Imperial Journey

After an hour or so of playing with various settings and effects there was nothing left but admitting defeat. The LED strips on the bottom of the railing were great accent lights and terrible Christmas lights.

As I sat sulking in my chair, glaring at the lights, I recalled that I had an “extra” roll of pixels from the Mega Tree build. These were basically Christmas lights. Find where I hid the roll, plug it in to the end of the under-rail lights, and loosely wrap it around the railing to see how it looks. Fire it up and stand back.

And it looks great! This is what Christmas lights are supposed to look like! Hmm, three strings would cover the entire railing. Head to the computer and order two more strings.

With a full set of light strands in hand it was time to wrap them around the top rail. She Who Must Be Obeyed suggested “you know, it would look nice if they were draped from the (horizontal) wires”. Why yes, yes it would! And this makes it easy to adjust the length – just fiddle with it until everything was bowed the same amount.

Grab a handful of zip ties, fiddle with the spacing, and zip tie the lights in place. “Patiently” wait for nightfall and fire up the lights. Now This is Christmas!

Login to the WLED controller and start trying the 100+ effects that WLED provides. Find a half dozen that I like and save them into a playlist. Sit back and admire our now festive deck.

Not quite a “I meant to do that!” situation, but worked out in the end.

Tis the season again. Pick a (somewhat) “warm” day and get all of the Christmas decorations up. To my pleased surprise I found all of the pieces of the Mega Tree, put them together, and everything worked! How did that happen???

Night time rolled around and everything looked great. Then She Who Must Be Obeyed asked the question: “Can we add some Christmas lights to the deck railing?”

Why, yes! Yes we can!

I’ve been thinking about adding lights to the deck railing ever since we installed it. This provided the impetus to actually do something.

My vision was to add accent lighting to the bottom of the railing. You want to control the brightness, so dimming is a requirement. There isn’t much difference between white LEDs and full color LEDs, so might as well go with color changing LEDs.

Or, even better, based on my experience with the Mega Tree, go straight to computer controlled pixels. This let’s you do full Christmas effects! Clearly the only way to go.

This time use the full size LED strips which are much easier to work with than the ultra narrow strips from the Wizard Staff. The full size strips are available in outdoor versions which have a heavy silicone sheathe that protects them from the weather and from damage. And they have an adhesive backing, so just peel ‘n stick on the bottom of the railing.

Right. You know better than that…

I don’t trust adhesive to stand up over the long term for applications like this. They also make a U-shaped aluminum channel for mounting LED strips. These channels have a snap in plastic cover that locks into place over the LEDs making sure they don’t go anywhere. Even if the adhesive fails completely everything is still secure.

And the channels are white, so they will blend invisibly into the white railing.

These channels are commonly held in place with double sided tape. Or…. You can run screws through the bottom of the channel. But the railings are (heavy) steel – you can’t run screws into that.

But you can drill and tap holes for machine screws. And I have drill bits. And taps. And a box of 8-32 stainless steel machine screws.

Order the LED strips, aluminum channels, and the electrical cable to wire everything up.

Drill and tap the holes in the bottom of the railing. Since I am experienced and careful I was able to accomplish this with only one broken tap. Screw the channel into place. Hey, it does disappear!

Now to install the LED strips. Thes strips come in 16.5 foot (5 meter) lengths. The long side of the deck is 22 feet. And I need a right angle connection.

Unlike my experiences with the ultra narrow LED strips, these full size strips are easy to work with. Cut to length, solder wires to the pads, and cover the connections with hot glue to protect and insulate. Check the full length on the bench and everything works.

Take the 30 foot long LED strip to the deck, peel off the backing, and stick it inside the channel. Come back and pop in the plastic covers and Viola! Done!

Hook up the WLED controller and test it. Still working! And there was much rejoicing!

Wait for nightfall, fire it up, choose some different WLED patterns, and admire my handiwork.

It was boring. It worked perfectly, but had no impact. You couldn’t see the LEDs – they were inside the channel, behind a diffuser, and below waist level. The light was shining down on the deck providing the accent light I had originally envisioned. It was nice, but it just wasn’t Christmas.

Crud.

To be continued…

WLED can treat a string of LEDs like a TV and display complex images and animations. Basically it treats a string of LEDs like a two dimensional matrix.

It does this by arranging the LED string in a serpentine pattern. The LED string goes up, down, up, down until it fills the 2D array.

The intelligent LED strings I’m using can be cut apart and re-connected between any two pixels. The backing for the string has three copper pads that can be connected by soldering wires to them.

With standard 1/2″ wide LED strings this is (somewhat) easy to do. With the ultra thin 2.7mm high density strings it is a nightmare.

