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. Continue reading “The String of Light”
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. Continue reading “Bedroom Lighting for that Restful Sleep”
While designing cool lighting products is fun and all that, there are other areas of lighting development I am involved with. Whether it is UV curing of resins and plastic parts, inspection lights, or special single spectrum light sources and task lighting, it all comes under the umbrella of lighting for me. In this case, it’s about light measurement, particularly in an easy to use, and simple to set up for gathering data for use during product development, as well as verifying and evaluating design changes in process.
While large scale, accredited LM-79 photometry demands the use of expensive and sophisticated test gear beyond the reach of most organizations smaller than a conglomerate, a great deal of accurate data can be gained from simpler platforms. In the past I created a simple desktop Type C goniometer for customers who were creating small light source scale products.
Since then, I’ve built others with similar purpose for manufacturers setting up in-house test facilities on tight budgets. Having access to a goniometer, where tests and experiments can be carried out as part of in-house design operations can be a very valuable tool. It is also an excellent tool for quality inspections, and establishing variations on test results obtained from accredited labs.
For this specific instance, the requirement was for a system for testing fixtures that might be as large as 24″ in height, and up to 48″ in length, with intensities ranging from small low power sources to high intensity optically focused products. The design is basically the same as for the desktop unit, but scaled up to accommodate the larger scale of the luminaires to be tested.
Note that this is a horizontal Type C, which rotates the fixture around a fixed vertical axis, as well as the horizontal axis. This is a common approach to general lighting products, and can produce Type B results as well. However, since every test fixture is mounted with the light source aimed horizontally, including downlights, the results need to be revolved in creating usable IES files to reflect the actual luminaire orientation in use. Further, with SSL products, care must be taken to avoid including errors in light output that might result from thermal effects of mounting a vertically oriented product in the horizontal position for testing. However, in the 9 years I have been testing fixtures in this type of lab setup, I have not found this to be of significant concern. I have also devised methods for revolving the output data to create the appropriate IES formatted file for end use lighting application studies.
The other aspect of making this type of lab setup affordable, is the use of inexpensive light meters. While those in the business of accredited lab testing will scoff at the idea of using footcandle meters or hand held spectrometers for this type of application, I have found, in back-to-back testing, the results of tests done in house are within a maximum range of between +2% to -10% of those attained by independent lab testing services. Meanwhile, tests accomplished back to back between accredited labs using the same luminiares, has returned variations of +5% to -8%, while the variations in actual installed applications have been far greater due to the variance in surrounding reflective surfaces, condition of fixtures, variations between fixtures manufactured, and other factors outside the confines of the fixture designs themselves. So, while I am not saying this simple lab gear will replace independent test lab results (it won’t), I am saying that, if the operator is careful about setting up the test, diligent in detailing the data, and verifying his/her results, tests completed in-house, during design and between designs, can be reliable and valuable, and a significant cost and time saving advantage. The single largest variable that independent and accredited test labs bring to the table is consistency in process, and independent non-biased reporting for end user application. This is not always necessary for every test completed during and after designs are completed.
I have applied a wide range of meters to these types of test rigs. This includes the $100 Probe Fc meters through the more sophisticated Orb Optronix Spectrometer. The more expensive meters do deliver greater fidelity, the ability to capture multiple reading samples for averaging to eliminate error, etc.. However, I have also found that instruments like those I covered in the meter review, all delivered very similar end results. The use of the UPRTek, or Asensetek meters deliver the layer of reading color over angle in addition to standard footcandle readings, which is very useful in LED fixture evaluation. To create a candela distribution table, I use MS Excel and some simple inverse square law calcs.
For this latest creation, I have includes a rail based meter mount, as well as a rail for the vertical fixture platform. This makes setup much easier, in that moving the meter and the luminaire mount along the rails maintains alignment of the two to one another. Rotation of the luminaire in the vertical and horizontal axis is accomplished using CNC mini-mill rotary tables, actuated by remote control. These can be rotated in increments as small as .006 degrees, with 2.5, 5 and 10 being the most commonly used. The vertical axis rotation table is mounted to a large diameter rotary bearing, which can support 600 pounds.
This latest rig I also includes alignment tools. One is mounted to the center of the fixture horizontal axis (a modified rifle bore sight) aimed at the center of the meter’s receptor window. The other (contractors laser line tool) is located on the rail below – emitting a vertical line for checking the zero position of the vertical axis rotating table. With these two in alignment, the rig is set to go. Mount the fixture using adapter plates to the horizontal axis, set the optical source to the center of the vertical axis, light it up and the temperature to stabilize, and start testing. A typical test for in-house use can take less than 20 minutes after the fixture has reached its operating temperature (2 to 24 hours to taste).
