Friends offgrid need amber lights, and NiMH (not li-ion) -- ideas?

[cajampa]

@hank

I’ve tried both old and new f.lux with the MacBook monitor, basically to check and see what the spectrometer detects — but the screen hasn’t been bright enough for the little $40 kit spectrometer to say much, the result comes out like this:
SpectralWorkbench
You can see the bump at the 450nm end; intensity isn’t useful at those light levels though.

The spectrometer software was pretty flaky for a while and is being rewritten now, and I’ve taken the spectrometer apart to build their v3 kit. More news when I have any

Thanks
Interesting, did you use the 1200K setting for this measurment in f-lux?

I found a review of your screen @ Anandtech and it has an ANSI contrast of 796, a black level of 0.42 & a stock white level of 6704K.

This explains a lot or should i say most of the differences, with how we perceive the effectiveness of just using altered gamma ramps (like we do when we use a program like f.lux or Redshift).

My monitor (HDTV) Samsung 46C750 has a ANSI contrast of 3000-4000 depending on how high i set the backlight setting, and a black level of 0.03 cd/m2 & a white level of 6500K.

This means my monitor is 14 times better at blocking the backlight with a gamma ramp, to very warm like 1000-1200K with Redshift or f.lux, or a red & warm bias calibration from the 6500K normal white point if i want.

It is all in the black level or maximum contrast that the display can provide, that limit how effective it is at blocking different frequencies of light.

MG, your monitor has a contrast of ~1000 & if you lower the backlight setting it can get as black as 0.0861, that is pretty good for an IPS monitor, the nice thing about IPS monitors is they have the same contrast, or light blocking ability from all angels you view them from, my VA type HDTV has only the highest level when looked at straight on, as soon as you look at it from the sides it losses contrast, and most likely spills some of that blue light out in to the room.

@MG, you ask “what does the f.lux software actually do to control these leds?” And the thing is that f.lux doesn’t do anything to the leds or the backlight in a LCD display, the colour control in a LCD display comes from the colour filters in the red, green & blue sub pixels And how open or close those sub pixels are.
And the higher ability to close or open & let through light or not let through light, is what gives the perceived or measured contrast or light blocking ability in a LCD display.

And you say that “then the monitor seems to compensate” when f.lux kicks in. I think it is your eyes that compensates, i have used f.lux for years now, and recently added on in house lightning with the same effect.
And my experience is that the more you use it, the more the eyes get use to seeing the warmer colours & it almost look like it use to, at first it looked very very red, & without room lightning in a similar colour i never used the warmest setting, but with all lights the same colour, it doesn’t interfere with perceived contrast for me & i can read just as fast in 1200K as in 6500K.

[chenko]

Did you consider modding Thorfire TG06? Those work with a single AA NiMh and also start on low every time.

[hank]

Thorfire 06
Hadn’t noticed that one but I’ll remember to watch the review thread on it.
Thanks.

[hank]

Fasttech is now assuring me they’re selling an amber SK68 clone,
SKU 2139702
for real, yes, this time. But they’re wrong, still, again.

Greetings.

I have tested this item SKU 2139702 for you,please refer attachments about it
It actually has a “yellow” light.

—— Included below is the most recent message you have sent to us ——
“yellow” and “amber” mean the same thing in English, for LEDs: around 590nm

Can you confirm SKU 2139702 actually has a “yellow” — 590nm — emitter in it as described?
The customer who reviewed it says it’s not as described.

see https://support.fasttech.com/ticket/Q0324DYXMN where a purchaser reports buying one of SKU 2139702 and getting a white, not the 590nm emitter.
——————————————————
Kind regards,
andrea
Customer Advocate

The description is:
Light Source Color Yellow
Light Source Model XP-G
Lumens (Max) 100 LM
Wavelength 590 nm

They still don’t know what they’re selling, near as I can tell.
I’ve swapped a lot of email trying to get this figured out.

[hank]

Aside — here’s an illustration of how wavelengths combine to make color temperature:

That’s a red emitter and a green emitter — and when those are combined the color temperature is yellow.
But this light, while the combination result looks yellow, still has no yellow emitter in it — only a green emitter and a red emitter.

That’s how “warm white” lights can still contain the blue-green wavelengths that mess up sleep, while they look nice and yellowish.

[cajampa]

That is good way to demonstrate how it works & why people we care about need to consider these light spectrum issues.

With more & more led lightning being installed to save on electricity, the pharma industry :evil: can look forward to selling a lot more sleeping medicines :Sp in the near future :weary:

[MG1 (MG)]

Thanks again for the useful commentary. More food for thought and further reading. Like many things, simple answers are insufficient. It gets complicated just below the surface. Cajampa, I am now pretty sure you are right about “eyes that compensate.”

[MG1 (MG)]

Experiment replicated.

Light on the left is a generic red P60 drop-in (*bay $9.64); light on the right is a Killer_Lumens Gen 2 XML with his custom color shifting driver driving the green side. Original picture is much better, the upload resizing did something to the colors.

