[OT] Red monochromatic LED flashlights and/or light bulbs

[Jason White-20]

Hi everyone,

I'm interested in identifying the best way to solve a day to day
problem I have. I like to read at night before sleeping, but I find
certain types of lighting interferes with the normal onset of
"sleepiness."

I suspect that using (nearly) "monochromatic" red lighting vis LEDs
would be one way to address this. I was wondering if anyone could
recommend some "ready to use" easy to buy and test lighting devices
that are effectively "monochromatic".

I think it boils down to three possible items:
* LED strips
* LED light bulbs
* LED flashlights

I can find LED strips on ebay. maybe even ready to use ones with power
supply attached. But the other two seem harder to find. Few items are
labeled monochromatic even if they effectively are.

--
Jason White
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[madscientistatlarge]

Actually, green light is supposed to encourage sleep (haven't tried it myself yet).  I assume it's a response to a tall green field being a good place to nap, i.e. close to food, no need to hunt right away.  What's special about red light is it doesn't make pupils dilate, hence usefull for astronomy and other places you don't want to blow your' night vision.  In my experience red light has no effect on drowsiness, and it would hardly be useful to astronomers if it did.  It won't keep you up like sunlight though (I've worked 9 hour graveyard shifts, overlapping with the manager, once you see sunlight it takes hours to get to sleep, even when you do it every day).


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‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On Wednesday, September 2, 2020 3:20 PM, Jason White <[hidden email]> wrote:

> Hi everyone,
>
> I'm interested in identifying the best way to solve a day to day
> problem I have. I like to read at night before sleeping, but I find
> certain types of lighting interferes with the normal onset of
> "sleepiness."
>
> I suspect that using (nearly) "monochromatic" red lighting vis LEDs
> would be one way to address this. I was wondering if anyone could
> recommend some "ready to use" easy to buy and test lighting devices
> that are effectively "monochromatic".
>
> I think it boils down to three possible items:
>
> -   LED strips
> -   LED light bulbs
> -   LED flashlights
>
>     I can find LED strips on ebay. maybe even ready to use ones with power
>     supply attached. But the other two seem harder to find. Few items are
>     labeled monochromatic even if they effectively are.
>
>     --
>     Jason White
>     --
>     http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
>     View/change your membership options at
>     http://mailman.mit.edu/mailman/listinfo/piclist
>

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[madscientistatlarge]

P.S. afaik all leds not designed to be white or R/G/B or bicolor are fairly monochromatic, if I recall about 20nm half power on the curve.  Most of the variation in center wavelength is thermal.


Sent with ProtonMail Secure Email.

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On Wednesday, September 2, 2020 3:20 PM, Jason White <[hidden email]> wrote:

> Hi everyone,
>
> I'm interested in identifying the best way to solve a day to day
> problem I have. I like to read at night before sleeping, but I find
> certain types of lighting interferes with the normal onset of
> "sleepiness."
>
> I suspect that using (nearly) "monochromatic" red lighting vis LEDs
> would be one way to address this. I was wondering if anyone could
> recommend some "ready to use" easy to buy and test lighting devices
> that are effectively "monochromatic".
>
> I think it boils down to three possible items:
>
> -   LED strips
> -   LED light bulbs
> -   LED flashlights
>
>     I can find LED strips on ebay. maybe even ready to use ones with power
>     supply attached. But the other two seem harder to find. Few items are
>     labeled monochromatic even if they effectively are.
>
>     --
>     Jason White
>     --
>     http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
>     View/change your membership options at
>     http://mailman.mit.edu/mailman/listinfo/piclist
>

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[Clint Jay]

Reducing the amount of blue and shorter wavelength light is meant to help,
beware 'monochrome' LEDs that use phosphors to produce 'odd' shades of
light.

On Wed, 2 Sep 2020 at 22:23, Jason White <[hidden email]>
wrote:

> Hi everyone,
>
> I'm interested in identifying the best way to solve a day to day
> problem I have. I like to read at night before sleeping, but I find
> certain types of lighting interferes with the normal onset of
> "sleepiness."
>
> I suspect that using (nearly) "monochromatic" red lighting vis LEDs
> would be one way to address this. I was wondering if anyone could
> recommend some "ready to use" easy to buy and test lighting devices
> that are effectively "monochromatic".
>
> I think it boils down to three possible items:
> * LED strips
> * LED light bulbs
> * LED flashlights
>
> I can find LED strips on ebay. maybe even ready to use ones with power
> supply attached. But the other two seem harder to find. Few items are
> labeled monochromatic even if they effectively are.
>
> --
> Jason White
> --
> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist
>

