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Built-in project · ESP32-S3-DevKitC-1

ESP32-S3 rainbow

The DevKitC-1’s own RGB LED walking around the color wheel, one WS2812 frame from the RMT every 20 ms. The whole build, an ESP32-S3-DevKitC-1, 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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ESP32-S3 rainbow · ESP32-S3-DevKitC-1live0.000 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 · ESP32-S3-DevKitC-1
// Rainbow: the RGB LED on GPIO48 walks round the color wheel.
//
// rgbLedWrite(pin, red, green, blue) sends one WS2812 frame on RMT channel 0:
// twenty-four bits, green first, each a high pulse of 400 or 800 ns. The
// color holds until the next frame, so the sketch only has to send one
// every few milliseconds.

const int kLed = RGB_BUILTIN;

// One step round the wheel: 0..255 in, a color out, at full brightness / 4.
void wheel(int pos, int *r, int *g, int *b)
{
    pos = pos & 255;
    if (pos < 85) {
        *r = 255 - pos * 3;
        *g = pos * 3;
        *b = 0;
    } else if (pos < 170) {
        pos -= 85;
        *r = 0;
        *g = 255 - pos * 3;
        *b = pos * 3;
    } else {
        pos -= 170;
        *r = pos * 3;
        *g = 0;
        *b = 255 - pos * 3;
    }
    *r /= 4;
    *g /= 4;
    *b /= 4;
}

void setup()
{
    Serial.begin(115200);
    Serial.println("rainbow on the RGB LED, GPIO48");
}

void loop()
{
    for (int pos = 0; pos < 256; pos += 4) {
        int r, g, b;
        wheel(pos, &r, &g, &b);
        rgbLedWrite(kLed, r, g, b);
        delay(20);
    }
}

Parts list

2 parts, plus the jumper wires. Every one is in the editor's parts bin.

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