Posts Tagged ‘SSL’

The retro black egg - origins unknown.

The retro black egg

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 acts as a panel control when nested in the base, and as a remote control with cute antenna when separated.

The remote control acts as a panel control when nested in the base, and as a remote control with cute antenna when separated.

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 now incorporates the remote in a recessed compartment.

The base now incorporates the remote in a recessed compartment.

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.

The lighting head uses an LED MR16 lamp for its optic and driver components

The lighting head uses an LED MR16 lamp for its optic and driver components

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.

The turbo fins look very rocket-man when the egg is closed up

The turbo fins look very rocket-man when the egg is closed up

 

 

 

 

 

 

 

The remote facilitates using the light as a wall accent, or ambient uplight, controlled from elsewhere in the room

The remote facilitates using the light as a wall accent, or ambient uplight, controlled from elsewhere in the room

With the remote out, the light can remain on, lighting the turbo louver as a night light

With the remote out, the light can remain on, lighting the turbo louver as a night light

The ebay purchase

The ebay purchase

The cord was ugly and the closed appearance rather out of alignment and boring

The cord was ugly and the closed appearance rather out of alignment and boring

While FDM 3D printed parts (top_ are strong and easily finished, in fineer detail work, they lack fidelity and smoothness. The SLA (bottom) part is much smoother, requiring less finish work, but are less durable. In this case, the FDM is printed at its finest setting, the SLA at its coursest, so the contrast here is greater when the SLA is pressed to maximize reolution. Both took 2.5 hours to print.

While FDM 3D printed parts (top_ are strong and easily finished, in fineer detail work, they lack fidelity and smoothness. The SLA (bottom) part is much smoother, requiring less finish work, but are less durable. In this case, the FDM is printed at its finest setting, the SLA at its coursest, so the contrast here is greater when the SLA is pressed to maximize reolution. Both took 2.5 hours to print.

 

The Purple Light ‘UV’ Cure Cube

The Cure Cube is used for curing SLA 3D Prints created on the Form Labs 1+ printer. Exposing SLA prints to 405nm "UV" light increases strength and creates a harder surface for final finishing.

The Cure Cube is used for curing SLA 3D Prints created on the Form Labs 1+ printer. Exposing SLA prints to 405nm “UV” light increases strength and creates a harder surface for final finishing.

While not particularly visible to everyone in the SSL universe, over the past few years one area of interest in LED product development for me has been in use of 405nm LED light sources to cure various plastics materials. The advantages are lower power requirements and reduced overall heat in the cure zone over conventional fluorescent or HID light sources. This has been of particular interest in curing fiberglass resins manufactured by Sunrez. The typical demand is for between 200 and 1,000 µW/CM² at 400-405nm wavelength. The use of LEDs allows us to generate exactly that without the waste of visible light, and longer wavelength power the resins are not reacting to. In one project, we were able to replace a 1,500W HID light source with a 120W LED light system that produced faster cure times with less than 10% of the total power, and virtually no heat added to the heat generated by the resin’s exothermic reaction to the curing initiator. Since then, we’ve built 405nm light cure fixtures ranging from 1,200W to 25W.

In this case, I needed to cure 3D prints we generate on a Form Labs 1+ 3D SLA printer, and do so in an office environment without exposing other materials and occupants to UVA light output. The material used in the print process is acrylic based, with chemistry that is photo-reactive to 405nm. The actual prints are made using a UV laser source. When the part is removed from the printer it is washed in alcohol (91% IPA), rested for a few hours to dry the alcohol off, then placed in this cure cube for an hour or more, depending on the thickness of the final component. The end result is a hard first surface for finish sanding or painting, if necessary, and a more rigid part as a whole (less flexible).

The cube is simple, with vent reliefs top and bottom to encourage ariflow. The flush switch on the top cover was created using 3D printing processes for the slider and body, as well as top and bottom cover.

The cube is simple, with vent reliefs top and bottom to encourage ariflow. The flush switch on the top cover was created using 3D printing processes for the slider and body, as well as top and bottom cover.

The cube utilizes a simple aluminum housing, with FDM 3D printed top and bottom covers. The top cover houses a single Recom 500mA driver, slide switch and wiring terminal block on a Tasca LED driver circuit board.

5mm 450nm LEDs with a FWHM distribution of 60º, 25 per side and top (125 total), operating at 20mA each, mounted to custom circuit boards sourced at Express PCB. Each board connects the LEDs in parallel, while the boards are connected in series, resulting in a 500mA, 15.4V circuit, totaling 7.7W. The boards and internal exposed surfaces inside the box were then covered with White Optics 98 matte material to increase total light energy and diffuse The light energy at 405nm is roughly 600 µW/CM².

The bottom surface includes a glass plate where the product sits in order to make any possible stickiness of a part from adhering to the White Optic material below.

