Archive for November, 2014

My first LED fixture - 2004-2006

My first LED fixture – 2004-2006

This is my last bit of housecleaning from blogs being shut down, for the archives. KLW

This fixture is my very first LED light. It started life to be a halogen fixture in 2004, that sat on a workbench waiting completion. The first head got so hot from the 50W 12V light source, it was dangerous, so it sat as I decided what to do with it.

In 2005, as LEDs became viable for lighting, I pondered using them to replace the halogen source, but they delivered so little light, the end product was useless as a desk lamp, so it sat some more. One idea was to insert a Lamina BL3000 LED into the head, but the driver was huge, the light output too little, and the heat still an issue.

Then, in early 2006, while at Visa Lighting, Don Brandt (an engineer working with me at Visa, formerly from Emteq, now working at Cree I believe) were talking through ways of applying the latest mid-power LEDs using a simple PCB. We decided to give it a shot and built a board populated by a vendor with 8 Nichia LEDs. The inspiration struck to power these LEDs with two Xitanium drivers, which at the time were un-potted prototypes, so cutting them out of their housing to be installed in clear tubes to show their interiors off was easy enough. Two push-button switches activated the drivers for a high-low effect, and a heat sink was made up of a machined aluminum block installed in the head where the original halogen lamp and reflector once lived. More details and images of this can be found on the Lumenique archives for the Ratchet fixture.

The fixture itself is made of welded steel structure with a brass head and fiberglass tension springs. The head can be raised an lowered with a ratcheting action, staying level at any height. In the end, I left this fixture with the owner of the Oldenburg Group (owner of Visa Lighting) as a parting gift as I moved on to focus on Lumenique and SSL exclusively.

nikola_tesla[1]A bit of housecleaning from another blog site I am shutting down. Thought it worth keeping alive and the man in our thoughts, from 2008. KLW

If you are a fan and gear-head for volts and lighting, you have to be familiar with the guy that had a huge  influence on our modern environment. This is Nikola Tesla, an immigrant from Croatia that thought beyond direct current from batteries and heated filament electric lamps. He once worked for Edison, but found him dull and uninspired. The two inventors had dramatically different styles. Edison was the plodding experimenter, who made his discoveries through a physically iterative process in physical bench tests. Tesla was the ultimate theorist, with a capacity to thing through concepts fully, before placing pen to paper, or committing to experimentation. He constructed demonstration of light, electricity, and magnetics only after being sure in his own mind of the outcome.

Tesla brought the distribution of Alternating Current power to the world, and revolutionized industry and life as we know it today. He also brought advancement to lighting in the form of advancing fluorescent and metal gas discharge sources, at very near the same time that filament heating using direct current sources were being developed.

Unfortunately, while Tesla was a showman (he put on some amazing demos of light and electricity) he was not the publicity hound or marketer that other inventors of the era were. This set him up to be exploited by the likes of George Westinghouse, who essentially pushed Tesla aside to commercialize the AC inventions, without paying Tesla what was owed – which would have made Tesla the richest man in the world. Like the common crediting of the electric lamp to Edison,  Marconi is widely claimed to be the inventor of the radio and radio transmission. In fact, Tesla’s patent for radio transmission, awarded in 1897, predates Marconi’s improvement patents of 1903. However, using family connections and a flair for commercialization, Marconi prevailed in recognition, while Tesla remained in the background.

For anyone who interested in the fascinating period from 1800 to 1908, where the modern world was birthed on the inventors who turned us away from fire light and animal exploitation to the electric and machine age of industrialization, Nikola Tesla is someone worth investigating in detail. You will be surprised and amazed by his work, and his reclusive personality!

These links are to biographical information and additional reading and books on Telsa:

From Lucid Cafe
Drop Bears
Science World
Wiki Books
Tesla Society


Yes, Edison was a great inventor and contributor, but his position as sole inventor is a disservice to those who actually did invent the light bulbs we call incandescent today.

