Posts Tagged ‘LED’

Bridgelux has announced the End of Life for the BXRA product. This is the product that put this company on the map, and has been very popular. The company is now hawking its me-too product platforms, along with its proprietary Vero product. I for one will never again consider a proprietary platform from Bridgelux. I am also sure they will experience a significant number of defections as customers find their way resolving the disruption the end of the BXRA platform will cause. I know this, as I intend to help every customer of mine, and anyone else interested, to find a path to other provider products.

When Bridgelux came onto the market, it professed to know the architectural lighting market, making bold statements about how it would support its customers with consistent products with little or no platform obsolescence. O bought it. Cree has done this, so it was no stretch to believe Bridgelux could make good. They were also touting themselves as a U.S. company, invested in the U.S.A. Yet, over the last several years, they have proven that all that blather was just marketing farf. They’ve made regular product changes that have demanded redressing driver selections, not to mention changes in fV and max current limits that have fouled up UL listings. They have walked out of the U.S. market as a manufacturer. Now they are owned by the Chinese CEC company, and have completely turned their back on past promises to serve their customers with the product stability. I have promoted this company to customers, and use it in my own Tasca products. That ends with the demise of the BXRA3.

At the core of this seemingly small issue of planned obsolescence, is the impact these changes will have on hundreds of customers, effecting thousands of end products, including UL and photometric test implications that will result in a lot of cash being spent in response to this discontinuance. The underlying issue is that BXRA ES and RS arrays once presented a unique combination of voltage and current that created unique driver configurations different from their competition. For most, changing to any other COB will require redressing driver selection, which will demand UL changes. For some, the implications are going to be significant. For example, in some products I am directly involved with, the power supply is 24VDC, with buck CC drivers connected to the LED. That is no longer possible using any of the new COBs from Bridgelux. Cree, thankfully, has a few options that will limit the damage to some degree. For others, the open circuit voltage of higher fV drivers will create a mess with LED holders that have exposed metal contacts that UL will insist be covered, demanding changes that will likely lead to re-testing. And, for many, the impact on optics is going to be a long and hard road to travel. Changing the array to a new platform will require new optics be sourced, and since these are not exactly the same as the outgoing combination, new LM-79 testing will need to be done. This is all going to have to happen NOW, as the announced EOL is immediate, with the last products available for order in mid June.

The saving grace in all of this is that the replacements Bridgelux offers are not significantly unique in voltage, current limits, lumen output, color, or general size/configuration from what is available from many others today. That means that when customers are faced with the disruption of re-configuring their products to the higher fV/lower current requirements,  and new optics, they can consider pretty much all competitive products to protect themselves from any future recurrence of changes in any one proprietary configuration the end of the BXRA platform presents. Since the new configurations will require updates, if not completely new UL testing, and likely new photometric testing, I strongly recommend that every Bridgelux BXRA customer cross their requirements over to at least three providers. Cree, Samsung, Citizen, and Luxeon now all make very strong performing products that can stand up against anything Bridgelux offers – with the same core fV and current combinations  to attain equitable output. This, combined with the range of Zahga compliant LED holders and associated optic accessories, pretty much means the proprietary Vero series is a non-starter – except for those that are Zahga compliant.

I personally will not update with Bridgelux new products. For my own products, we are black-listing Bridgelux for its inconsistency between what it says it is doing and going to do, and what it actually does – often with very short notice given. My continued strong support for the company ends with the BXRA platform EOL. It is the perfect opportunity to break away from them and move forward with new providers, and I intend to take full advantage of that. This saddens me in some way, as I have had so much fun and enjoyed building products around the BXRA. This is the end of a very short lived era for me.  When Lumileds ended the K2, the backlash was severe. I expect that Bridgelux is going to experience much the same with the ending of its BXRA ES and RS arrays. I’d wish them luck, but can’t find it in me to be that polite. This situation stinks, on so many levels that its hard to be calm about it. At a time many are finding their feet after being pounded by the cost of SSL development and a soft economy, to now face redressing products already in demand and on sale, caused by manufacturer planned obsolescence – means nothing of value is gained, and a lot of unnecessary cost will be incurred.

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.

This goniometer delivers a simple to use platform for in-house testing of a wide range of luminaire configurations

This goniometer delivers a simple to use platform for in-house testing of a wide range of luminaire configurations. The meter can be located anywhere from 24″ to 96″ from the optical center of the luminaire.

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.

