The Color Mixing Christmas Light Project

Discretely Controllable DMX Driven RGB Pixels

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2013 Lights, First Clip

Posted by JEC on December 15th, 2013

More clips coming soon, but here’s one to start with.  This version is quite heavily compressed, but was uploaded in a hurry so that some out-of-town folks could take a look.

And some still photos from a different song:

IMG_7228 IMG_7221

IMG_7220

There was quite a bit more traffic this year than we’d seen before.  We learned a few days ago that the lights were featured in one of the 2 large newspapers in the area: Places in Utah to See Christmas Lights

…as well as a second ‘local activities’ site: 8 Local Must-See Christmas Lights

Crazy.

Posted in 2013 Project, Drive Gear, Photo / Video Clips, Pixels | 2 Comments »

2013 Sneak Peak

Posted by JEC on December 2nd, 2013

Much more coming soon. But this should be a really fun year.

 

 

Posted in 2013 Project, Pixels | 1 Comment »

Halloween 2013

Posted by JEC on November 2nd, 2013

Some simple uplights this year.  We made custom vinyl silhouettes on the windows and a trio of magical singing pumpkins.  Artistic credit goes to Vansters for Edward Scissorhands and Dave Lowe for the angry cat.  The other images I can’t find anyone to attribute.

It took an afternoon to convert the original .jpg files into crisp and clear vector art for scaling and cutting.

The vinyl cutter works with stock up to 30″ in width, which was very convenient.

Click any photo to enlarge.

IMG_6973 IMG_6974 IMG_6982 IMG_6988 IMG_6991 IMG_6992 IMG_6994 IMG_6995

 

At one point during the night, a girl age 7 or maybe 8 came up the walkway.  She saw the pumpkins singing ‘Ghostbusters’ and watched them in amazement.  Her expression reminded me of walking through Disneyland on a warm autumn day and seeing each of your childhood heroes lining the streets.

A few minutes later, as she picked some candy from our bowl, I remarked “These are magic pumpkins,  you know.”

“Really?”

“Yes.  Does your family have any pumpkins at home?”

“We do,” she smiled.

“Have you ever seen them sing like this?”

Deep wrinkles appeared on her forehead as she considered the question.  Finally, her shoulders drooped with sadness.  ”No, our pumpkins can’t sing.”

 

 

 

 

 

 

Posted in Photo / Video Clips, Uncategorized | 1 Comment »

Ragnar Wasatch Back Light Vests

Posted by JEC on June 24th, 2013

We, along with local gym Rage Fitness were asked to sponsor a relay team for the 2013 Ragnar Wasatch Back relay race.  Teams of 12, 6 or 3(!) take between 17 and 48 hours to run almost 200 miles through Utah’s mountain ranges.

Since 1/3 of the race takes place at night, the team wanted an easy way to identify their support vehicles and team members.  They asked us to come up with a neat LED display of some sort.

For the two cars (both of which had roof racks) the choice was fairly easy.  We installed strings of RGB pixels around the roof perimeter.  They were controlled by portable playback boxes and sealed lead-acid batteries.  We’d designed this portable system several years ago for a theme park on the east coast.  As the playback boxes moved through the park, an on-board GPS system would trigger various patterns and colors, depending on where the system was currently located.  It gave the park entertainment group a way to match the moving lights with local decorations, which was pretty neat.

In this case, we had a pair of the playback boxes left over, and they were perfectly suited for the job.  The lights ran a ~15 minute loop of different looks, and the batteries easily powered the system through the night.

The runners all loved having such and easy-to-find landmark amidst a sea of other vehicles and people.  Over 250 teams participated, each with 2 vans and 6-12 people.  Makes for some crowded mountain roads and parking lots.

IMG_6450

 

For the runners themselves, we needed a different approach.  The result had to be durable, fairly lightweight, resistant to the elements and cleanly executed.  And, we had about 36 hours to complete them.