The interior of the cube is covered with White Optics 98 material for optimizing light energy re-cycling.

The interior of the cube is covered with White Optics 98 material for optimizing light energy re-cycling.

The housing was powder coated matte black polyester to make clean up easy and the box look nice. The overall interior dimensions of the box are 1″ larger than the total build volume capacity of the printer itself (5 x 5 x 6.5), as any over-sizing is unnecessary. This produces an optimal match between the location of the LED sources and any part the printer can produce.

The Cube is powered by a remote plug mounted 24VDC power converter.

The operation of the box is simple enough. The box is lifted up, the part is set on the base, the box is set over the part, and the light is turned on by sliding the switch to the on position.

Simple and compact is the order of desktop manufacturing, and this fits that model perfectly.

A look into the box lighted up and ready to accept parts.

A look into the box lighted up and ready to accept parts.

Testing so far has shown the cube can cure raw resin from liquid to fully hardened in less than an hour, and strengthens prints in that time or less. The heat generated from this arrangement is so small, there is no chance of any part being warped or affected by the process, other than the desired results of becoming stronger.

For parts to be left unfinished, that are desired to be used over extended periods, we coat the finished parts in either acrylic or polyurethane UV inhibiting clear coat, gloss or matte. This stops ambient room light or daylight exposure from making the parts brittle over time. I am building a second copy of this cube for completing extended testing of samples of the materials we are using to verify clear coat effectiveness, behavior of the print material over long exposure periods, and the behavior of these low cost LEDs over time. A commercial version of this cube could be made using more robust LEDs, but the costs would be significantly higher as well. In the current configuration, the LEDs only cost $0.60 each, so should they last a couple of years in use, replacement of the populated boards is a simple task, while the cost of higher power LEDs would have increased the cost of the entire end-product by as much as three times.

There is also an additional version of this same approach in using Red/Blue light sources for use in plant seedling starts. We’ve found tests with common rye and barley grasses, the time from germination to hearty growth ready for planting is accelerated significantly. Using an enclosure like this allows the plants to be exposed to intense light for extended periods of time (18 hours or more) without polluting the surrounding environment with the ugly light, just as the enclosed cube protects room occupants from exposure the the UVA light. In either case, the cube can be used in any room environment comfortably and safely.

So this gets us off the ground and is D1 of 52 in the series. As I’ve noted at the start, this is an exercise in making progress, and putting SSL to work. This is not a particularly exciting product in and of itself, but it is one that will be used regularly, which more than makes up for its lack of marketing sizzle for the masses – at least in my book.

 

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…)

In my previous entries regarding the Cree LR6, I’ve noted the good and bad sides of the product in some detail. I’ve noted my dissatisfaction with the brightness of the diffuser, which has caused me to first apply plastic trim rings to add a little cutoff, then later, to simply not turn them on. Dimming performance over the years has been disappointing as well. No dimmer I have found has dimmed them satisfactorily, most cause them to flicker. The latest from Lutron, designed specifically for LED/CFL sources, did not fix the issues, so I simply gave up. Rather than remove these expensive retrofits ($65.00+ each), I chose to do what many of us do when caught in a  quandary – stopped using them at all. Estimating these were not used more than an average of 1 hour a day for the last 4 years, total operating time is less than 1,500 hours. I’ll give them 2,000hrs, assuming that when they were first put in place, I used them more than I did as we grew tired of their glare and flickering under dimmer control. (more…)

For anyone interested in saying hello in person, to knock ideas around, or just tell me what you think of things, meeting up at a conference is ideal. Since I try to bring original content to each venue, the time it takes to put a presentation together is enough that I usually limit the number of presentations to 3-5 a year. This year is about over, but I do have 3 more to go on the schedule, for anyone interested. (more…)

In a recent article published in Architectural SSL on the topic of blue light content of LEDs, I attempted to present the discussion of blue light from the perspective of those raising concerns about blue light hazards against known and practical objective knowledge on the topic. The article covered the gambit of concerns, from retinal damage concerns to melatonin levels in occupants, from both sides of the argument, as there are those who dismiss this as a non-issue out of hand. The article also forwarded two conclusive suggestions. First: The research on this specific topic, as it relates specifically to LED light sources, is a little thin. Second: For those concerned about blue light content, selecting LEDs of a lower CCT and higher CRI delivered the lowest blue light content. Whether or not this is the best choice for visual acuity was not the subject of the article, nor was it suggested as the best solution overall. There is a great deal of research supporting the concept of high CCT light for enhancing human visual performance. Much of this was completed under light sources other than LEDs, so there is no caveat included that states anywhere that blue light content of LEDs is at acceptable levels, or of no concern. (more…)

After reviewing a range of different metering choices in actual use, I compiled a summary of findings, as well as my own personal subjective ratings of features and overall utility as a lighting professional. This chart is the collection of all findings in a simple comparison table for those who find this useful (like me): (more…)