WS2812B LED strip with Seeed XIAO ESP32S3

A XIAO ESP32S3 can drive hundreds of WS2812B LEDs; what it can’t do is power them. Send data from D1 through 330 Ω, and give the strip its own 5 V adapter with the grounds joined.

The sketch runs a rainbow at about 25 % brightness.

Wiring

Also needed: 330 Ω resistor, 1000 µF / 10 V capacitor, 5 V 2 A adapter.

Every connection
XIAO ESP32S3	WS2812B addressable RGB LED strip (NeoPixel)	Wire	Notes
D1	DIN	green	Via 330 Ω
5 V 2 A adapter · +5V	5V	red	1000 µF capacitor across 5V/GND at the strip.
5 V 2 A adapter · GND	GND	black
GND	GND	black	Common ground with the XIAO.

5 V (about 60 mA per LED at full white) part, 3.3 V board. The strip expects a data HIGH of about 3.5 V at 5 V supply. From ESP32 or Pico the 3.3 V signal often works with short wires, but to be safe drive DIN through a 74AHCT125 (or 74HCT125) powered from 5 V.

Board quirks

The XIAO S3’s 5V pin is USB VBUS — fine for a few LEDs, but it reads 0 V on battery and feeding 5 V back into it needs a diode. A separate supply avoids both problems.
D1 (GPIO2) has no boot role. On the Sense board avoid D8–D10, which the SD-card slot shares.
The XIAO S3 has no on-board RGB LED, only the orange user LED on GPIO21.

Code

ws2812b-xiaos3.inoArduino C++Open in Playground Flash

// WS2812B strip on a Seeed XIAO ESP32S3.
// DIN → D1 (GPIO2) through 330 Ω. Strip 5V/GND → its own 5 V supply; supply GND → XIAO GND.
#include <Adafruit_NeoPixel.h>

constexpr uint16_t COUNT = 30;
Adafruit_NeoPixel strip(COUNT, D1, NEO_GRB + NEO_KHZ800);

void setup() {
  Serial.begin(115200);
  uint32_t t0 = millis();
  while (!Serial && millis() - t0 < 3000) {}
  strip.begin();
  strip.setBrightness(60);
  strip.show();
  Serial.printf("WS2812B: %u LEDs on D1\n", COUNT);
}

void loop() {
  static uint16_t hue = 0;
  for (uint16_t i = 0; i < COUNT; i++) {
    strip.setPixelColor(i, strip.gamma32(strip.ColorHSV(hue + i * 65536UL / COUNT)));
  }
  strip.show();
  hue += 256;
  delay(20);
}

// WS2812B strip on a Seeed XIAO ESP32S3.
// DIN → D1 (GPIO2) through 330 Ω. Strip 5V/GND → its own 5 V supply; supply GND → XIAO GND.
#include <Adafruit_NeoPixel.h>

constexpr uint16_t COUNT = 30;
Adafruit_NeoPixel strip(COUNT, D1, NEO_GRB + NEO_KHZ800);

void setup() {
  Serial.begin(115200);
  uint32_t t0 = millis();
  while (!Serial && millis() - t0 < 3000) {}
  strip.begin();
  strip.setBrightness(60);
  strip.show();
  Serial.printf("WS2812B: %u LEDs on D1\n", COUNT);
}

void loop() {
  static uint16_t hue = 0;
  for (uint16_t i = 0; i < COUNT; i++) {
    strip.setPixelColor(i, strip.gamma32(strip.ColorHSV(hue + i * 65536UL / COUNT)));
  }
  strip.show();
  hue += 256;
  delay(20);
}

Library: Adafruit NeoPixel (Adafruit) — compiled with Adafruit NeoPixel 1.15.5.

Expected serial output

Serial Monitor · 115200Output

WS2812B: 30 LEDs on D1

WS2812B: 30 LEDs on D1

Common errors

Nothing lights

Missing common GND, or data into DOUT. The arrows on the strip point away from DIN.

XIAO resets at full brightness

The strip is sharing the XIAO’s supply. Brownout fix.