Last year, we designed the pixel-mapped jogging jacket.

It was awesome.  However, it was form-fitted to a single person, and that wouldn’t be convenient for an overnight team to share.  So we started differently for the team vests.  Race rules said that each night runner had to wear a yellow reflective safety vest, so we purchased a handful of them from Lowes.

IMG_6443

 A somewhat flexible grid of lights seemed like a good idea.  So I grabbed some bits and pieces from the local craft store.

Plastic Yarn Grid

Plastic Yarn Grid

 

Fake Leather & Sheer Synthetic Fabric

Fake Leather & Sheer Synthetic Fabric

Clear Vinyl, Heavy Gauge

Clear Vinyl, Heavy Gauge

A 7 x 7 grid of smart pixels was attached:

IMG_6440

DMX Playback Card

DMX Playback Card

The circuit board was left over from a different project.  It was designed to record incoming DMX, save it to an SD card, then drive 7 x RGB ‘dumb’ strips (ie, add +12v, then ground the red, green or blue lines to build different color mixes).  It was easy enough to rewrite the firmware and bypass the FET output stages in order to drive the smart pixels.  Plus, using old stock saves $300 in overnight PCB charges.

IMG_6444Add velcro, diffusing layers and sew the whole pouch to the stock jacket.

Test Pattern

Test Pattern

The vests worked wonderfully well.  Tons of compliments from other runners. There was no chance that our team’s runners would pass the support vans in the middle of the night unnoticed.

Running Vest at Night

Running Vest at Night

Night w/ flash

Night w/ flash

 

The lights were crazy bright, even though I’d compressed their maximum intensity to just 68% of normal.  The attached LiPo battery packs were easy to recharge and contained more than enough power to get through the night.  44 frames per second of DMX playback made the patterns and transitions silky-smooth.

All in all, a great success.  The runners vow to return next year for another round.

If there’s any interest, I’ll track down some video clips of the vests in action later this week.

-John

Posted in Pixels | 2 Comments »

2012 Video Clip

Posted by JEC on December 25th, 2012

Merry Christmas! There’s a new video clip at the bottom of this post.  It’s uploaded in HD, so you should be able to click on the YouTube screen and enlarge it if you’d like.

And, hooray for fresh snow!  You’ll see that a bunch of the tree bulbs are glowing under the snow.  Makes for a neat effect.

 In an earlier article, I’ve described some of the backstage technical details which make everything tick.

Late last night, a friend of mine (a very experienced lighting designer & master GrandMA programmer as well) came to visit.  He loved the different looks, and especially the fact that nearly all of them could stand on their own, background music or not.   We talked for a while about the behind the scenes gear that make everything run so nicely.

He asked what the ‘next step’ might be.

I had to think.  There’s currently available several RGB mappable, flexible pixel mesh products in the professional market.  And as they say, you can have anything in this world for money.

But – and this is perhaps more important – this is a home in a nice quiet neighborhood.  It’s neither a rock concert nor a rave.  And to this point, it still looks like classic Christmas lights, albeit slightly enhanced.  I think that’s important and magical.

At least for now, that’s how it’s going to stay.

A few nights ago, I went out to get the mail and noticed a car parked across the street.  They had their window open, and through it I could hear John Denver & the Muppets singing ‘Silent Night’ (see comments below).  The car was packed with 8 year old boys and their parents.  I asked the boys if they wanted to stand inside the tree and watch the patterns from there.

Super excited, they tumbled out of the car and over to the yard.  As I parted the light strings so they could climb in, one of the parents remarked that their friend said they ‘had to come visit the diamond house before Christmas.’

“The what?” I asked.

“The diamond house.  Because it’s so sparkly and amazing.”  That made me smile.

Thanks for visiting!  Enjoy the video and stills below.

John

(If the YouTube player isn’t displayed below, the direct link is http://www.youtube.com/watch?v=3pulVKhPms0 )

Click any still picture to enlarge.