There are other small additional components involved. I personally like to connect the test products to a reliable power source. The easiest way to gain this is using a UPS generally used to connect computers to. They are affordable, and offer much more reliable and consistent voltage output than wall plugs do. I also add temperature measurement (a simple Amp two position meter works for most applications – one for ambient, one for fixture hot spot), and in some case room heaters or coolers to attain a stable ambient temperature where this is not inherent to the lab itself.
So that’s it. An affordable in-house Type C test rig. Not a light source, but related to development of them. I use a similar setup for my own product development, along with a cannon style integrating chamber, a small integrating sphere, and some other cobbled together test rigs that have proven to be accurate for relative comparison of results to a known standard.
The use of LEDs in agricultural applications is expanding along side visual light and light cure technologies. The technology is even more compelling here for its reduction in energy consumption and lack of heat in the light pattern. The key element of LEDs in this application is the ability to create a specific spectral power profile, with none of the peripheral light unnecessary to get the job done. The light plants need is not the same as human vision. In fact, it is almost the opposite. While we humans with our juice camera eyeballs respond to light in the yellow-green spectrum to see by, our blind little green friends use light in the red and blue ends of the spectrum to activate various chemical reactions to generate food, build cells, and dispose of waste. Continue reading “YOL 2015 – D12 Growth Starter Light”
Actually, this started as a rough lab test experiment applying thermal transfer pipes (copper pipes filled with water) to move heat from an LED platform to a simple back plane surface. The experiment included bending the pipes, soldering them using silver bearing solder, and operating the system at various angles to see the effect these had on performance. Somewhere along the line, an idea formed of making this into a wall piece, creating an industrial-chic, which led to adding a cut down reflector, and using the SLA printer to create an industrial tech representation of a flame rising from the reflector. The square cut in the diffuser aligns with the connected graphic on the back plane, and the stenciled number 15 simply represents the year.
The driver is housed in the FDM printed housing below the light source on the back plane, with a dimmer. Total power to the source is 19W, while the LED is 95CRI 3000K. Note that the overly red hue to the background, and slight magenta appearance of the white graphics are all issues with the camera dealing with the red-enhanced LED source, which creates high CRI, with a 90 R9 value, but in reality is a distortion of spectral power that the human eye does not readily see – but mid-range camera image sensor algorithms cannot accommodate.
With the arrival of spring, I am once again longing for a rip on the open road and a little wind in the face with the rap of a high strung 4 banger UJM hot rod under me. But, let’s apply a little context as it relates to this years 52/52 project. While the previous works pursued in 2010 were focused on off-the-cuff works, with the majority being task lights, this year I am not remaining within those narrower bounds. For 2015, I’m going to present application of LEDs and SSL technology wherever I find a place for it, in actual applications, including, but not limited to lighting applications. There is a simple reason for this. My interest and pursuit of solid-state lighting integration is not bound to architectural lighting, it also includes UV curing and artistic application and, in this case, recreational uses.
Over the last several years I have been on a quest to convert all of the incandescent lamps out of an ongoing WIP motorcycle project. It seemed simple enough, as there are many made in Asia LED products sold through motorcycle retailers. The problem is, when you dig into them, they are either complete junk, weak performers, or did not fit the design of the project in hand. Nowhere did this become a major challenge more than the headlight. Motorcycle headlights serve two purposes – to light the way at night, and to create a daylight presence that catches the attention of motorists who are blind to bikes (some of the more mentally challenged motorists in this world see what they expect to see – which are cars – they are literally blind to seeing bicycles, motorcycles, animals, etc… so run over, drive in front of, and crowd these invisible obstacles out of their path.)
Compounding the issue of effective forward lighting, motorcycles, especially older ones like the one I am working on (1979), have fairly wimpy electrical charging systems, so voltage delivered to headlights tends to sag, delivering less light and warmer CCT’s. It seemed a perfect fit for application of LEDs operated from a current control driver, as this could eliminate the output droop from voltage drop, as well as increase the CCT of the light output to optimize visual performance and presence on the road. Unfortunately. sifting through the myriad of garbage being sold as LED H4 lamp replacements took some time, and included evaluation of several alternatives, many deemed useless scams. I discovered that without some form of cooling system, the LED bulbs either were not delivering enough light, or were operating at such a high temperature, they were likely to fry themselves and fail in less time than the halogen lamp I sought to rid myself of. However, over the course of this winter, several new lamps came into the market that are looked promising. While not yet perfect, I found one that not only fit well, but delivered more light than the original halogen lamp. I was finally able to finish the LED conversion project this week, ending a two-year effort at last. The new system presents a load of 12W or 14W, replacing the 55/60W H4 Halogen lamp, while measured light output is increased by 15% (at full battery voltage, significantly more when the battery voltage is lower). The lamp includes an active heat sink and fan to keep it cool, which I found in bench testing worked surprisingly well. In fact, the thermal slug-to-heat sink is very similar to a design I have used in several product designs with similar optical demands. Not really wild about the fan, so will keep an eye on that, but its necessary to produce the output and longevity I was looking for.