A little housecleaning here. I am re-posting this from one of my other blogs being cleaned out and deleted, from 2008. Thought it was worth keeping around, as this technology fades into history. KLW

While it is common folklore to credit Edison with the invention of the light bulb, the little heater-light source gadget we know as the incandescent lamp includes a long list of iterations and contributors:

1802 – Humphry Davy demonstrates first incandescence
1809 – Humphry Davy invents the first electric light, using carbon arc.
1820 – Warren De la Rue created the first vacuum lamp using platinum coil filament
1835 – James Bowman Lindsay demonstrates prototype light bulb
1840 – Warren de La Rue creates the lamp with coiled platinum filament
1845 – John Starr acquires patent for carbon filament incandescent lamp
1850 – Edward Shepard invented an incandescent arc lamp
1850 – Joseph Wilson Swan started working with carbonized paper filaments.
1851 – Jean Eugene Robert-Hudin demonstrates incandescent lamps
1854 – Henricg Globel, invented the first carbonized bamboo filament incandescent lamp.
1872 – A. N. Liodygin invents incandescent light bulb
1874 – A.N. Liodygin receives patent for incandescent lamp
1875 – Herman Sprengel invented the mercury vacuum pump to create vacuum lamps
1875 – Henry Woodward and Matthew Evans patented a lightbulb.
1878 – Sir Joseph Wilson Swan invents longer-lasting electic lightbulb using cotton carbon filament
1879 – Thomas Alva Edison invents a carbon filament in vacuum bulb
1880 – Edison improves his lightbulb using bamboo filament
, receives patent for “improved” lamp
1902 – Shelby bulb – A.A.Chaillet – long life using thick loose filament*
1903 – Willis Whitnew invented metal-coated carbon filament
1906 – Carl Schubel patents tungsten filaments (assigned to GE)
1910 – William David Coolidge invents improved process for making tungsten filaments

* 1902 entry added 10/2014 from input provided by Timothy Gravert and link to Chaillet biogrpahy.

There remains an issue of flicker and its issues that has been drawn out by a lack of action on the part of our standards and professional organizations. The topic of flicker has been turned into years of discussion, consternation, regurgitation of old information, tests to prove what has already been known for years, and avoidance of conflict. One of my best selling products from the Lumenique Product Center is the Flicker Machine, as simple device for visually detecting and confirming that visible flicker exists within a space or from a source, indicating there is a desire of individuals to know more. I presented a bit on this device and its use here some time ago.

This little spinning wheel tells the story. If you see banding and colorful rainbows, the lights are a flickerin'

This little spinning wheel tells the story. If you see banding and colorful rainbows, the lights are a flickerin’

I have invested my personal time exploring this topic, including membership in the IEEE 1789 committee addressing the risks of flicker, presentations at DOE and other conferences, working with various manufacturers on their line voltage, non-driver products, and personal testing, experimentation and actively living with and under AC LED products.  After more than 6 years of this, one simple question surfaced for me.

If DC and high frequency (>2,000Hz) PWM driven constant current LED solutions produce no visible flicker, why consider a source with greater flicker presence? (more…)

Solid-state lighting presents many opportunities to create fidelity in specification of lighting not practical or available before. Further, the blend of aggressive marketing, hype, and deception on the part of solid-state product manufacturers demands more diligent specification than ever before. The days of the conventional mode of specifying luminaires and lamps as two separate components, with experiential trust in both, is over. Today, luminaires and light sources are integral to one another, often offered up by those who have marginal experience, and a strong desire to realize sales. The only defense against predatory and overly aggressive marketing is to understand and develop a strong specification foundation. The next protective barrier is to hold that specification. The following are suggestions for building a solid-state lighting foundation for any luminaire specification, with rationalization for each consideration in practical terms. (more…)

There are many subjects in lighting, specifically in the universe of solid-state lighting, that need to be actively discussed and openly debated. Issues such as qualitative issues (color, color accuracy, glare, brightness, illuminance levels, etc..) over quantitative (lumens per watt), or the discussion of blue light content, or scotopic v. photopic, or supplier issues, or even the problems of being a small fish in a pond filled with big bloated corporate fish and a governmental agency who believes itself now a lighting expert… These all require active dialog to be resolved and grow understanding.  Too many times, the discussion of important topics are held in little rooms, hidden from view, with conclusions drawn, recommendations and regulations written – to be handed down like tablets from the mount, for us all to simply step in line and accept as fact. We have far too many instances of white paper writing scientists issuing their narrowly focused findings through their myopic peer groups, to be used as swords and weapons against the unwashed and unknowing masses. I find the creeping movement of lighting away from its roots as a human experience enhancing art-form into the hands of marketing zealots, narrow minded PhD’s working in their corporate labs, and federal or state agencies with agendas to follow outside our need to know… well, disheartening and disgusting. (more…)