Posted in 2012 Project, Photo / Video Clips | 8 Comments »

Christmas 2012

Posted by JEC on December 7th, 2012

Cinderella’s Castle

In the fall of 2011, we were lucky enough to visit Walt Disney World in Orlando.  We spent the day and evening there, and were gathered around Cinderella’s castle for the evening lighting ceremony.  It was a magical moment, and the shaky cell phone photo taken above became the inspiration for our decorations this year.

(All photos in this post may be enlarged with a single click.)

Cool Lights w/ Green.

2012 House + Lights. 

Green + Warm Walls

 

Our goal this time was to create something beautiful, classy and memorable.  We wanted still images which could stand on their own, plus  sequences which could gracefully flow and be complemented by music.

I think we succeeded in grand style.

A couple of still photos are included above, and the boring technical details below.  I’ll post some video and more stills in a week or two.

Overview

  • The stone face of the house is covered with warm and cool white LED panels.  We lost track of the exact number installed.  The CAD guy in our builder’s office claims that there’s about 944 square feet of stone which need to be covered.  Each panel of lights measures 2 meters x 1 meter.  Total LED count here is somewhere in the 22,000 – 24,000 range.
  • 240 watts of LED floodlight.
  • ~4,100 discretely controlled RGB bulbs on the 25′ tree.
  • ~150 ‘sparkle’ lights (higher power, 3 x RGB emitters in a single package), also on the façade.
  • More RGB bulbs on the rooflines.  Maybe 250 – 300?
  • 28 (?) universes of DMX over ethernet, totaling ~ 5 megabits per second of data throughput.
  • Custom designed DC dimmers and Art-Net–> DMX bridge interfaces.
  • Lighting computer jam syncs to time code generated by audio computer, which keeps things nicely locked together.
  • Small radio transmitter broadcasting in stereo on 87.7 MHz.

Mounting

A huge challenge was figuring out how to attach the lights to the house’s stone walls.  It’s done in ‘dry stack’ style, which means that most of the stone sections stick out 1/2″ to 3/4″  in front of the mortar.  So there’s lots of area to grab on to, but the shapes are very irregular, with often non-parallel sides.

I considered C clamps (too much money, didn’t want scratched rock) and plastic alligator work clamps (didn’t open wide enough, except for the super expensive ones).  At 200-300 pieces required, cost starts to increase in a hurry.

Plastic Conduit – 2.5″ and 3″ sections

While trolling through Lowes I found a perfect solution.  Plastic gray PVC electrical conduit is available in many diameters.  I bought 10′ sections of 3″ and 2.5″ pipe to test.  Using a chop saw, I cut a section of pipe in narrow bracelet-sized pieces, with widths varying between 3/16″ and 1/4″.  Then, I used the same saw, I cut about 50 degrees out from each circle, leaving me with a section of plastic which looked a bit like PacMan.

These sections were both very flexible and very strong.  They easily stretch to the width of a stone section, but also grab tightly when released.

Pipe Clamp Grabbing the Rock

For $40 in pipe (and a lot of annoying plastic powder kerf), I’m absolutely thrilled with the results.

Electronics

I designed a daughtercard which, through a short section of ribbon cable, mates with Parallax’s Spinneret ethernet module.  And thus, a two universe Art-Net to DMX bridge was born.  Parts cost for the daughtercard was just a few dollars.  It works beautifully, running at an easy 44 frames per second on both outputs.  If I get some time in January, and if there’s any interest, I’ll release the .spin code I used..  Size of the card is only about 1″ x 3″, which is nice and compact.

In this case, the panel lights use one universe and the floodlights are on the other.

Art-Net Bridge Card for Parallax Ethernet Module

Art-Net bridge module, mates with Parallax’s ethernet / Propeller development board, the Spinneret. Includes 2 x XLR5 output jacks and proper RS485 drive stages.


2 universe Art-Net bridge. Not shown is the ribbon cable which connects the two.