An earlier example of a bench-top system was designed for testing of small light engines and LED optics, shows the same basic configuration in smaller scale.

An earlier example of a bench-top system was designed for testing of small light engines and LED optics, shows the same basic configuration in smaller scale.

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.

Rotation of the vertical axis is accomodated using a CNC rotary table and ring bearing base.

Rotation of the vertical axis is accomodated using a CNC rotary table and ring bearing base.

 

Fixture mounting is the a second CNC rotary table with T-slots to attache adapter plates.

Fixture mounting is the a second CNC rotary table with T-slots to attache adapter plates.

The meter attachment post can accomodate any instrument the customer might want to use, from simple light meters for quick tests, to more involved spectroradiometric testing.

The meter attachment post can accomodate any instrument the customer might want to use, from simple light meters for quick tests, to more involved spectroradiometric testing.

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.

A laser alignment tool insures the fixture rotational center is aligned with the meter sensor

A laser alignment tool insures the fixture rotational center is aligned with the meter sensor

A laser line tool attachment alingns the fixture rail with the meter rail to assure squareness of the setup

A laser line tool attachment alingns the fixture rail with the meter rail to assure squareness of the setup

With the meter post/rail aligned and the fixture center aligned with the meter sensor, the rig is ready to mount and test the actual luminaire sample.

With the meter post/rail aligned and the fixture center aligned with the meter sensor, the rig is ready to mount and test the actual luminaire sample.

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.

Plants are becoming big fans of LED light, thriving on the delivery of the light they need, without the waste of white light they don’t even see.

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.

The leg stands can be adjusted to move the light source close for early growth stages.

The leg stands can be adjusted to move the light source close for early growth stages.

Living in the northern Midwest, we endure many months of pretty pathetic solar conditions. Short days and cloudy conditions do not support healthy plant growth, indoors or out. In our case, we grow small patches of grass for the cat all year round. The problem is, using the normal rye and oat sprouts, combined with the destruction of the cat puts on these little patches requires regular re-starting and re-growing the crop. This also applied to growing savory herbs for cooking, or starting fresh annual flower seeds for planting in beds or planters around the house all season. For all of these purposes, we’ve experimented with a small light that has been hanging from a shelf in the laundry room connected to a timer, generally getting in the way when it’s not in use, and falling apart over the 6 years its been working. Having the 3D printing and machining equipment around means we can make neat little gadgets at will, without hunting stores, to get exactly what we want in the end.

As the plant grows, the legs can be made longer to follow along.

As the plant grows, the legs can be made longer to follow along.

D12 is essentially the light engine from our experimental rig, tuned up and configured as a portable table light. This is sized specific to our needs, but could easily be scales up to other uses. It also uses some inexpensive Kingbrite RGB LEDs wired unconventionally, to deliver both Red/Green/Blue from 3 of the LEDs (Red being most dominant), and Blue from 2 additional LEDs. This is a combination I came to over time that delivered the greatest result. In the spectral comparisons, you can see the other combinations I tried using the same basic LED setup, changed only by the way the individual colors are wired. The power source is an off-shelf Meanwell 700mA driver. We connect this device to a wall mounted timer to cycle it on and off to suit whatever we are growing at the time.

These 4 color points were made using the same LEDs, changed through circuit wiring only.

These 4 color points were made using the same LEDs, changed through circuit wiring only. See the spectral power curves below for each of the numbered points shown.

Three LEDs are wired to split current between the Red, Green, and Blue, resulting in the Red being dominant. Two are wired for full current flow through the Blue die.

Three LEDs are wired to split current between the Red, Green, and Blue, resulting in the Red being dominant. Two are wired for full current flow through the Blue die.

I am no expert in this field. We came to the spectral distributions through basic research and simple experimentation. I am also aware that our red and blue color choices are not ideal, as those in the business will likely point out. If I were looking for the optimal solution, no compromises, the red would be a bit more red, and the blue a little closer to near UV. However, these colors are not found in inexpensive RGB LED packages, while the cost of blue and red LEDs in more ideal formulas cost many times that of those we used here. The question I had going in, was whether it was possible to achieve reasonably decent results without going off the techno-anal deep end. There is another advantage to using a light source of this type, and that is consistent and extended exposure hours. Daylight delivers and inconsistent 4-8 hours per day, with varying intensity. We used cycle times of consistent, high intensity, focused spectral power light, of 18 hours per 24 hour cycle, with just 6 hours of rest (when plants convert the food created to cell growth.) Using this approach, the performance of the package we put together to be very solid. First and foremost, the combination delivered growth when natural light supported nothing more than moldy potting soil. The time to grow samples from seed to transplant-able maturity, or usage (herbs or cat grass) were reduced to 1/3 that of any other daylight or indoor fluorescent based light source, including CFL grow lights, CFL daylight and full spectrum lamps, incandescent grow lights, and daylight. The LED grow light included in this little portable device blew them all away.