In addition to forward , the headlamp integrates the turn signals. At the right and left side are amber LEDs embedded into the lamp reflector, which serve as turn signals and emergency flashers. At the center is the H4 LED conversion lamp, which incorporates a current driver, cooling fan, and controller circuiting that maintains full light output, even when battery/system voltage drops to as low as 9.8V. The tail-light includes red LEDs and a controller that and white LEDs with a clever resister/bypass circuiting that lights all of the LEDs at a lower intensity for standard tail-light function, then brighter when the brake light is active. The rear turn signals are a Frankenstein creation of mine that includes custom interior bits to integrate proper Amber LEDs into the bullet shaped housing originally designed for a small incandescent lamp – I was unable to find any off-market products that had the brightness I wanted.
The turn signal conversion to LEDs created an issue with the flasher system. Flashers in older vehicles are nothing more than a thermal cutoff switch that auto re-sets. When on, an internal leaf or coil heats up, breaking the circuit (off state), which then cools quickly and re-connects (on state). These are “tuned” to operate with a closed circuit, which an incandescent lamp provides. The load of the lamps in the circuit creates a resistance, which the flasher is tuned to, creating a flash rate based on how much voltage is present in the system based on how many incandescent lamps (acting like resistors) are in the circuit. This is why the flashers blink faster when a lamp is lost – increasing the voltage in the flasher “heater”, causing it to heat faster, thus, blink at a faster rate. Well… LEDs do not create a closed circuit for this process to work with. This requires either placing a resister into the system to create a closed circuit load similar to the original incandescent lamps (seems kind of silly), or replacing the flasher itself with some other modulating device that can blink without the closed circuit connection. Motorcycles present a few odd wiring flukes that complicate this, so the solution requires a little custom hacking. In my case, I was able to find a flasher kit from an on-line electronics kit outlet, that was then modified to work within the bikes wiring system. Problem solved.
In the end, the compelling reason for this entire conversion included several desired advantages. Incandescent lamps on vibrating motorcycles is a bad thing, LEDs don’t suffer this malady so no more constantly burned out bulb issues. Incandescent lamps present a load to relatively feeble motorcycle power and charging systems. The LED conversion reduced the load on the charging system and battery system from 94W to just 26W total, which allows the charging system to be used by the ignition system, at a more constant output voltage – while delivering brighter lights all around, and decreasing the time it takes to recharge the battery after starting. The LED headlamp conversion also increased the headlamp CCT from 3150K to 6500K, which is more visible during the day to numb-skull cage drivers, and increased visual performance while riding at night.
With this conversion, I am now down to just a few CFL and T8 lamps in the shop and garage, and just (2) halogen/filament lamps remaining in my home and work spaces. These will soon be gone as this years 52/52 projects puts them in the cross-hairs. Stay tuned….
My involvement in lighting was born from a graphic arts and photography background, so imagery remains a core interest of mine. Design 9 was inspired by a particular image of a rifle scope being shot through by another rifle, creating an eruption of glass that caught the light. We’ll get to the reason this was being photographed, and why in a moment. First, what intrigued me was how high speed photography today catches moments in time that are beyond human comprehension. We are blind to most wavelengths of energy, we know that. But, what we seldom recognize is that the slowness of our visual processor is such that we comprehend only a fraction of what is actually happening around us. Time lapse and high speed images catch a fraction more of this missing perception. Time laps images capturing the blooming of flowers, showing that these organisms live in a slow motion universe outside our comprehension. High speed photography shows us the micro-moments that occur while our feeble brains process sampling of bits.Continue reading “YOL 2015 – D9 A Piece for Optical Conversation”
As demonstrated in D1 of this series, LEDs and solid-state technology are changing more than general illumination. Other instances of applying near UV LEDs with emission to cure light-cure resin composites. We have applied this to replace Metal Halide light sources that require 20 minutes to start-up, and are skin frying monsters. LED cure lights are also more predictable and focus-able than natural light, and can be applied indoors, and less bulky and more powerful than fragile fluorescent cure systems. LED sourced cure lights are now used in printing, dentistry, and commercial production of resin-based composites. We are also applying this on small and large scale applications from the very small (like D1 SLA curing) to larger scale units for curing large objects, like fiberglass repair of boat hulls, custom automotive body panels, and low odor repair of fiberglass bathtubs and shower floors. The use of LEDs produces instant-on high intense light, with much less power, significantly less heat in the lighted pattern, less exposure to hot surfaces, and contain none of the damaging ultraviolet light that does nothing to enhance curing, but is harmful for operators. The use of UV initiated resins offer the advantage of extended shelf life as there is no catalyzed resin to harden in the container and less odor for use indoors. An update with new images and details will be posted here when available.
