Posts Tagged ‘SSL’

Recently, there has been news hysteria about the availability of 3D printed gun plans, and the implications of such a product being made available to the general public. There are several facts that must be squared away before this “news” story can be effectively (more…)

Follow along, and see if this sounds familiar…

In the process of designing a new light, you begin by collecting manufacturer data sheets. You rifle through the LED data to find lumen output for LEDs and select one with a rated lumen output of 390@700mA, 3000K CCT / 90CRI (test current), and 188 lumens per LED at 350mA (calculated value), @ 3.4 Vf, for 158 lumens per watt. Nice!

You calculate what you need to make the target 1000 output lumens, and design a product around the data and calculations, use 7 LEDs operated at 350mA, to include 30% over the target to compensate for optical losses and temperature per the manufacturer data sheets. Using first article parts to build a prototype, you send it off to the photometric lab, expecting to see results very close to what you calculated. You can live with a minimum of 900 lumens, but hope to see better than 1000, as the data provided by the component providers indicates this should be the case. (more…)

I propose that all pursuits of a color quality metric represented in any form of numeric value based on averages of performance over any number of color samples is wholy inadequate and a wast of time. We have been using such a system for far too long, with too many questions and related surrounding quality issues unanswered to continue with such a weak approach. I suggest that we pursue a Lighting Qualities Classification system that encompass eight (8) core variables that are critical to identification and selection of lighting products. This would be represented in a similar fashion as the successful Ingress Protection (IP) rating system already in use.

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Zero Flicker Task Light

Posted: January 21, 2016 in Light Meters, Tasca
Tags: ,
The Tasca task lighting head. My pet project for more than 6 years now.

The Tasca task lighting head. My pet project for over 6 years.

 

When I created Tasca, I had several goals in mind:

  • Strong light output  – Check – 800 lumens is top of its class
  • Smooth wide light pattern – Check – 78 degree beam pattern with no hot spots, no streaks, no rings, >200Fc at 18″
  • High color performance – Check >80CRIe standard @4000K, moving to >90CRIe @4000 or 5000K in latest models
  • No sparkly LED arrays – Check – single high quality COB array source
  • High efficiency – Check – >70lm/W total fixture efficacy
  • Tough and Ready – Check –  examples have been in operation 24/7/365 in shop environments with zero failures
  • ZERO FLICKER – Check – see below

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The original idea for the lighted magnifier was for inspection and reading small print on tools, which are generally done in a fixed location. The intended use was for continuous periods of work that made battery operation an issue. Mainly, the initial thinking was to turn it on and leave it on for the duration of a project. So, with it in hand and in use, I found in a short time it was being used for much more than its original intent. The magnifier lens in its unlit state is excellent in capturing ambient light, so I had it in mind that one lighted unit for the very tight and difficult work was great, with an unlit version for all other tasks. Problem is, the lighted unit provides over 1,780 FC on the target, transmitting over 700 FC to the eye at 4″. The unlit version produces no more than ambient levels, and if your head shades the ambient light, that is cut considerably. So, when comparing the two in actual use, the lighted version simply knocks the stuffing out of the unlit one. This meant I needed to cut the umbilical and create a battery powered version.

Adding a battery power pack to the Magnifier was found to be a desirable addition after finding the lighted unit so useful.

Adding a battery power pack to the Magnifier was found to be a desirable addition after finding the lighted unit so useful.

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A little industrial chique tribute to 2015 Year of Light.

A little industrial chique tribute to 2015 Year of 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 graphic alignment with the diffuser negative space connects the back-plane to the foremost diffuser component.

The graphic alignment with the diffuser negative space connects the back-plane to the foremost diffuser component.

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.

The diffuser is intended to interpret a flame, or gas light sock.

The diffuser is intended to interpret a flame, or gas light sock.

 

The thermal pipes move 19W of energy from the LED platform to the back-plane - which is where the whole project started.

The thermal pipes move 19W of energy from the LED platform to the back-plane – which is where the whole project started. Cutting the back half of the reflector out provides light to the wall and plate surface.

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.