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Built-in project · Seeed XIAO RP2040

XIAO RP2040 NeoPixel

The XIAO RP2040 powers its own NeoPixel from GPIO 11 and fades it around the color wheel on GPIO 12. The whole build, a Seeed XIAO RP2040, runs here in your browser on the firmware below; open it in the editor to change the wiring or the code and run it again.

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The parts retail for about $10.40. On Mokxi they're free.

XIAO RP2040 NeoPixel · Seeed XIAO RP2040live0.000 s 0.00x
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The circuit itself, running here on the simulator. Press what can be pressed; click anything else to open it in the editor.

The code

The firmware exactly as the editor opens it. Change a line there and press Run: it compiles in the browser.

sketch.ino · Seeed XIAO RP2040
// NeoPixel: the XIAO RP2040's own RGB LED.
//
// The NeoPixel is a WS2812 on GPIO 12 (PIN_NEOPIXEL), and its supply is
// switched by GPIO 11 (NEOPIXEL_POWER): drive that HIGH first, or the LED
// stays dark however much data it is sent, as on the real board.

#include <Adafruit_NeoPixel.h>

Adafruit_NeoPixel pixel(1, PIN_NEOPIXEL, NEO_GRB + NEO_KHZ800);

void setup() {
  pinMode(NEOPIXEL_POWER, OUTPUT);
  digitalWrite(NEOPIXEL_POWER, HIGH);
  pixel.begin();
  pixel.setBrightness(60);
}

void loop() {
  for (long hue = 0; hue < 65536; hue += 2048) {
    pixel.setPixelColor(0, pixel.ColorHSV(hue));
    pixel.show();
    delay(40);
  }
}

Parts list

2 parts, plus the jumper wires. They retail for about $10.40; on Mokxi they're free.

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