The following are the spectral distributions created and tested over the years as we experimented with various plant projects. Note that the PPFD values indicated are relative to one another (one direct reading taken from a single fixed distance), but do not reflect exact photometric values, as I have not completed a full photometric test of these for total output.

Config 1. This is the first configuration, resulting in a PPFD of just 21.6, but did fine for our first go around. PPFD is a measure of light output related to effect on photosynthesis, called Photosynthetic Photon Flux Density.

Config 1. This is the first configuration, resulting in a PPFD of just 21.6, but did fine for our first go around. PPFD is a measure of light output related to effect on photosynthesis, called Photosynthetic Photon Flux Density.

 

Configuration 2 delivered a PPFD of 85, and was significantly better than our first attempt. This came from adding green to the SPD, as well as increasing the driver current.

Configuration 2 delivered a PPFD of 85, and was significantly better than our first attempt. This came from adding green to the SPD, as well as increasing the driver current.

Configuration 3. This increased PPFD to 105. While there is a small amount of green still in the mix, I focused here on the Red and Blue. This produced the greatest result and is the configuration we now use regularly on most everything.

Configuration 3. This increased PPFD to 105. While there is a small amount of green still in the mix, I focused here on the Red and Blue. This produced the greatest result and is the configuration we now use regularly on most everything.

Config 4. This was an attempt to see how a red biased source would function. It didn't do as well, even though the PPFD 0f 93 would indicate it being second best. This is where plant-specific requirements might come into play more than raw metrics.

Config 4. This was an attempt to see how a red biased source would function. It didn’t do as well, even though the PPFD 0f 93 would indicate it being second best. This is where plant-specific requirements might come into play more than raw metrics.

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.

With the thawing of the midwest ice age, comes days on the bike once again.

With the thawing of the midwest ice age, comes days on the bike once again.

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.

This overview shows all of the solid-state updates that have been applied to the project. Note also that the rest of the bike has been heavily cut, stretched, slammed, etc....

This overview shows all of the solid-state updates that have been applied to the project. Note also that the rest of the bike has been heavily cut, re-made, modified, stretched, slammed, etc…. Not much remains of the original, although its original spirit remains visible.

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.)

The LED lamp kit, with its heat sink and fan is a clever solution and just fits in the headlight housing.

The LED lamp kit, with its heat sink and fan is a clever solution and just fits in the headlight housing.

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.

The headlamp incorporates LEDs for turn indicators as well, within the lamp itself.

The headlamp incorporates LEDs for turn indicators as well, within the lamp itself.

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 tail light and rear turn signals tuck in nicely with the rear of the bike as it now sits, looking like it was all supposed to be where it is.

The tail light and rear turn signals tuck in nicely with the rear of the bike – looking like it was all supposed to be where it is.

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.

LEDs are not the only thing I spend time fiddling with.  Torturing this bike is a nice release of creative frustration.

LEDs are not the only thing I spend time fiddling with. Torturing this bike is a nice release of creative frustration, and a place to practice with other tools, bleeding from knuckles, etc…

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….

Inspired by high speed photography

A conversation piece inspired by high speed photography

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.

Image out-take of the high speed photography caught by the Mythbusters

Image out-take of the high speed photography caught by the Mythbusters shows the spray of glass from the bullet entering the scope, which inspired me to attempt to create a static object that produced a similar visual impact, representing a successful result.

High speed video images of bullets blowing through fruit, and in this case a rifle scope, capture the impact and movement of an object weighing a few grams, traveling at 2000 feet per second, revealing the release of the energy this creates.

Now to the specifics. D9 is a conversation piece, meaning it is designed specifically to start or incite a conversation, even an argument. The visual effect I was attempting to capture was This particular image from an episode of the Mythbusters (History Channel property). They were testing whether the legend of Carlos Hathcock shooting a sniper through his scope in a legendary incident in Vietnam, was mechanically possible. In this, they placed several scopes some distance down range and shot rifle rounds through them to either deem it plausible or busted.