[cajampa]

@MG

It gets complicated just below the surface. Cajampa, I am now pretty sure you are right about “eyes that compensate.”

One related interesting angle on this phenomenon is.
The pain you feel in your eyes when your eyes is dark adapted & you get strong day light or white light in them, is the rhodopsin pigment that is reduced chemically & heats up your retina, and you feel that as pain.

This rhodopsin gets transparent by light and you lose your night adapted vision, and when you remove light frequencys that have the strongest effect the blue & green, rhodopsin slowly recycles to give you your nightvision, red also reduces it but much more slowly.

One cool biohack I recently learned was one of the reason, why i have unusually good night vision is, i eat a lot of black currant every day & have for years, it is a good source of omega 6 GLA among other things, & it contains anthocyanins that actually make the recycling of the rhodopsin faster in the rods in the eye.
And the result is improved night vision & much faster night adaptation

If someone wants to try, remember that it is dose dependant, as in the more you eat the stronger the effect and lots & lots of carrots is always good

[Mr_Nobody]

slightly offtopic, as i already have a amber thrower, decided to mod my sipik sk68 and drop this emitter in it https://www.fasttech.com/products/1609/10007033/1574702

[hank]

I found an exhaustively thorough (up to 2013) review article here with extensive references — lots still being learned about this whole optical system:

http://www.sciencedirect.com/science/article/pii/S0166223613001975

(search Google Scholar for “melanopsin” if you want to find more like this — that’s the particular kind of “opsin” used by this system that affects melatonin regulation among other things still being discovered)

tidbits: it’s still an open question even how to measure levels of illumination that affect this system, to determine what is produced by an emitter as well as how the body perceives the light. Much discussion of that.

“… peak sensitivity in the short-wavelength portion of the visible spectrum (from 447 to 484 nm) …”

“… it was originally thought that illuminance of 2500 lux was required to suppress nocturnal melatonin in humans, but later studies have shown that under certain conditions, as little as 1 lux or less can suppress melatonin in humans …”

[hank]

> Fasttech Cree XP-E

yeah, those (amber) ones from FT — find them with https://www.fasttech.com/search?590
are what I’ve mostly used for giveaway amber flashlight mods — they’re much cheaper than my preferred
PC Rebel Amber emitters http://www.luxeonstar.com/pc-amber-591nm-sinkpad-ii-10mm-square-led-140lm

The XP-E2 may be closer to the PC Rebel, I haven’t compared them side by side yet.
The reef lighting page has: Cree XP-E2 Color announced with upgrades over original | Reef Builders | The Reef and Saltwater Aquarium Blog

The rest of the colored LEDs all have a leg up compared to the Luxeon Rebels of equivalent color. The difference in performance increases greatly at higher currents [now rated for 1000mA], as the Rebel amber, red-orange, and red are still limited to 700mA. What we have here then is a pretty decent upgrade over the original XP-E, with a few shortcomings.

although the PC Rebels come on Sinkpad 2 boards, and I’ve been able to push them fairly hard.

[chenko]

Wouldn’t a (precisely made) colour filter let only the desired wavelength pass? If so, any high cri or incan source could be used maybe…?

[hank]

> color filter

Look at a spectral curve for a white LED

and compare that to
the spectrum of an amber (or any other single color) emitter.

Yes, a narrow band filter will pass only the range of wavelengths specified.

With a filter over a white light source, you convert all the rest of the photons into heat — and get out only the range that passes the filter.

(The latter two illustrations I just turned up with ’oogle. They are for lights used to control light pollution, linked from this page: Rosemont Copper Light Pollution Mitigation Project - (520) 884-0045 )

[hank]

P.S. — look at those typical spectral curves for “white” LEDs and you’ll see why they (or any “fluorescent” light source that uses a phosphor) can interfere with sleep.
That tall peak lies right over the narrow band of the melanopsin receptor.

All the rest of the spectrum should be no problem.

Now if streetlights had the kind of super effective masking that high end monitors do, they could be adjusted. Not likely, too expensive.

P.P.S.: in today’s news: How Light at Night Affects Preschoolers' Sleep Patterns (Video) - Slashdot

[hank]

RMM (mtnelectronics) is now stocking PC Amber emitters on 16mm and 20mm Noctigons

CREE Amber XP-E2 on 16mm Noctigon MCPCB

[Gurthang]

Good info Hank. I’d say ‘cool’ but in this case…. “warm, very warm”.

[hank]

Here’s an oddity:

Claims:
LED Type:4-Chips XPE led
Power 12W
Working Voltage :2.2-2.5V
LM:1200LM Max
Current: 1.5-3A
Copper PCB

they have other colors as well. Hmmm ….

[Sciencetists]

If were dredging up this old post I figured it would be prudent to post this source for Amber emitters.

Stevesleds.com has the Luxeon Rebel ES in Amber for 2.75/pc mounted to a 20mm AL star. I have purchased from this website and was very happy with the service.