Decisions & Rationale

Key choices made during the build, and why.

IP65 for all LED strips

Decided: 2026-05-13

Alex reports that silicone-sleeved strips (IP67/68) trap heat on the playa — the sleeve doesn’t allow air circulation, leading to overheating. We’re using IP65 silicone-coated strips throughout. The coating protects against dust without trapping heat.

WS2815 12V for the rose window (supersedes WS2813 and GS8208 decisions)

Decided: 2026-05-18

Decision history:

WS2813 5V (2026-05-13) — dual data line, great chip, but 5V-only requiring buck converter
GS8208 24V (2026-05-17) — identified as only 24V chip at 60px/m; 24V IP65 not available from US suppliers; heat issue (~75W/m) also a concern
WS2815 12V (2026-05-18) — ✅ final choice

WS2815 is WS2813’s direct successor: dual data line (breakpoint resume), 60/m, 1 pixel per LED, widely available from BTF-Lighting on Amazon Prime. It runs at 12V natively — a purpose-designed voltage for the chip, with half the heat of GS8208 at 24V (~32W/m vs ~75W/m).

No converter needed: the rose window gets its own dedicated 12V PSU (Mean Well HLG-320H-12). The F48V5 differential signal to the SRx4 is power-independent, so the rose window can run at 12V while every other zone runs at 24V — the controller never knows or cares.

WS2813 for the rose window (original — superseded 2026-05-18)

Originally decided: 2026-05-13

WS2813’s dual data line = breakpoint resume. Chosen because the window is hard to service at height. Superseded by WS2815, which is the same chip design updated for 12V.

BTF-Lighting IP65 threaded barrel connectors throughout

Decided: 2026-05-14

Compared JST SM, GX16 aviation, WEIPU SP13, and BTF-Lighting threaded barrel:

JST SM — rejected. Bad playa experience: corrosion, pull-apart failure.
GX16 aviation — metal shell looks robust but IP55 only, lower than what we need.
WEIPU SP13 — IP68, excellent sealing, but expensive and no pre-terminated strip options.
BTF-Lighting threaded barrel (22mm, IP65) — ✅ chosen. Purpose-built for LED strips, pre-terminated options, mechanical lock, IP65, works with gloves, cheap, 3-pin and 4-pin variants available.

Standard: 3-pin for rose window (12V, V+/GND/DATA); 4-pin for all 24V zones (V+, GND, DATA, backup data).

Mixed voltage: 12V rose window, 24V everywhere else

Decided: 2026-05-18

The rest of the installation runs 24V (spires, arches, canopy, orbs). The rose window runs 12V on a dedicated PSU. This is clean and correct:

F48V5 differential signal over Cat6 carries no power — each SmartReceiver has its own power input
Rose window SRx4 powered at 12V; all other SmartReceivers powered at 24V
No converter anywhere — each zone is self-contained at its native voltage
Simpler and more reliable than running a converter at the window

Previous thinking tried to standardize on a single voltage. Mixed voltage per zone is actually the right architecture for a multi-zone installation with different strip types.

Zones illustration: Python OBJ projection, not Blender render

Decided: 2026-05-17

Needed a clean 2D illustration of all LED zones for the wiki. Two approaches tried:

Blender Freestyle SVG Exporter — produces line art directly from the 3D model. Got it working (render engine = BLENDER_EEVEE, Freestyle SVG Exporter extension enabled). Useful for full-model line drawings but hard to color individual zones independently.
Python OBJ projection (drawings/obj-to-svg.py) — reads per-zone OBJ files, projects vertices through the Blender camera matrix, produces an SVG with one named <g> layer per zone. Full control over color, fill, opacity, layering. Chosen approach.

Camera parameters baked into script from Blender console (location, rotation, focal length, sensor). PNG exported at 2× via cairosvg.

SK9822 SPI vs. WS2811 for arches

Status: PENDING — follow up with Alex + Sonic Runway artist.

SK9822 has a separate clock line (SPI), making it more debuggable in the field. A Sonic Runway artist recommended it. The cost premium at this scale is ~$4–6k. WS2811 24V is the budget-friendly default. Decision needed before strip ordering.

F48V5 + SmartReceiver architecture

Decided: 2026-05-09

One Falcon F48V5 as the central controller. SmartReceivers at each zone cluster, connected via Cat6 differential signal. Confirmed F48V5 ↔ SRx4 compatibility with David Pitts (pixelcontroller.com), 2026-05-13.