This section goes into nitty gritty details about soldering NeoPixel strips, rings, and wire connections.
We'll show you how to splice and solder wires to connect up your microcontroller, and how to solder directly to the pads on the strip. We'll also cover connecting two strips end-to-end to lengthen them.
5V (red wire) and G (black wire) are the power pads. You can connect wires to any pixel in the strip on these two pads and the whole project will get power. Power flows both ways along the strip. This is handy to know! If you damage the pad you're soldering to (we've all done it, no worries mate) then you can just solder the 5V or G wires to a different pixel.
IN and OUT (white wires) are a bit less promiscuous. These are the data pins, and data must flow from the microcontroller to the IN pad. No exceptions -- the strip will simply not work otherwise. If you want to add another strip or ring onto your project, solder from OUT on the first strip to IN on the second.
If your strip has a fourth solder pad, it's likely that you've got a DotStar strip and this is the CLK pin. Treat it like a data pin -- solder from the IN end.