The house face lights use 120 channels of  one universe and the flood lights 12 of another.  Crazy that it’s easier – at least in this case – to add a universe than to run more cable between here and there.

The stone face lights are controlled by five DC DMX dimmers I designed.  Each drives 24 discrete outputs or 12 warm/cool pairs.  Everything except the 24v/2.5A power supply fits on a 3″ x 5″ PCB card, which is nice and compact.  The drive stages are rated at 2A each, but the panels only draw about 80 mA each.  That leaves plenty of headroom, and no noticeable heat is generated anywhere on the card.  Connectors on the left are for Neutrik’s Ethercon series.

Earlier this summer I previewed some different styles of net light.  I was concerned because all of the AC-driven ones flickered annoyingly when I glanced my eyes back and forth across them.  The flicker was at either 60 or 120 Hz, and it bothered me.  It’d be easier, I reasoned, to go with custom panels which could be directly DC powered.

So I asked the factory to modify an existing design for +24v DC operation, which they did nicely.  The dimming engine runs at a 5 KHz refresh cycle, which means the light output is both camera- and eyeball friendly.


Power Draw: 4 LED wash lights + 24 channels of house panel light.


Power Draw – 4,080 RGB nodes on tree

 

Total data rate is ~ 5 megabits per second sustained.

Questions?  Comments?  It’s truly beautiful to see at night.

-John


 

 

Posted in 2012 Project, Drive Gear, Photo / Video Clips, Pixels | 4 Comments »

Halloween 2012

Posted by JEC on October 25th, 2012

 

Click to Enlarge – 2012 Ghost Tree

  • 150 meters of white EL wire, broken down to 30 strings @ 5 meters each
  • One extension cord
  • One mechanical on/off timer for the tree.
  • Built-in dawn / dusk sensors for the house light circuits.
  • Zero sequences
  • Zero dimmers
  • Zero channels
  • Zero universes
  • Zero patching
  • Zero stress
  • Images captured at 1.6 seconds, f/2.8, which is underexposed by .7 stops

Close up – click to enlarge

 

Click to Enlarge

Posted in 2012 Project, Photo / Video Clips | No Comments »

Pixel Mapping a Jogging Jacket

Posted by JEC on September 24th, 2012

Blue and White Stripes

Because why not?

A few weeks ago one of my wife’s friends invited her to run an In-the-Dark-5K race, the proceeds of which benefit the Olive Osmond Hearing Fund.  The late Olive was the mother of the famous singing Osmonds, and the grandmother of several of our friends in high school.

The race website said

We encourage everyone to wear their brightest colored running gear!  Don’t forget your glow sticks and body paint! We will have black lights on the course to be sure that everyone will GLOW for HEARING!

Plus, other friends from long ago live in the same city (Logan, Utah).  So we decided to take a road trip.

Back when she first heard about the race, I’d just taken delivery of 150 meters of white EL wire, which will be used in a Halloween project next month.  I was testing the EL inverter in the workshop when she walked in.  I suggested – half in jest – that we wrap her jacket in glowing wire for the run.

“But can it change color?”

“Well, not really,” I said sadly, recalling that that with a bit of electronic sorcery the phosphorescent hue can be shifted a bit to the left or right.  And with some even more clever math, it can be dimmed.   But that’s about it.

“No thanks then.  Maybe we could use some of your extra lights from the yard tree instead?”

This seemed like a lovely idea.  We sketched out some rough plans.  Later that afternoon, she took a trip to a nearby outdoor equipment retailer and returned with great handfuls of flat black webbing, plus an assortment of plastic clips, latches and turnarounds.

The drawings and loose parts sat neatly on the shelf until yesterday, the day before the race.

Construction

We designed a form fitting vest / jacket skeleton using the webbing, white marking pens and a stapler.  Once all the pieces were in the right place, the staples were replaced with machine stitching.

