There is a great deal of marketing noise professing the use of CCT white light tuning to enhance circadian function in work environments. The real question is whether this approach actually has any real-world effect on human response to light in the spaces it is being applied to.

Theoretically, the proposition is that by changing the CCT of light, one can affect circadian reaction – specifically increase or decrease melatonin suppression. The proponents of CCT tuning profess that, with no consideration of illuminance levels, cooler CCT’s will produce greater melatonin suppression, resulting in a more wakeful state, while warmer CCT’s will produce significantly less melatonin suppression, creating a more restful state that does not disrupt sleep cycles. The assumption is that illuminance levels required for proper task performance can be maintained, relying solely on a CCT change alone to impart the desired “Human Centric” benefit.

To test this, I created a test box that houses 5 different high CRI LEDs, with a dimmer. The CCT’s I chose are the popular 2700, 3000, 3500, 4000, and 5000K. All had >88CRI and >90Rf/94Rg (using TM30). The first test was to set illuminance at 50Fc, and measure the difference in Circadian Stimulus (RPI/LRC method), and Melanopic Lux (Well Buildings Standard). Read the rest of this entry »

Found the Timer

Posted: November 14, 2018 in Light Cure
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Update on the timer search:

While the response from the call-out here did not return anything from the lurking electronics gurus of the inter-webs, I was able to find a supplier here in the USA (Kentucky) able to make exactly what I needed. The company is called Curious Technology, and the individual that came up with the solution is Greg Cunningham.

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The Timer

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The String of Light

Posted: November 9, 2018 in Art and Design
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The lighting industry is a faceted and muti-layered universe. However, the bond that holds it all together is that lighting exists only to serve human kind. To the consternation of technologists and engineers behind the SSL revolution, humans (other than those in the are in the business of engineering and technology) are not particularly concerned with metrics, formulas, or objective measurement. Humans are emotional animals, that respond to light and shadow, who feel before they see, and absorb what they see as real, even when it isn’t. To this end, artistry in light remains a strong factor in the human condition, even when those experiencing it are unable to express its influence, or even acknowledge its impact. This underlying reality is what causes so many metrics addicts to go mad, as they attempt to quantify and control a market that is in fact, uncontrollable. The illusion of control is the fallacious reality we live in as humans. We cannot express our needs for an emotionally, soul energizing, comfortable or pleasing existence in metric terms. Read the rest of this entry »

Are you an electronic wizard looking to solve a small problem in your sleep? Well, this might be just such a project for you. I need help solving a problem for a product we make under our “Tasca” brand.

We are in need of a basic, robust circuit design we can make (potentially using through-hole devices) to create a simple timer as shown below. Read the rest of this entry »

Bedroom

The Great Blue Light Panic Keeping Some Folks Awake

If you read alarmist comments on the inter-webs about the dreaded “Blue Light Hazard”, you may come away thinking that your TV, tablet, phone, and LED bedside lights are depriving you of sleep. Yes, the spectral power content, including blue light, can produce amplified melatonin suppression that can indeed disrupt your ability to fall asleep. And, yes, LED lights and many LED based displays do produce blue light at the wavelengths of greatest concern. We’ve been all over this, like here, and there have been thousands of other discussions on this everywhere, including in mainstream media – which for the most part get it all wrong. Read the rest of this entry »

EMF: Another Outrage Fizzle?

Posted: September 18, 2018 in General Commentary

There has been a bit of a to-do about EMF emission from LED products on the usual outlets carrying SM punditry.  The alarmist assert that EMF from lighting products is harmful to human health, and the EMF emissions from LED light sources is damaging to the eye.

Some of this may be founded on studies like ‘Electromagnetic Field Radiation and Your Eyes‘, published on the EMF-Health web site, which references ‘Scientists Link Eye Cancer to Mobile Phones‘ and ‘Cell Phone Radiation May Cause Visual Damage‘.  Another expert warning of EMF and electronic devices is Dr. Mercola, who wrote ‘The Real Dangers of Electronic Devices and EMF’s‘. Read the rest of this entry »

Flicker is a persistent and frustrating issue, and has been since the first fluorescent and HID lamps were put in service. Complaints of headache, migraine, feelings of ill health, and eye strain are the most common complaints. For some, flicker at 100Hz (Europe/Asia) or 120Hz (North America) is debilitating. Studies have shown that flicker creates reading errors from rapid eye movement changes under sources flickering at under 200Hz – NCBI The effects of flicker on eye movement control, Energy Focus Presentation ‘Lighting Flicker: Effects of Flicker in the Classroom’, including roadway effects – Lux ‘Street light flicker is a new hazard, says watchdog’, CBC – ‘Calgary seizure sufferer worries flickering LED street light will break down again‘.

I will not go into a great deal of detail here on the effects of flicker on human health or the environment. There are hundreds of articles on this topic, by experts in human Read the rest of this entry »