Looking from the back, the crate has the incoming data on the left bottom, exit top left. We also have one power barrel connector on each crate, as well on the bottom left.
The wiring is in a zig-zag pattern through the crate such that we reach the goal having the incoming/outgoing cables at the right place.
Here some schematic representation - Stars represent the bottle-necks, the arrows the wiring between them. You can retrace that in the picture below.
| outgoing. 4-position female connector.
+-|---------------------+
| * <- * <- * <- * <- * |
| ^ |
| * -> * * -> * * |
| ^ v ^ v ^ |
| * * * * * |
| ^ v ^ v ^ |
| * * * * * |
| ^ v ^ v ^ |
| * * -> * * -> * |
+-|---------------------+
|
| Incoming. 4 position male connector.
The LED power inputs are long loose cables on both ends of the strip that we combine and solder to a barrel-jack receptacle pig-tail, see image below. Make sure to thread the wires from the LED under the data wiring between the bottles.
As a preparation for soldering, the pigtail needs to be shortened by about 10cm (4 inches), the LED power cables roughly by 6cm (2.5 inches) to not have too much slack. When removing outer insulation from the pig-tail, make sure to not injure the insulation of the inner cables.
You don't have to unfold the whole LED strip or put it in the box to solder on the power pigtail. Just do the whole process directly on the bundle of LEDs, it saves a lot of time. The below images have the crate in the background for illustration purposes.
Uninsulate about 1 inch of the wires going to the LEDs and twist together the red and blue ones separately. Put a ~1 inch of heat-shrink tubing up each pair now, so that we don't forget that - move it up enough that it won't heat up while we solder.
Put about 1.5 inches of heat-shrink tubing wide enough to fit around the pigtail insulation now as well - we need that later to tie everything together.
Now, uninsulate as well the wires on the pigtail about 1 inch. Now make a Lineman splice with the corresponding wire-pair from the LEDs (colors: red with red, white (pigtail) with blue (LED)). Solder the splice (it giving the twisting, the whole length of the splice is now probably about 1/2 inch).
(If anything: remember the Lineman splice - it is a very useful skill!).
Move the heat-shrink that we have parked on the LED cables to each connection and shrink with quick movements with a lighter (or, if that is not at hand, with the hot-air gun).
| Splice before solder. | Heat Shrunk. | Heat Shrink overall. | Done. |
|---|---|---|---|
 |
 |
 |
 |
Let it cool so that it is hand-warm again. Then move the heat-shrink parked on the pigtail up so that it squeezes the other heat-shrunk connection together and on the other end covers the outer insulation of the pigtail. Shrink that. Now we have a sturdy connection.
(Use the heat shrink of which we have large rolls in the electronic area on the left side on the shelf).
The Pigtail should be cable-tied to the crate for now. Later on we might want a stress relief flap screwed to the wood ?
This is how it looks when it is all connected within the final display: the data connectors are chained from crate to crate. A separate spine with power is supplying 5V to each crate individually.
Due to the cabeling, this is also fault tolerant: if power gets disconnected on one crate, it will be powered, through GND/+5V line of the data cables, from the two adjacent crates above and below.
All data and power connectors run up on the left side, so it is very simple to stack crates without much thinking when moving the installation. The cable-ties to secure the crates are the reusable kind.
