Keeping with the “three groups” motif…three Fadecandy boards, three sets of power terminals…three identical wiring harnesses were built, each distributing power and data to 8 NeoPixel strips. Each block consists of:
- 1X USB cable
- 1X Fadecandy board
- 1X 2-row, 16-pin IDC header and plug
- 1X 16-conductor ribbon cable
- 8X JST female receptacle
- 8X 22 gauge wires for 5V
- 8X 22 gauge wires for GND
- 4X 18 gauge wires for 5V
- 4X 18 gauge wires for GND
- 1X 12 gauge wire for 5V
- 1X 12 gauge wire for GND
- 2X Power distribution bus bars (1 ea. for 5V and GND)
- Lots of heat-shrink tubing in various sizes (do not use electrical tape)
For each receptacle, add an extension to the 5V wire, 22 gauge or heavier. Make sure they’re all oriented the right way, with the key in the same position.
Use a robust inline splice for the connection: twist the wires around each other, solder and cover with heat-shrink.
Take the first two conductors of the ribbon cable and peel away a few inches. The first conductor — pin 1 — gets connected to the data line for strip 0. Slide the heat-shrink tube over the wire before making the inline splice.
The second conductor — pin 2 — then goes to that strip’s GND wire…but, like was previously done for the 5V wires, this wire also needs a 22 ga. extension. It’s a three-way inline splice.
Repeat these steps, peeling pairs of wires off the ribbon cable and connecting to each receptacle’s data & GND wires.
The eight 5V and GND wires all need to meet up with 12 gauge wire to the power supply…that’s 9 wires total, but the power distribution bus bars only accommodate 7 wires each (and don’t take well to doubling-up). So pairs of 5V and GND wires were joined with 18 gauge pigtails (which can handle two strips worth of current) using three-way splices.
Conceptually, it’s similar to this:
Here’s one of the wiring harnesses nearly complete. The 18 gauge power pigtails haven’t yet been added.
If you have a label-maker, it’s extremely helpful to add strip number “flags” to each JST cable! They need to connect to strips in a specific physical order.
With no strips attached and with the power supply switched off, each unit was wired in one at a time. Power up, confirm power supply is happy, power down and repeat with the next.