DIY CRI/CCT making! :+1: :beer:
You should try mixing those colored E17A you have. I guess mixing any warm white LEDs with Amber and Red E17A will create extremely warm CCT with excellent CRI. They have VERY wide spectrum band compared to normal colored LEDs. I tested them and surprised to see the Amber looks much better than LPS.

[Clemence]

I agree. The XP-E2 PC Amber has a CRI of about 42, double that of HPS while retaining a very gold-ish color of under-driven HPS/SON.

If you are curious about the 1800k 90 CRI Luminus Cube:

Exact part number: 1616-1103-18-90

Luminus is saying the Cube can be ran at 300 milliamp. With the DTP from Clemence, you think 700 milliamp drive with x2 7135 regulators would be good?

I never did anything with those colour E17A’s I’m afraid, but I will at some point, they are excellent for colour mixing.

Another day, another idea for a project. I remember that sometime 2013 I decided that I had made my perfect EDC flashlight (with 219A 92 CRI) and that my hobby was finished :person_facepalming:

What 219A was that, was it the warm white one from fasttech?

That was back in 2013, Fasttech did not exist at the time, I got them from Illumination Supply which is now Illumn.com. They were 4500K and it was then the only high CRI led that was used in flashlights.

Does the subject of LED lighting ever get brought up in your classes?

No, we use 5mm leds every now and then as an example light source, that is as far as it goes.

And I made an array of colour leds from 630nm to 400nm for demonstration of the photo-electric effect (the ability of photons to free electrons out of certain alloys). But that has nothing to do with lighting.

But light efficiency, colour temperature, CRI etc. is not a subject at school.

So your students have no idea what you do in your leisure time? :slight_smile:

:laughing: you made it sounds…. (can’t find the right appropriate words)

[Clemence]

The reason I ask is that when in secondary school someone would ask the science teacher a question like how is a nuclear bomb made and for the rest of the lesson we learnt very little except how a bomb was made. :person_facepalming:

Not a clue. 12-18 year olds on average hardly wonder what goes on in other people, let go showing interest in people older than themselves. But there are a few exceptions :slight_smile: Most student like me and if they notice it at all, they appreciate what I’m doing at school (assisting anything to do with practical work and experiments in the science subjects), but what I do in my spare time is well beyond their universe.

I had this moment too, but worse. In my 2nd senior high school, there was a time when a physic class teacher answered a question from my friend. He explained how rainbow made colors out from white sunlight. He did something so very stupid in my opinion as an 16 y.o student. He could explain a nature phenomenon but failed to understand the basic.

Student: “Sir, if rainbow came from white light then is it possible to combine those colors back to white?”
Teacher: “Of course we can with the help of a prism”
Student: “I tried mixing all primary water color pigments but it didn’t work, why is that?”
Teacher: “You have to be extremely accurate, a slight mistake won’t make it white”

Me: :person_facepalming: :person_facepalming: :person_facepalming: :person_facepalming: :person_facepalming:

I got dumped (for being a constant brat) to this “lower grade” high school, and then I realized all the teachers were also (mostly) “lower grades”. My physics teacher in the former high school taught me that pigment color mixing is totally different from light mixing. I believe him because he demonstrated the difference in front of us. I’m sure Djozz also does this too.
I was a little doubtful Thomas with sharp tongue back then, only proofs could silent me.

[Clemence]