To make the display look right you have to have the same number of pixels in each row. The original plan as to cut eight strips the same length and solder them together.

I tried. Several times. Managing to destroy several lengths of LEDs. The worst part was actually getting the connections to work a couple of times – until you moved the strips and the solder joints failed. I didn’t have the skills, equipment, or dexterity to pull this off. At lest not with any trace of reliability.

The electrical engineer proposed just wrapping the LED string up and down without cutting or soldering anything. This “wastes” some pixels at the top and bottom where you reverse direction of the LED string, but it avoids the need to cut and solder.

The first time I tried this I bent the LED string too much and damaged it. I tried cutting out and repairing the damaged sections. It almost worked. I managed to get the whole string to light up a couple of times. But as soon as I touched anything the fragile solder joints failed. After about three hours I gave up and ordered another roll of LEDs.

With the new roll of LEDs in hand I very carefully ran the string up and down the ribs of the inner framework. At each end I used the largest bends I could and left as much slack as possible in the string.

Completely paranoid now I checked the LED string for proper operation as I installed each of the eight legs. This time the whole string worked.

Slip the controller into its pocket and connect it to the LED string. Plug the controller into an external power supply and turn it own. The LEDs sprang to life!

So far, so good. Fire up the laptop, connect to the WLED controller, and start trying different patterns. It works and looks great. And there was much rejoicing!

With the CAD work done and parts in hand the next step was to actually assemble the Orb. Of course the electrical engineer had some last minute changes. Batteries kept falling out of the battery box, so he selected a different one.

Good news: the new boxes were close enough in size that the fit on the mounting plate. Bad new: the new boxes had different mounting holes.

No problem! Grab the 3D solid models for the new battery boxes and add them to the CAD assembly. Delete the mounting holes for the old boxes, project the mounting holes for the new boxes, and hit print.

Mount the battery boxes and screw them into place. Slide the voltage regulator into its slot. Slip the controller into its pocket. Everything fits!

Now we just need to wire everything together.

But before that we need to install the LED strips.

With the controller in place the next question was how to power it. The electrical engineer determined that we would need four 16650 Lithium Ion cells and a voltage regulator to make this work. He identified the parts he wanted to use and sent me the part numbers.

The datasheet for the voltage regulator had a mechanical drawing with dimensions. OK, that gives me the information I need.

The batteries would go in two battery holders, each holding two cells. Tracking down the part number on the Internet I discovered one of the greatest advances of civilization in the last 20 years: dimensionally accurate downloadable 3D solid models of the parts! I knew that these existed, but this was the first time actually using them in anger.

Let me see… The battery holders needed to be mounted on a flat surface about “this” big. Play with geometry for a few minutes and I had a rectangle the needed size positioned between the Orb ribs. Extrude it about 0.080″ thick and I had a mounting plate for the battery holders fused into two of the ribs.

Position two of the battery holders on the mounting plate. Project the mounting holes from the battery holder model to the Orb inner structure model. It all fits and looks good.

Rotate the Orb around and add a mount for the voltage regulator to the back of the battery mounting plate. The voltage regulator is a tiny 1″ x 1″ circuit board with components sticking up. Design a slot for it to slide into with plenty of room on both sides for air flow – voltage regulators can produce a fair amount of heat.

Assuming the actual production parts fit the Orb should be ready to go!

As Halloween approached the electrical engineer freed up time to start working on the Wizard Staff again.

With all of the pieces for the dragon paw and orb done I assembled it to check everything out.

And discovered several things I didn’t like…

Remember when I said 5″ was the Goldilock Size? When put together it just didn’t quite have the presence I wanted. There were also several things about the design of the inner structure I didn’t like: the slots for the retainer tabs in the top of the sphere had to be printed with supports. These were difficult to remove and interfered with smooth turning of the top. The locking ring covered some of the LEDs, hurting appearance. It was harder than necessary to install the LED strings.

I’ve redesigned this thing enough times that starting over isn’t a big deal. Open up a new CAD file and go to work. Make the new 6″ model with all of the changes and lessons learned so far. Print it out and fit the pieces together.

I’ll admit to being concerned that it was too big. Not so! In fact it could be even bigger! But 6″ looked good, had the presence I was looking for, and was easy to handle.

As I was studying the model to look for further improvements a realization struck: Hey! It looks like there is now enough room inside the Orb for the controller! And the battery pack. And the other supporting pieces we might need.

Well, see if it fits: Grab the controller and stuff it inside the inner framework. A bit tight, but I started visualizing how a support structure could be built to hold it.

A vague thought tickled the back of my mind – weren’t there even smaller WLED controllers available? Why yes, yes there are! Order one and wait “patiently” for delivery.