--
Clint. M0UAW IO83

*No trees were harmed in the sending of this mail. However, a large number
of electrons were greatly inconvenienced.*
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[James Cameron-2]

We have red lighting throughout house for same reason.  I used a few
red Luxeon Rebel LEDs for point lighting at about 10% of rated forward
current, and about 30m of red Christmas light chains for widespread
lighting at about 35% of rated current.  The chains are a pair of thin
wires joined every few inches with a red SMD LED soldered to the wires
and then encapsulated in a hot glue.  I have night switch assemblies
to turn everything off in daylight; a photodiode with a pullup
resistor to drive a MOSFET gate.  I use Nitecore red torch.  I use
bicycle tail lamps when staying away from home.  They have a USB micro
connector for recharge.  I did find a red "party" light that I cannot
recommend; it contains a white LED filament with a red plastic filter
on the globe.  I've tried reading to red light, but it has not been as
effective as reading to a white light then turning it off when I'm
finished.  You may have one of those engineers' diseases; visual
hypersensitivity.  ;-)

On Wed, Sep 02, 2020 at 05:20:56PM -0400, Jason White wrote:

> Hi everyone,
>
> I'm interested in identifying the best way to solve a day to day
> problem I have. I like to read at night before sleeping, but I find
> certain types of lighting interferes with the normal onset of
> "sleepiness."
>
> I suspect that using (nearly) "monochromatic" red lighting vis LEDs
> would be one way to address this. I was wondering if anyone could
> recommend some "ready to use" easy to buy and test lighting devices
> that are effectively "monochromatic".
>
> I think it boils down to three possible items:
> * LED strips
> * LED light bulbs
> * LED flashlights
>
> I can find LED strips on ebay. maybe even ready to use ones with power
> supply attached. But the other two seem harder to find. Few items are
> labeled monochromatic even if they effectively are.
>
> --
> Jason White
> --
> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist

--
James Cameron
http://quozl.netrek.org/
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[Sean Breheny]

I doubt it is really relevant to the topic at hand (the physiological
effects of light) since the cones of the eye are not capable of
distinguishing monochromatic light from somewhat broader spectrum sources
but LEDs are not very monochromatic. I was playing around with a simple
spectrometer a few months ago and I tested a bunch of sources. Among them
were a Cree red LED, a red laser diode, and some narrow optical bandpass
filters (which I illuminated with a halogen bulb). I have attached a small
image which I hope is not too big for the listserv. It shows the laser
diode on the left, the red LED in the middle, and a 10nm-wide green
bandpass filter on the right. The laser was more monochrome than the
resolution of my simple spectrometer and shows the approximate resolution
of the device (which was just a digital camera, two razor blades forming a
thin slit, a diffraction grating, and an opaque plastic box. I
post-processed the images using a python script to produce the graphs.

Sean


[image: led spectrum.jpg]

On Wed, Sep 2, 2020 at 5:41 PM madscientistatlarge <
[hidden email]> wrote:

> P.S. afaik all leds not designed to be white or R/G/B or bicolor are
> fairly monochromatic, if I recall about 20nm half power on the curve.  Most
> of the variation in center wavelength is thermal.
>
>
>

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[Bob Blick-5]

I let it through. Thanks for the contribution, Sean!
Friendly regards, Bob

________________________________________
From: [hidden email] <[hidden email]> on behalf of Sean Breheny
Sent: Wednesday, September 2, 2020 4:55 PM
To: Microcontroller discussion list - Public.
Subject: Re: [OT] Red monochromatic LED flashlights and/or light bulbs

I doubt it is really relevant to the topic at hand (the physiological
effects of light) since the cones of the eye are not capable of
distinguishing monochromatic light from somewhat broader spectrum sources
but LEDs are not very monochromatic. I was playing around with a simple
spectrometer a few months ago and I tested a bunch of sources. Among them
were a Cree red LED, a red laser diode, and some narrow optical bandpass
filters (which I illuminated with a halogen bulb). I have attached a small
image which I hope is not too big for the listserv. It shows the laser
diode on the left, the red LED in the middle, and a 10nm-wide green
bandpass filter on the right. The laser was more monochrome than the
resolution of my simple spectrometer and shows the approximate resolution
of the device (which was just a digital camera, two razor blades forming a
thin slit, a diffraction grating, and an opaque plastic box. I
post-processed the images using a python script to produce the graphs.

Sean


[image: led spectrum.jpg]

On Wed, Sep 2, 2020 at 5:41 PM madscientistatlarge  wrote:

> P.S. afaik all leds not designed to be white or R/G/B or bicolor are
> fairly monochromatic, if I recall about 20nm half power on the curve.  Most
> of the variation in center wavelength is thermal.
>
>
>

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