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One problem with current popular LED bulbs: They emit more blue light than incandescent bulbs [1]. If people light their households with LED lights at night, i

One problem with current popular LED bulbs: They emit more blue light than incandescent bulbs [1]. If people light their households with LED lights at night, it might shift their circadian rhythms [2]. Screwed up circadian rhythms can have all sorts of negative health/productivity effects. [1] http://www.designingwithleds.com/measuring-light-quality-philips-cree-led-bulbs-spectrometer/ http://www.designingwithleds.com/measuring-light-quality-phi... [2] https://justgetflux.com/research.html https://justgetflux.com/research.html

jrapdx3 12y ago
That thought occurred to me as well. Circadian phase delay already seems to be a problem re: the increasing brightness of our computing devices, almost all using LEDs. New phones, tablets, TV's, etc. should come with a warning to keep them "dimmed down" in the evening, or better, keep use to a minimum late in the day. Sure, I know, the odds are about zilch people would actually heed such advice, but it ought to be out there anyway. Another thing is the the relatively low CRI. For many purposes (industrial, medical, artistic) the spectral output of bright LEDs is far less than ideal. LEDs will probably get closer to "full-spectrum" over time, and no doubt will easily beat the discontinuous spectrum of fluorescent lamps. LEDs now just need to get cheap enough, and really need to work with existing dimmer controllers.
- tacoman 12y ago
  CRI (or at least what's advertised) has really improved in the last year. It not difficult to find 90+ bulbs at places like Home Depot.
- km3k 12y ago
  Yes, but there are solutions for brightness/color at least for our smartphones and PCs. Android: https://play.google.com/store/apps/details?id=com.vito.lux&hl=en https://play.google.com/store/apps/details?id=com.vito.lux&h... PC: https://justgetflux.com/ https://justgetflux.com/
joshuahedlund 12y ago
Interesting link. The contrarian in me says it only looks at a couple bulbs, and in my (limited) experience with a variety of new low-end LED bulbs the light quality varies greatly and has also been improving, so maybe this won't end up being much of an issue on circadian rhythms at all. But it's an interesting factor I hadn't been considering (how do LED's compare in this to the CFL's that have already replaced incandescents for many, I wonder?)
jp555 12y ago
Almost all the LEDs in my house are ~2700K, about the same an incandescent lights. Regarding circadian rhythm, light from near-sleep-time television watching is much more of a concern, but that's been a problem for at least 30 years.
- Someone1234 12y ago
  I'd pay good money for a TV with integrated F.lux (i.e. blue gradually degrades with the movement of the sun). I started using F.lux too many years ago now to count, and honestly it really seemed to help. However getting similar kind of functionality on all of your other devices (e.g. Tablets, Phones, TV, etc) is near impossible right now. As far as I know the "blue light ruins sleep" research is fairly decent, so hopefully it isn't a placebo.
  - poopchute 12y ago
    For Android I use something called "Twilight". It is a good stand in for F.lux, and even has a few extras. For time control, it has the standard sunrise/sunset coordinate system that F.lux uses, as well as Alarm control to set custom bedtime/wakeup.
- RoboTeddy 12y ago
  2700K can still have a spike of blue in the wrong spot. this is a 2700K bulb: http://www.designingwithleds.com/wp-content/uploads/2014/01/Cree-regular-600x294.jpg http://www.designingwithleds.com/wp-content/uploads/2014/01/...
  - jp555 12y ago
    what is the relevance of that blue spike? Incandescent spectrum looks much more linear (http://housecraft.ca/wp-content/uploads/2012/09/spectral_responses2.png http://housecraft.ca/wp-content/uploads/2012/09/spectral_res...), but appears to maybe emit more (just judging by eye) aggregate blue energy than the warm white LED. Then again intensity towards blue-green still seems much higher in the LED, and maybe that matters more?
peatmoss 12y ago
I'll be trying my hand at some LED strip / arduino programming to build a dawn alarm that goes from dim red to bright white progressively. I have a Philips halogen dawn alarm which naturally goes from orange -> red as it ramps up, but unfortunately doesn't get quite as bright as I would like for that "wake up at the cabin" experience. I'd love to see more applications of LEDs providing the right color temperature and intensity for the time of day, as well as more applications that avoid the bulb form factor. I'd love for my ceiling to emit light like the sky...
- pc2g4d 12y ago
  I'd been considering a project like this recently. I'd like some way of bringing the amount/timing/frequency of light I experience indoors closer to what I would experience were I in the outdoors, under the assumption that it would be better for my sleep/wake cycle and possibly other things.
- RoboTeddy 12y ago
  The best thing I've found so far are these lights meant for growing coral: http://www.maxspect.com/index.php?option=com_content&view=article&id=20&Itemid=21&lang=en http://www.maxspect.com/index.php?option=com_content&view=ar... One of the models puts out UV, so be careful. Message me (email in profile) if you want to chat!
  - peatmoss 12y ago
    Those look like a very polished product! In my case, I'm looking to take advantage of the availability of $15 for a 300 RGB LED strip, as well as for the challenge writing my own control logic with an arduino. The SAD wake-up alarm is more of a side-benefit.
    - RoboTeddy 12y ago
      I don't have any SAD issues, but I find that getting proper light in the morning helps stop me from going to bed too late. I like your project! How many watts is the LED strip?