Conversation Note 1: The test was flawed in that it did not test period correct, North Vietnamese  optics. First, the optics of that day were not variable, thus were far simpler than the compound optics tested in the episode. I’ve dismantled several scopes over the years, and can confirm that the internals of modern scopes would be impossible to penetrate. In fact, the scope used in this design took a great deal of effort to “disassemble” with a steel rod and hammer, as the center section (area under the turrets) is very dense in compound lens segments of very small diameter. Fixed, simpler scopes do not include this denseness. Further, the tests did not represent the actual energy of impact accurately, as the distance of the shot was less than 50 yards, let alone 500.

The optics of a bullet passing through a scope are compelling, and invisible to us without high speed photography.

The optics of a bullet passing through a scope are compelling, and invisible to us without high speed photography.

Optics of Discussion. In thinking about this design, I was captured by the various “optics” involved. The optic of the angles and geometry involved in the shot, the optics of the and within the scope being shot. the optics of the shooters scope, the optical challenge of shooting through a tube that is 1″ in diameter, with a thin shell presenting an entry target of 1.5″, from a distance of 500 yards (a little more than a quarter mile), the optic imagery of the bullet passing through the glass, and the unavoidable optic of the repercussions of such an accomplishment. I was also captured by the reaction of the glass, and the release of energy in both the entry and exit directions (shown in tests by others) when the shot is made. Its all very intriguing, which is what makes it such a compelling story / legend.

Any deviation from a straight through shot would likely have resulted in less than a straight through result.

Any deviation from a straight through shot would likely have resulted in less than a straight through result.

Conversation Note 2: The scope Hatcock used was an 8 power Unertal and the distance the shot was taken from was 500 yards. The claim is that he saw a glint of light from his target, which he used as a point of aim. The optical field of view of an 8 power scope at 500 yards is around 75 feet. Thst  means he was able to recognize and place a target that was 1/600th the field of view, smaller than the width of the cross-hair wires inside the scope of the day. While not impossible, this is on the very extreme edge of it.

Conversation Note 3: The glint from the targets scope indicates the sun was behind Hathcock, and that his target was aiming at him directly into the sun. With a field of view of the same 75 feet, he was not only fighting the glare from the sun through optics with marginal clarity, he was seeing Hathcock in the shadows at the same 500 yards? This seems the most unlikely aspect of this story.

Conversation Note 4: At 500 yards, for the bullet to travel through the scope tube, the angle would have to be essentially perfectly in line with the scope axis, as any deviation from that angle would result in deflection defeating the the result. That means zero wind drift effect, and zero angle of inclination between the shooter and the target. This seems optically possible, and practically on the verge of impossible.

Conversation Note 5: The bullet would need to not only travel the distance of 500 yards but still have enough energy to drive through the scope itself. At that distance, a 175 grain 308  bullet would still be carrying an energy of 1167 ft. lbs of energy, about the same as a 22 LR bullet at point blank range. This seems enough energy to drive through the scope glass. Whether or not there would be enough energy or enough of the bullet itself intact after blasting through the glass is another story.  It is possible that the lower energy state is what kept the bullet from exploding when it struck the scope, which renders any tests done with higher energy states for verification totally invalid.

That all said, Hathcock was one of the best shooters of the time, decorated many times, and recognized for his contributions. Nothing here is intended to defame that. His credibility is what makes this whole story so intriguing, as he had no reason to fabricate such a story at all. I have seen some truly jaw dropping shots taken by marksman in my own 40+ years of shooting to know that there are people who know how to place shots with precision beyond human comprehension, high speed images or not. The shot is not impossible. The bullet, once loosed, was going to travel through a spot in space down range equal to its physical diameter of .308″. That could have, indeed, been within the diameter of the objective bell opening of a scope.

My goal was not to prove or disprove the legend. My goal was to create a static object that presented the visual, or optics, of the composite moments of the bullet traveling the last 24″, and the spray of glass that would have resulted in both directions. The glass spray was created by printing two structures on the SLA machine in transparent material, then coating those with clear urethane, which was then dusted with shattered glass. Internal to the scope are 2 LEDs aimed outward. The top turret cover is a dimmer knob, while the section of rifle below, printed on the FDA machine (sanded and painted) houses the driver and a military style on-off push-button switch to cap the whole design aesthetic.

 

 

Edit May1

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.