Color Changing LED Running Vest

LED Running Vest

She also fabricated a small pouch to hold the controller and battery pack, and attached it to the vest’s rear, just below the shoulder blades.

Pouch for Battery Pack

Close Up – LED Mounting with Zip Ties

The controller board was a a saved prototype from a different project.  It was originally designed to drive 6 sections of RGB LED tape (18 channels total, 2A peak per channel, that’s a lot of LED tape) using either live DMX or data stored on an SD card.  However, it was easy enough to repurpose a pair of pins to drive the LED node string.

Controller and DC-DC Power Supply

 

Controller and PSU Inside Protective Pouch

 

Battery Pack – LED Vest

Plus, it was free.  Because as any accountant will attest, massive sunk costs can be completely ignored a few months later.

The card contains a DMX input stage, plus a few pushbuttons and LEDs for user feedback.  I wrote a tiny program which captured incoming DMX at 44 frames per second,  then saved the data to an SD card.

An interesting quirk of memory cards is that although they can be read from very quickly and consistently, the write process is not always as smooth.  Even when writing entire sectors (512 bytes at a time) to the card, there can be random and variable delays incurred by the card’s internal electronics.  300 mS isn’t at all uncommon.

So the DMX capture code actually copies data to a very large circular buffer (at very precise intervals), and the SD write routine is triggered each time new data is ready.  Since the input buffer is big enough, the two routines never step on each other’s toes.  The result is perfectly stable recording and playback, even though both processes are running at different – and sometimes variable – speeds.

It’s an elegant bit of code, if only in a ‘you really had to be there’ sort of way.

Also extremely vital, because dropped frames are ugly and visually jarring.

An  8-AA, 2400 mA-H, NiMH battery pack supplies power.  Its output feeds a cute little 7-16v input, 5V/2A DC-DC converter, which then powers the controller and LED string.  Testing showed that the 42 LEDs pulled between 800 – 1500 mA depending on their state.  The battery pack was tested for an hour under load, with no problems.  The DC-DC converter didn’t become appreciably warm, which was nice.

Using a copy of Madrix Professional (again, sunk costs), I built a rough facsimile of the jacket’s LED layout.

Patch – 42 RGB Nodes on a Running Jacket

 

The rest was easy.  I arranged a cuelist of about 30 different looks, then let them cycle through over about 14 minutes total.  Madrix output DMX through an ENTTEC USB Pro interface, and the jacket controller, in DMX capture mode, recorded each and every packet.  In regular playback mode, the file is read and (if needed) looped.

Results

 

RGB Running Vest Plus Large Blacklight Fixtures


“Are you wearing a bomb?” asked a curious onlooker before the race started, and while the vest was turned off.

(How do you answer that question, anyway?)

This comment piqued the interest of a nearby campus police officer.  After we turned on the lights, he wasn’t as concerned.

2+ hour run time on a single battery pack

Not nearly as uncomfortable to wear as we expected it might be.

My wife, recovering from a shoulder injury, made good time through the run.

Overkill?  Certainly.  But it was fun to see people watch and smile.

Here’s some video from the race, then a few minutes inside which show some of the different patterns displayed.

Posted in 2012 Project, Classic Pixels, Drive Gear, Photo / Video Clips, Pixels, Point Source Pixels | 3 Comments »

John on Snowflakes

Posted by JEC on June 11th, 2012

The neighbors let us know, without mincing many words, that there will be Trouble if we don’t set the up the giant yard tree for Christmas again this year.  We’ve been told that kids living on the opposite corner of the development would howl in protest if they weren’t driven home – the long way – via our little corner.

Fortunately, last year’s anchoring system proved so strong and sturdy that I plan to extend the tree to its full 25′ height.  This means that there won’t be any extra node string ends on the ground this year, and the entire tree will be about 6′ taller.

But it’d be boring not to add something new to the collection.

For a few years, we’ve wanted to decorate the house with snowflakes of varying size and shape. Sadly, the daydreams have so far not materialized.  Certainly there are a wide variety of pre-fab wireframe snowflakes available for sale.  But I wasn’t terribly interested in the overall look.

