REV A · LED-CTRL-01 · ESP32 / ESP8266

WLED Strip Planner

WLED is free, open-source firmware that turns a cheap ESP32 or ESP8266 Wi-Fi board into a controller for addressable LED strips, with a browser interface, an effects library, and hooks for home automation and light shows. The project's own docs cover getting it running. A lot of first-project questions turn out to be about power and wiring, so this page starts there: describe your strip and it does the arithmetic.

U1 Planner

Strip type

Strip volts

mA per pixel, full white

Length (m)

Pixels per m

Brightest you'll really run: % Supply headroom: %

Feed power every (m)

Data outputs

Feed wire

Wire run, one way (m)

Pixels
Worst case, full white
At your brightness
Supply to buy
WLED max current
Power feeds
Current per feed
Drop in each feed wire
Pixels per output
Max frame rate

How it works it out

J1 Wiring for your strip

Power (+)Ground, shared by everythingData, one way only

One ground for all. The supply, the board, and every feed point share ground. Data is measured against ground, so a board on a separate supply with no common ground gives garbage colours or nothing.
Data has a direction. Strips have arrows printed on them. The controller connects to the input end; feeding the wrong end does nothing.
Lift the data line. ESP boards talk at 3.3 V and 5 V pixels expect close to 5 V. It often works anyway, until it doesn't. A 74AHCT125 or 74HCT125 level shifter between board and strip is the usual fix for a first pixel that flickers or a strip that ignores you. WLED's own wiring guide covers it.
A resistor and a capacitor. A small resistor (a few hundred ohms) in the data line near the first pixel damps ringing, and a large capacitor across the supply at the strip's start soaks up the surge at switch-on. Builders differ on values; both are cheap insurance, not magic.
Feed power, not data, along the way. The thin copper on a strip drops voltage over distance, so the far end goes dim and orange. Extra feeds (power injection) connect + and ground at intervals; the data line stays single.
Fuse each feed. Thin wire carrying many amps from a big supply is how strips start melting. A fuse sized to the wire on each feed protects it.
Don't power a strip through the board. A board's 5 V pin passes current through its USB port and small parts. If you must, keep WLED's limit under about 1 A.

R1 WLED, the software

Pick a board. Both ESP8266 and ESP32 boards run WLED. The ESP32 is the safer pick for a new build: more memory, more LED outputs, more headroom for add-ons.
Flash it. WLED's project page links a web installer that flashes the board over USB from a browser that supports Web Serial, with no toolchain to set up.
Join it to Wi-Fi. A fresh install starts its own access point. Connect to it, give it your network's details, and it reboots onto your Wi-Fi.
Tell it about the strip. In the LED settings: the data pin, the LED type, the pixel count, and the brightness limiter's two numbers from the planner above (supply current and mA per pixel).
Play. Pick an effect and a palette from a phone or browser. Save what you like as a preset.

TP Sources and limits

WLED knowledge base: the project's own documentation, including LED settings and wiring guides for level shifters.
WLED on GitHub: source code and the feature list (segments, presets, sync, and the streaming protocols).
The per-pixel figures in the planner are common ratings, not measurements. Strips from different makers draw differently, and WS2815 figures in particular vary from one datasheet and seller to the next. Use your seller's watts-per-metre or a meter at full white if you have them.
The feed spacing defaults (about 2 m on 5 V, 5 m on 12 V) are starting rules of thumb. Check the far end at full white: if it shifts toward orange or pink, add a feed.
Wire drop uses copper's resistance per metre at room temperature for each gauge, out and back. It does not account for connectors, which often add more drop than the wire.