Hardware¶

What to connect between an ESP32 and a WS2812B strip, the signal it expects, and how to power it.

The numbers here come from the Worldsemi WS2812B datasheet and, for the original WS2812, the WS2812 datasheet. Clones and later revisions differ; check the datasheet of the LEDs you bought.

Pins¶

Pin	Name	Connect to
1	VDD	5 V supply (3.5 V to 5.3 V)
2	DOUT (out)	DIN of the next LED
3	VSS	Supply ground and ESP32 ground
4	DIN (in)	ESP32 GPIO, through a level shifter

A strip brings out VDD (often labelled 5V or +), DIN and GND at its input end. The data goes one way: connect the end marked DIN or with the arrow pointing away from the connector.

The ESP32 side¶

Setting	Value	Notes
Peripheral	One RMT transmit channel	Chosen by ESP-IDF's RMT driver; the `channel` argument is unused
GPIO	Any output-capable GPIO	GPIO8 in the examples (ESP32-C6)
Resolution	10 MHz, 100 ns per tick	Fixed by `WS2812Strip`
Symbol memory	One block (64 symbols on ESP32/S2, 48 on S3/C3/C6/H2), no DMA	Refilled by interrupt while a frame is sent
Output level	3.3 V	Below the WS2812B's 3.5 V high threshold at 5 V

Signal¶

The LEDs read one line, non-return-to-zero at 800 kbit/s. Every bit is a high pulse followed by a low one; the length of the high pulse decides 0 or 1. Each LED keeps the first 24 bits it receives and passes the rest on through DOUT, reshaped. A low line for longer than the reset time latches the new colours into every LED.

Parameter	WS2812B	Driver (100 ns ticks)
T0H, 0 bit high	0.40 µs ±150 ns	4: 0.4 µs
T1H, 1 bit high	0.80 µs ±150 ns	8: 0.8 µs
T0L, 0 bit low	0.85 µs ±150 ns	9: 0.9 µs
T1L, 1 bit low	0.45 µs ±150 ns	5: 0.5 µs
TH + TL	1.25 µs ±600 ns	1.3 µs
Reset, line low	more than 50 µs (WS2812B-V5: at least 280 µs)	300 µs after every frame (reset)
Bit order	G7 ... G0, R7 ... R0, B7 ... B0	Green byte first from a `0xRRGGBB` pixel, MSB first

The original WS2812 specifies 0.35, 0.7, 0.8 and 0.6 µs, each ±150 ns, and the same reset and order; the driver values above fall inside both parts' windows. The driver column is the Kconfig default and what the examples on this site pass to the constructor (Configuration).

sequenceDiagram
    participant E as ESP32 (RMT)
    participant L0 as LED 0
    participant L1 as LED 1
    E->>L0: 24 bits for LED 0, then 24 for LED 1
    L0->>L0: keep the first 24 bits
    L0->>L1: forward the rest through DOUT
    E->>L0: reset: line low for 300 µs
    L0->>L0: latch: new colour shows
    L1->>L1: latch: new colour shows

Signal timing turns these numbers into ticks, frame times and memory.

Logic levels¶

Parameter	WS2812B	At VDD = 5 V
VIH, input high	0.7 × VDD minimum	3.5 V
VIL, input low	0.3 × VDD maximum	1.5 V
Input voltage	−0.5 V to VDD + 0.5 V

3.3 V data into a 5 V strip

An ESP32's 3.3 V high is under the 3.5 V the datasheet asks for. Many strips accept it on a short wire, some do not, and the margin shrinks with temperature and cable length. Use a buffer powered from 5 V that accepts 3.3 V inputs (74AHCT125, 74HCT245) between the GPIO and DIN.

Power¶

Item	Value	Source
VDD	3.5 V to 5.3 V	WS2812B datasheet
Current at full white	About 60 mA per LED	Three LEDs at 20 mA each, from the WS2812 datasheet; the WS2812B datasheet gives no figure
Decoupling	100 nF at each LED	WS2812B application circuit (most strips have it)
Operating temperature	−25 °C to +80 °C	WS2812B datasheet

Budget the supply for the strip: 60 LEDs at full white is about 3.6 A. Brightness scaling lowers it in proportion. Feed long strips from both ends or every metre or so, so the far LEDs do not dim or shift colour.

Adafruit's NeoPixel guide adds two parts that protect the first LED: a 300 Ω to 500 Ω resistor in series with DIN, close to the strip, and a large capacitor (1000 µF or so) across the supply at the strip input. Connect the ground before the supply, and power the strip before or with the ESP32, never drive DIN of an unpowered strip.

Reference documents¶

Document	What it is for
WS2812B datasheet (Worldsemi)	Pins, supply, input levels, bit timing, data order
WS2812 datasheet (Worldsemi)	The original six-pin part: its timing and per-colour current
ESP-IDF RMT documentation	Channels, symbol memory, DMA and the encoder model
Adafruit NeoPixel guide	Wiring and power practice