A few years back, when we first started working with RGB LEDs overmolded on a cable, I drew up some simple snowflakes in the CAD program, then sent them to the shop which does all the metal forming for the products we sell during the day.  A 48″ x 96″ sheet of .06″ aluminum, fully tessellated with snowflakes, cost about $400 for materials and laser time.  This, by the way, was the after-hours cash price, so who knows the actual street price of the silly things. In this business, it’s often best not too ask.

(Note that all pictures below can be enlarged to full size by clicking on them twice.)

Laser-Cut Aluminum Snowflake, 12"

24" Aluminum Snowflake, partially loaded

Advantages: Discrete RGB is cool, but there’s already almost 4000 nodes on the big tree.

Disadvantages: The LED package is nontrivially large.  Wiring harness is bulky and adds about 3″ of depth to each snowflake.  The wiring spaghetti backstage is ugly.  Installing those nodes in aluminum holes is absolute murder on the fingers. For covering the whole house in snowflakes, the installation must be immaculate.

Plus, I didn’t just want bits of light arranged in a pattern.  I wanted a look which was seamless, fluid and beautiful.  So for 2012, the design constraints are

  • No nasty wiring harnesses
  • Low profile
  • Continuous color / shape
  • Ability to appear nearly invisible during the day
  • (Optional) color changing capability
  • (Optional) relatively decent pricing, as quantity will approach 60-100 pieces in varying size.

So without further ado, here’s a summary of thoughts, experiments and misfires which have percolated through over the past few months.

Hypothesis #1 – Backlit Plastic

During a quick trip to Lowes I procured a series of translucent plastic sheets.  One set, designed for use in commercial fluorescent lighting fixtures, was embossed with an interesting honeycomb pattern.  This plastic can be cut by hand or by machine, so it’s possible to make any desired shape.  Placing some RGB lighting tape leftover from the 2011 Superbowl project made an interesting effect.  However, where the LEDs touched the plastic, their shape and spacing was clearly visible.  Moving them farther and farther behind lowered the intensity but diffused the hot spots.  3-4″ seemed a good distance to work with.  But making 100 fairly low-cost light boxes to ensure good diffusion just didn’t seem fun.  Nor did mounting them on the side of the house.  The winter winds here can take your breath away, so safety is always a concern.

Hypothesis #2 – Sideglow Fiber Optic Cable

Sideglow Fiber Optic Cable

 

This is a pretty neat product.  While normal fiber optic cable is designed to transfer light from one end to the other with minimal losses, sideglow cable contains added magic which slightly disperses the light along its length.  The resulting product can be used as a replacement for neon tubes, but in a much more flexible way.  Traditionally, it’s driven by a 200 watt metal halide light bulb and a wheel containing dichroic glass filters.

Perhaps, I thought, the cable could be molded in the outline of a snowflake.  This moves the effect away from ‘light blobs in a row’, which is important for this project.

Some folks stateside sell the stuff at what seems to be very inflated prices.  Decent eBay sellers seemed to be from Asia, so I cruised Alibaba for a few hours in hopes of skipping the various middlemen.

The cable comes in varying thicknesses from 1-10 mm.  I brought in samples of several sizes, plus an 18 watt (2 outputs, each with a 3W RGB LED) drive source.

The verdict?  Nice but expensive.  Price ex Asia for 6mm cable (the smallest which seemed to emit enough light to be useful) is $1 / foot plus freight.  Any drive source less than 3W each of R, G and B is inadequate.  6mm cable has a bend radius of not less than about 40 mm.  So fine detail is out.  Driving high-brightness LEDs isn’t a big deal, but a properly packaged constant-current DMX-driven LED driver at 3 channels, even not counting our design time, would be ~ $30 each.

Thus making the house snowflakes a $5-6k project. Strike 2.