Slip this smaller controller inside the inner framework and try it in various positions. Find a location I like. Dig out a set of calipers and a steel rule and start measuring the new controller. Fire up the CAD system and design a structure to hold the controller inside the Orb. Add a little bit of clearance so that the controller will actually fit inside the pocket.

Hit the print button and let it run over night. Slip the controller into the framework and slide it into its pocket – and it fits perfectly! There is plenty of room for the rest of the components, so harass the electrical engineer for a list of the actual parts he wants to use.

The first question is how big to make it. The only way to decide is to make different sizes and see. Fortunately this is easy: starting with the existing 4″ design simply scale it 125% to create a 5″ version and 150% to create a 6″ version then print it out.

I printed a full 5″ model and then the top half of the orb in 6″ to see what it would look like.

After handling all of them the original 4″ seemed a bit small, 6″ seemed a bit big, and 5″ was the Goldilocks size – just right.

With the size selected, time to design the new inner structure. This was largely a rehash of the last design with more LED strips.

While 3D printing is amazing it isn’t magic. A complex structure like this needs supports for overhangs, and this design has a lot of overhangs.

Fortunately the 3D printing software is able to generate these supports automatically. Several different types of supports are available – in this case I used tree supports. Unfortunately you have to remove the supports and clean up where they connected to the actual part. Still, a small price to pay for the power of 3D printing!

With the orb itself in reasonably good shape attention turned to the dragon paw. Hmm, what about a heavy bracelet? It would look like the dragon had been wearing a bracelet and had its arm cut off just below the bracelet. This could both look good and support the constraints of 3D printing. And we should be able to use the space inside the bracelet for something!

The best thing about this approach is that all I need to do is add a disk to the bottom of the dragon paw – the bracelet itself can be designed later and the dragon paw, bracelet, and staff body joined with screws.

At this point things got ugly. I don’t have the original 3D model for the dragon paw. All I have is the 3D printer file – an STL file containing over 180,000 triangles. Fusion can technically handle this, but it doesn’t like it. Operations that normally take a small fraction of a second take several minutes to complete.

Fortunately all I have to do is import the STL into Fusion, add a disk to the wrist of the paw, and then export it as a STEP file. With patience and a bit of luck this was finally done.

This finishes off the mechanical work for this stage. Now to bundle up all of the pieces, add the LED lighting strip and controller to the box, and send it off to my co-conspirator the Electrical Engineer to mount the LED strips and solder them together.

This is likely to be a bit of a nightmare – we are using ultra high density LED strips that are only 2.7mm wide. The mounting pads for soldering are tiny and some of them are difficult to get to. This is well beyond my skill level – hopefully it isn’t beyond his!

A bit of background on 3D printers: hundreds of different filaments are available in a wide range of colors and materials. The cheapest and most widely used is PLA, so I’ve been using white PLA for the prototyping. The plan is to make the actual orb out of more expensive transparent PETG material.

With a functional prototype of the orb done the question is whether or not we can achieve the desired lighting effects.

To do this we are going to print an orb top and bottom out of transparent PETG and then wrap the LED lighting strip around the inner structure. This will allow us to determine how the light looks, but will not let us use any actual patterns or effects. The final orb will have the LED strips carefully arranged so that LED patterns can be used – much like was done on the MegaTree for Christmas.

Assemble the orb and fit it into the dragon paw. So far, so good – everything fits together. The transparent PETG for the orb looks good.

Now to find out how it looks with lights. The major questions are whether or not it is bright enough, does it have an attractive appearance, and how it looks when changing the color and brightness of the individual LED pixels.

Success! The LEDs are bright enough. They look good – the inner structure of the 3D printed shell works well to diffuse the light and presents an attractive appearance.The transparent PETG material achieves the desire look with and without lights. The dynamic patterns generated by the WLED controller work well. Basically, we have the technology to build the Wizard Staff we first envisioned.

Since this is a prototype there are some issues. Ignore the light shining through the dragon paw – the final version will be printed with black filament and painted. I’ve got thoughts around a mottled dark green skin with red veins and dark yellow nails. I’m going to have to learn how to use an airbrush before this project is over.

While the lighting effect is good, you can see the bands from the four strings of lights. This would work, but we should try increasing the number of light strings in the final version.

While the current size of 4″ is good it wouldn’t hurt to make it bigger – perhaps 5″ or 6″.

We need to figure out how to connect the dragon paw to the rest of the staff – just sticking a pole in the hole in the dragon paw wouldn’t look very good.

With the success of this prototype and technology demonstrator it is time to start working on the next version. I have too much experience to call it the final version…