For posterity, let’s take a look at the wiring schematic from the OOZE MASTER 3000 guide (you did at least skim that, yes?), to make better sense of the changes mentioned here…

Seven NeoPixel strips provide our icicles and drips, while a distinct eighth strand of separate NeoPixels makes the “drippings” at the bottom. It’s all powered from the Feather board’s USB port.

The concept is exactly the same as the prior project, just some of the parts are changed…


With an architectural-scale project like this, we can use regular-width, 60-pixels-per-meter NeoPixel flex strip. Fortunately this is the most common variety around!

I started with a full 4 meter reel, then divided into 8 half-meter strips. 7 for the icicles, 1 as a replacement spare. I already had some bits of NeoPixel strip from prior projects to cut up for the “splat” pixels, otherwise you might have to use that 8th half-meter for that instead, or some NeoPixel Mini Button PCBs.

The drip illusion seems most convincing if the strips are in the vicinity of half the window height. I tested on two windows…one a little shorter than a meter, one a bit taller…in either case, the half-meter strips looked great, so don’t stress over getting this just right.

Higher-pixel-density strips are available and will work, but please read the notes later about power requirements.

Driving the Pixels

The hardware driving this is identical to the OOZE MASTER 3000 project…which in turn refers back to the NeoPXL8 guide for tips about compatibility. A number of Feather boards — M0, M4, RP2040 and ESP32-S3 boards — will work in conjunction with a NeoPXL8 FeatherWing, and a few non-Feathers can work with the NeoPXL8 Friend (breakout) rather than the FeatherWing. Other microcontrollers like AVR or “classic” ESP will not work. The guide example code accompanying the NeoPXL8 library has comments regarding compatible hardware.

I also used the same Perma-Proto trick as before to make power rails for all the NeoPixel strips. But feel free to improvise with whatever supplies and techniques are available.

OPTIONAL: when possible, I like to build projects to be reconfigured or dismantled and used in other things…so, each of my 7 NeoPixel icicles has a 3-pin JST-SM connector at the end.

JST-SM connectors are not water resistant. Fine for indoors, or under house eaves if weather allows. If installing your project further out…on a tree, in the snow, etc., there are waterproof connectors better suited to this (and you’ll want good adhesive-lined heat-shrink tubing for waterproof connections). Or forego the connectors and wire everything in permanently.


An inordinate amount of wire was involved!

The Feather hardware resides at one corner of a window. The first NeoPixel strip needs only short wires, but each successive strip requires a few inches more than the previous one, then last one spanning all the way across (almost 48"). Finally, one more set of wires down to the “drips” at the bottom.

Each strip requires 5V, ground and data wires. Multi-conductor ribbon cable makes this process more pleasant…found some color-coded 4-conductor wire on Amazon, cheap enough that I didn’t feel bad peeling off the 4th wire.


The project is powered through the Feather board’s USB port, so you’ll need a higher amperage USB power supply (such as a phone charger) or a capacious USB battery bank if the installation isn’t well suited to running a long USB cable.

Other Parts

As with the OOZE MASTER 3000 project, you will also need:

  • Soldering iron and related paraphernalia
  • Sundry craft supplies and tools; this will vary with how you decide to implement the project. There will almost certainly be hot glue involved…but you might also need some clear packing tape, heat-shrink tubing, zip ties, hobby wood or edge molding and more. On the next page I’ll show some things I found.

This guide was first published on Dec 07, 2019. It was last updated on Jun 17, 2024.

This page (Hardware) was last updated on Mar 08, 2024.

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