The driver would be relatively bulky as well.  So that’s strike 3.

Also note that the photo above is terribly, terribly overexposed.  That much brightness out the side of the cable doesn’t happen in the real world.

Hypothesis #3 – EL Panels

EL Paper Samples

 

The next step in the quest for something low profile and evenly illuminated led to EL wire and paper. Electroluminescent wire has been around for quite a while, and made especially popular as part of dancers’ costumes, shown briefly between commercials on television talent shows.  It’s fairly inexpensive, flexible and continuous in intensity.  However, it doesn’t dim well, it’s only available in single static colors.

The existence of EL wire, however, leads the curious researcher to something called EL paper.  It’s half a millimeter thick and can be cut to any shape with regular scissors.  Drive voltage is 100+v, with current dependent on the paper’s area.  It can be dimmed, but not easily. Still, this could be a neat, neat effect.  Continuous light output in an arbitrary pattern.

I found a few factories who could make panels 2 meters wide x 1 meter tall.  Sadly, the best pricing I could find, even when buying in largeish quantities directly from the maker, hovered around $0.023 per square centimeter.  Add designing a DMX-driven high voltage outputter (cough, cough… these don’t seem to even exist!)  for each snowflake and the project becomes ferociously impractical.  Plus, still single color per panel.

Hypothesis #4 – Edge Lit Acrylic

Here’s where things become very interesting.  Folks in the sign-cutting industry have, for a long time, made some striking art by edge-lighting pieces of plastic.  Further, designs can be etched in to the plastic, either using a stencil and sandblast method, a CNC router or laser ablation.  Each section of the plastic disturbed in some way catches light.

I bought from the local plastic shop four pieces of 3/8″ cast acrylic plate.  3/8″ is expensive, but it’s also the same thickness as my RGB LED tape.  These were precut in squares, one each of 6″, 12″, 18″ and 24″.  Retail price for the plastic was $70.

These guys have a nice little Epilog laser for cutting and etching, but its table size was too small to handle the 18″ and 24″ pieces.  I was referred instead to a shop which owned a drop-dead-gorgeous 150w Kern Laser, featuring a cutting area of 50″ x 50″.  Plenty of size and power for this project.

I emailed over some vector graphics files and we were in business.

4 Laser-Ablated Snowflakes.

3/8" Thick Cast Acrylic, Side View

300W 6 Channel DC Dimmer

We happened to have some extra high-power DMX dimmers in the shop – prototypes from a custom design built for a touring concert group.  These six-channel dimmers have a super heavy duty output stage, and digitally dims at a frequency far higher than the broadcast video cameras they were using.  Each of the two RGB banks can handle 10 meters of double-density (60 LEDs per meter) RGB LED tape.  For just fooling around, this is massive headroom.

I wrapped two snowflakes in LED tape and turned on the dimmer.  The results were spectacular.  Smooth, even illumination everywhere the snowflake pattern was ablated, and complete transparency otherwise.  The etched patterns are nearly invisible, even in daylight.  The prototypes have a very thin profile and are exceedingly simple to drive.  Each snowflake, even at full brightness, requires maybe 300 mA per color at 12v.  Over the next month or so, I’ll gin up a dozen or so 36-channel (12 x RGB bank) dimmers with an Art-Net front end.  Each snowflake will connect to the dimmer using a length of thin and inconspicuous CAt5 cable.  These will mesh nicely with the Art-Net infrastructure already in place.

As an interesting side note, it’s actually less expensive, component-wise, to design using ethernet than to include a properly optically and galvanically isolated input stage for DMX.

Underexposed by 2 stops to keep the color saturated. Amazingly crisp and bright in real life.

Zoomed Out

 

12" Acrylic Snowflake

There’s only one downside at this point: retail price for the laser time was $225.  Even divided by four snowflakes, it’s way too much money.  But the look is stunning and perfect, so we’ll figure out a less expensive way to proceed.  Perhaps even the vinyl stencil + sandblasting method will prove affordable at this scale.  I need to investigate whether a CNC router can produce roughly the same effect but at a fraction of the cost.  It may be a good excuse to buy a smaller (36″ x 36″) router just to have.  Or a biggish laser table.

