Now, after this introduction, let's have the first post.
A disclaimer: I'm a hobby sabersmith and a saber board designer. But I'm far away from being a skilled blade builder. I made my share of segmented LED strings and multiple neopixel based builds, and I'm happy with the results, but I'm fully aware - and quite happy about - that other are way better at it as I'm, so I can learn from them.
So here is my simple neopixel blade assembly guide to launch the topic:
- buy good quality neopixel stripes. I warn from cheap sites, especially some sources from AliExpress have dubious quality. My latest one I sourced from this site: http://www.ebay.de/itm/191956702454?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
. It is a German site, but what I wanted to share is that since my first neopixel posting price of the sripes drop fast, now for 40$ you can have 2m of the densest stripe, one year ago it easily hit the 100$ mark.
- try not to solder the stripes. I have some skills with soldering, but the stripes are not made for it. You can cut, not problemo, soldering it is a xxx! Nevertheless with some skill you will manage it. It a bigger problem that it will break the integrity of the strip, which might impact dual worthiness or generaly speaking robustness of the blade.
- buy the 144LED/m type, less dense stripes are great, but not for sabers. You need the dense stripe to avoid pixeling.
Now to some pictures I took from my latest blade assembly:
Most stripes come with connectors on both sides to be able to chain multiple segments together. This comes in handly, because instead of soldering directly on the stripes you can join the wires of the connectors. The - so far - most common design is to attach 2 stripes back to back, with the first pixel of both stripes at the bottom of the blade. Wiring is easy: connect GND to GND, 5V (supply) to 5V and DIN to DIN, as seen on the next pic (the stripes I ordered so far all had wire assignment as follows: white - GND, red - 5V (supply), green - DIN (serial input)
The basic unit of a stripe seems to be a 0.5m long pixel chain, which is attached to another with the same size, so all stripes are assembled using 0,5m segments. At the joint of the segments there are bigger landings for soldering (see next pic, in the middle), making the distance between two adjecent pixels greater than at other positions along the stripe. My first though was logically, that this distance will appear as an irregularity in the blade, therefore I started to desolder, cut, solder again. I s***d up and had to buy a new one, so I do not recommend doing so. In my newest build I did not touch it and I can conform: no irregularity is visible, this distance is still way too small to be recognized.
If you choose the back-to-back design, attaching the stripes is made confortable by the double sided, clear adhesive tape present on many of the commercially available stripes. I choose to attach them so that there is a pixel on a side between 2 pixels of the opposite side, i.e. interleaved. I figured that it migth give an even smoother illumination along the blade. The adhesive is insulating, therefore you do not have to worry about the small landings on the back of the stripe touching, but even if your stripe does not come with adhesive, or it happens to be non-insulating or bad quality, an interleaved configuration makes sure the landings do not overlap (you only have to be cautions at the soldered joins as mentioned above).
As you can see, assembling this basic design is not at all difficult, just make sure you align the stripes and press them well together before moving onto the next few inches.
A note on voltage drop and adding wires: I saw few people mention that their stripe seems to be more dark at the end. This can well be due to voltage drop. A logical solution - which led me to extensive soldering and frustration - is to add additional wires to lower the IR drop along the stripe. It can be done, migth help, but there is a drawback: if you but these wires between the sripes, there will be a gap. And you do not want that gap, because it will be visible as shadow in the blade. For achieving a good and uniform brightness along the blade, pressing the stripes together best as possible is crucial.
I will do some more pics on how I diffused the blade. I used basically the same technique I applied to segmented LED string blades:
- TCSS transwhite blade
- with the accompanying diffuser rod (!!!)
- and a packing foam wrapped around the stripes.
To the number of LEDs/pixels: a standard 32" blade needs around 120 pixels in a row (i.e. 240 if you use the back-to-back technique), that is why I geared LSOS to support that number or less.