jrapdx3 12y ago

That thought occurred to me as well. Circadian phase delay already seems to be a problem re: the increasing brightness of our computing devices, almost all using LEDs. New phones, tablets, TV's, etc. should come with a warning to keep them "dimmed down" in the evening, or better, keep use to a minimum late in the day. Sure, I know, the odds are about zilch people would actually heed such advice, but it ought to be out there anyway. Another thing is the the relatively low CRI. For many purposes (industrial, medical, artistic) the spectral output of bright LEDs is far less than ideal. LEDs will probably get closer to "full-spectrum" over time, and no doubt will easily beat the discontinuous spectrum of fluorescent lamps. LEDs now just need to get cheap enough, and really need to work with existing dimmer controllers.

tacoman 12y ago
CRI (or at least what's advertised) has really improved in the last year. It not difficult to find 90+ bulbs at places like Home Depot.
km3k 12y ago
Yes, but there are solutions for brightness/color at least for our smartphones and PCs. Android: https://play.google.com/store/apps/details?id=com.vito.lux&hl=en https://play.google.com/store/apps/details?id=com.vito.lux&h... PC: https://justgetflux.com/ https://justgetflux.com/

joshuahedlund 12y ago

Interesting link. The contrarian in me says it only looks at a couple bulbs, and in my (limited) experience with a variety of new low-end LED bulbs the light quality varies greatly and has also been improving, so maybe this won't end up being much of an issue on circadian rhythms at all. But it's an interesting factor I hadn't been considering (how do LED's compare in this to the CFL's that have already replaced incandescents for many, I wonder?)

jp555 12y ago

Almost all the LEDs in my house are ~2700K, about the same an incandescent lights. Regarding circadian rhythm, light from near-sleep-time television watching is much more of a concern, but that's been a problem for at least 30 years.

Someone1234 12y ago
I'd pay good money for a TV with integrated F.lux (i.e. blue gradually degrades with the movement of the sun). I started using F.lux too many years ago now to count, and honestly it really seemed to help. However getting similar kind of functionality on all of your other devices (e.g. Tablets, Phones, TV, etc) is near impossible right now. As far as I know the "blue light ruins sleep" research is fairly decent, so hopefully it isn't a placebo.
- poopchute 12y ago
  For Android I use something called "Twilight". It is a good stand in for F.lux, and even has a few extras. For time control, it has the standard sunrise/sunset coordinate system that F.lux uses, as well as Alarm control to set custom bedtime/wakeup.
RoboTeddy 12y ago
2700K can still have a spike of blue in the wrong spot. this is a 2700K bulb: http://www.designingwithleds.com/wp-content/uploads/2014/01/Cree-regular-600x294.jpg http://www.designingwithleds.com/wp-content/uploads/2014/01/...
- jp555 12y ago
  what is the relevance of that blue spike? Incandescent spectrum looks much more linear (http://housecraft.ca/wp-content/uploads/2012/09/spectral_responses2.png http://housecraft.ca/wp-content/uploads/2012/09/spectral_res...), but appears to maybe emit more (just judging by eye) aggregate blue energy than the warm white LED. Then again intensity towards blue-green still seems much higher in the LED, and maybe that matters more?

peatmoss 12y ago

I'll be trying my hand at some LED strip / arduino programming to build a dawn alarm that goes from dim red to bright white progressively. I have a Philips halogen dawn alarm which naturally goes from orange -> red as it ramps up, but unfortunately doesn't get quite as bright as I would like for that "wake up at the cabin" experience. I'd love to see more applications of LEDs providing the right color temperature and intensity for the time of day, as well as more applications that avoid the bulb form factor. I'd love for my ceiling to emit light like the sky...

pc2g4d 12y ago
I'd been considering a project like this recently. I'd like some way of bringing the amount/timing/frequency of light I experience indoors closer to what I would experience were I in the outdoors, under the assumption that it would be better for my sleep/wake cycle and possibly other things.
RoboTeddy 12y ago
The best thing I've found so far are these lights meant for growing coral: http://www.maxspect.com/index.php?option=com_content&view=article&id=20&Itemid=21&lang=en http://www.maxspect.com/index.php?option=com_content&view=ar... One of the models puts out UV, so be careful. Message me (email in profile) if you want to chat!
- peatmoss 12y ago
  Those look like a very polished product! In my case, I'm looking to take advantage of the availability of $15 for a 300 RGB LED strip, as well as for the challenge writing my own control logic with an arduino. The SAD wake-up alarm is more of a side-benefit.
  - RoboTeddy 12y ago
    I don't have any SAD issues, but I find that getting proper light in the morning helps stop me from going to bed too late. I like your project! How many watts is the LED strip?