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Archive for December, 2011

John’s 2011 RGB Megatree

Posted by JEC on 5th December 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 »