Hah!

Anyway, stay tuned for fall.  The flock of snowflakes should be spectacularly beautiful.

If anyone has suggestions for pulling off this look without totally breaking the bank, I’d love to hear from you in the comments below.

Posted in 2012 Project, Drive Gear, Photo / Video Clips | 8 Comments »

John’s 2011 RGB Megatree

Posted by JEC on December 5th, 2011

 

Click to Enlarge

While last year’s triangle tree worked out fairly well, it was definitely a last-minute design.  12 feet tall and containing 16 x 42 node strings, it was fun to watch for the last couple weeks in December.

But there’s always room for improvement.

This time, we decided to start earlier in the year, in order to end up with something extra special.

During October’s indoor tree demo, we confirmed that 48 full strings of light added about 100 pounds of weight.  At that trim height, the wiring represents a substantial load & leverage force.  So based on Walter & Jackie Monkhouse’s detailed plans I build a rebar-reinforced concrete base weighing 120 pounds.  This was fitted with sturdy eyebolts as designed, then securely  anchored in the ground with a quartet of 3/4″ concrete stakes 36″ long.

On top of the base I added a two-part pole assembly based on 10′ sections of 2″ and 1.5″ rigid EMT conduit.  From the friendly folks at christmaslightshow.com I procured a 24″ star frame, a megatree hook set and a pully head.  From Lowes I bought, then installed, a geared winch on the pole.  This way the main tree assembly could move up and down for repairs, testing and potential bad weather.

Then, because of the recent 102 mph windstorm not far from our home, I added three external guy wires made of 3/16″ wire rope (rated at 800 pounds minimum breaking strength).  These attached to the top of the 2″ pipe, then anchored in the ground with more 36″ stakes, heavy turnbuckles and a handful of shackles.

The entire post assembly (20′ of pipe, less 2′ of overlap, plus about 2.5′ of star) was assembled on the ground, then tilted into place and anchored securely.

Using a 10′ A-frame ladder, I attached three StellaGreen strings to each of the hook head’s 16 angle brackets.  At this time, the pully head was resting at the top of the 2″ pipe section.  Had I used 1.5″ and 1.0″ pipe for the entire assembly, the hook head would have moved freely to the ground.  However, the sturdiness of the thicker pipe is reassurring.

Once the foundation was set and stable, the hook head was cranked up to full working height.

Finally, I built a base ring from 60′ of 1/2″ PCV pipe, joined together with simple sleeve fittings.  The string spacing at the base of the tree is about 15″ on center, and it’s a nice balance.  Our StellaGreen strings contain 85 RGB nodes on 10 cm (3.93700787 inch) spacing, plus an 2.5 meter pigtail at the beginning for convenient connection to a controller.  Thus, the strings offer more or less 28′ of light to work with.  In this installation, I didn’t want our home or the neighbor’s home to be damaged if the tree somehow tipped over.  So the tree is a bit shorter than it could be, per Mr. Pythagoras and some catenary sagging.  There’s about 3′ of node string at the base of the tree, arranged in a neat inverted sunburst pattern.

The tree is driven by a trio of E16-II Ethernet controllers.  Total power draw is around 800 watts peak.  85 nodes per string x 3 channels per node x 48 strings equals 4,080 nodes and 12,240 total control channels.  With a 44 Hz refresh rate across the entire system, color fades are as smooth as silk.

Neighbors say that at night, when they enter the neighborhood from 1/4 mile away, the top section of the tree peeks through the other houses like an iridescent spaceship.

 

Hoping to post some video clips in a day or so.  Click any of these photos above to enlarge.

John

Posted in 2011 Project, Drive Gear, Photo / Video Clips, Pixels | 9 Comments »