I found this little light on ebay at a lunch money price, so couldn’t resist. It started life as a Hamilton Industries (Chicago) lamp model 60, made in Japan in the early 1960’s. It used a 12V magnetic transformer and a resister to provide a dual level light control of its 20W signal lamp. The amount of light it put out was barely visible in the presence of any ambient light. Meanwhile, I had a cute little key-chain wireless remote controller for less than $14 from LED Supply that delivers PWM dimming and on-off control of 12VDC LED loads. I stripped the guts out of their kit and put them inside the base of the fixture. The little lighting head was about the right size for a 12V MR16 lamp, so rather than re-invent that wheel, I just retrofitted the head to take a bi-pin socket and planned to use a retrofit MR16 lamp to deliver the light I wanted. That ended up more of an issue than I expected. First, after testing of all the LED MR’s I had around, only one brand would operate and dim effectively when run on DC power. The rest were poor dimming on AC power, but on DC they were miserable. On the LED Supply remote dimming module, they were useless. The lamp I ended up with was a Philips Enduraled product, and it will dim down to around 10%.
The remote control is a bit of fun, as it has an antenna that works well with the antenna arm on the fixture, so they seemed a great match. I printed a holder for the face of the power supply (now control) enclosure at the base of the fixture to hold the remote, which makes it a simple panel controller when the remote feature is not needed. When the light is used to wash a wall or light art or some other function besides a desk lamp, the remote can be removed and control the fixture from across the room. The power supply is a simple 12VDC wall wart, while the base houses only the remote control electronics now.
The base looked in need of a bit of dressing up, so I printed a retro-turbo trim ring to surround the remote control mount on the SLA printer and painted it with VHT fake chrome to give it a sand-cast aluminum look. I also printed the same part on the FDM printer for comparison. I’m throwing in two images of the raw prints to show the difference in surface quality one gets between these machines. Obviously, for parts that include details that will be hard to sand and fill, the SLA process is superior. For parts that need to be strong and can be easily finished, the FDM is the go-to tool.
So, this little weak black egg ebay find has been transformed from a barely functional desk lamp novelty, to a bright, useful, remote controllable, dimmable, black egg turbo trimmed LED light novelty. I’m a fan of the 50’s and 60’s design aesthetic, so this one felt right and was fun to put together.
I am a task lighting fanatic. I use them everywhere, so am always looking for something new to add to my collection. In this installment, I am addressing the need for a light that is compact, delivers intense light (1,200+ Fc) with no glare or brightness, and high color accuracy. The application is pretty straightforward, from soldering station use where a magnifying glass is used, to fine detail work inside or on the outside of models. For good measure, I also wanted it to aim at the wall as a photo fill light, or straight up as am ambient fill light, and have a dimmer to allow me to set whatever level I want for the application in hand at the moment.
With all the practical specifications set out, I decided to let this design be expressive of the gadgetry involved. Let it all hang out. I also decided to incorporate the new Bridgelux Vero LED with its integrated Molex connector, and a Nuventix cooler, just to amp up the tech factor. This is where things got interesting. The Bridgelux array operates at 33.7V (500mA). The Nuventix cooler at 12V. I am powering the whole thing with a 24VDC wall wart power supply. That meant I needed to employ a boost driver for the LED and a buck (24VDC to 12VDC) power converter for the Nuventix cooler. I used Recom components to attain this, and used a cut up experimenters printed circuit board to connect these two to the power supply, the cooler, the LED and the dimmer control. That’s a lot of wires to find a path for, so I decided to leave them to roam free, let everyone see the components as well.
This is a style of design I personally enjoy, and have been doing since the 1980’s, where we made little 12V lamps with fiber optics, MR16s, halogen burners, or automotive headlamps, often suspended from structures made of building wire. In this case, the stand I found at a Goodwill. It was a table lamp, whose shade was gone, and socket was cracked. I liked the cast iron base and single post stand, so nabbed it for a dollar and tossed it in the pile with my other finds, waiting this moment to be put to service.
If you look at the head, the switch is a sliding action, on the left side of the head. Pull it forward to turn it on, push it back to shut it off. A hole in the side of the housing allows you to see the action inside. No, there is no reason for this, other than it seemed more appropriate than an off-shelf toggle or twist switch.
The light on the task surface is at 1,425 Fc, the LED is 3000K, 97CRI.