If you’re working on a solderless breadboard or aren’t using a Feather form-factor microcontroller, the Adafruit NeoPXL8 Friend provides similar utility to the NeoPXL8 FeatherWing but in a non-FeatherWing package.
The NeoPXL8 Friend breakout board provides logic level shifting from 3V devices to as many as eight NeoPixel strips, which can be connected one of two ways:
The 8x2 row header (16 pins total) provides a “Fadecandy-style” connection.
Fadecandy is a USB NeoPixel controller popular in large-scale LED installations. The 8x2 connector is fairly compact and low-profile. Assembled this way, the NeoPXL8 Friend could, with suitable Arduino code, function as a swap-in replacement in an existing Fadecandy project, or could make use of NeoPixels already wired for such.
The two RJ45 connectors provide an “OctoWS2011-style” connection.
OctoWS2811 is a similar hardware-and-software combo for large NeoPixel setups using the PJRC Teensy 3.2 microcontroller. These connections are bulkier but latch into place and ensure a specific polarity. Assembled this way, the NeoPXL8 Friend could, with suitable Arduino code, function as a swap-in replacement in an existing OctoWS2811 project, or could make use of NeoPixels already wired for such.
In either case, the NeoPixel headers mount on the FLAT SIDE of the NeoPXL8 Friend — the side with NO COMPONENTS — and are soldered on the component side. The breadboarding pins are done the OPPOSITE way — install from the component side, solder on the flat side.
Additionally, you still need to build a wiring harness between these connectors and your NeoPixel LEDs. The above is just a starting point.
Adopting these two wiring schemes mean that any existing tutorials for wiring up Fadecandy or OctoWS2811 projects are applicable to NeoPXL8 as well — it’s not starting over with a third incompatible standard.
This tutorial shows some Fadecandy-style wiring harnesses being made, using a ribbon cable and 8x2 IDC header, plus lots of soldering and heat-shrink. A multimeter with continuity beep is helpful in keeping track of data wires and grounds!
The OctoWS2811 product page on the PJRC web site shows RJ45 wiring harnesses being made by cutting open Ethernet cables.
You will also need to safely distribute 5 Volt power to all of your NeoPixels. This is not done through the NeoPXL8 board — it needs to be part of your wiring harness. This tutorial explains some of the issues in powering large-scale NeoPixel installations.
A third option is to install header pins on the NeoPixel outputs, so both the “ins” and “outs” are breadboardable…this may be useful for certain prototyping tasks.
There isn’t clearance for the outputs on a regular-size breadboard, but linking two breadboards side-by-side is often done with wider devices like this.
Unlike the FeatherWing, the NeoPXL8 Friend has space for both an 8x2 row header and two RJ45 connectors at the same time.
HOWEVER, if using the 8x2 connector, depending how one’s ribbon cable is crimped and strain-relieved, the RJ45 connectors may still be in the way…so you may want to leave those two connectors off unless you’re certain to need them.
Because we’re using hardware tricks, NeoPXL8 output works only on specific microcontroller pins. The Arduino library examples explain in more detail. On boards like the Adafruit Metro Express or Arduino Zero, it’s conveniently on digital pins 0 through 7, so you can use an 8-pin ribbon cable to link directly to the NeoPXL8 Friend’s 8 inputs. In other situations, the pins may be strewn in different places around the board.
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