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ESP32-S3-DevKitC-1

First Blink (RGB LED)

The ESP32-S3-DevKitC-1 includes an addressable RGB LED (WS2812 / SK6812 compatible) that can display any color.

LED Details

SpecificationValue
TypeSK68XXMINI-HS (WS2812 compatible)
Control GPIO38 (V1.1) / 48 (V1.0)
ProtocolSingle-wire, 800 kHz
Color Depth24-bit (8-bit per channel)

This basic example toggles the LED data pin. The LED will appear dim white/off:

#include <Arduino.h>


#define LED_PIN 38  // Change to 48 for V1.0


void setup() {
    pinMode(LED_PIN, OUTPUT);
}


void loop() {
    digitalWrite(LED_PIN, HIGH);
    delay(500);
    digitalWrite(LED_PIN, LOW);
    delay(500);
}

  1. Add library dependency

    Add to platformio.ini:

    lib_deps = adafruit/Adafruit NeoPixel@^1.12.0

  2. Basic color cycling

    #include <Arduino.h>
    #include <Adafruit_NeoPixel.h>
    

    #define LED_PIN 38      // GPIO38 for V1.1
    #define NUM_LEDS 1
    

    Adafruit_NeoPixel strip(NUM_LEDS, LED_PIN, NEO_GRB + NEO_KHZ800);
    

    void setup() {
        strip.begin();
        strip.setBrightness(50);  // 0-255, start dim
        strip.show();  // Initialize all pixels to off
    }
    

    void loop() {
        // Red
        strip.setPixelColor(0, strip.Color(255, 0, 0));
        strip.show();
        delay(1000);
    

        // Green
        strip.setPixelColor(0, strip.Color(0, 255, 0));
        strip.show();
        delay(1000);
    

        // Blue
        strip.setPixelColor(0, strip.Color(0, 0, 255));
        strip.show();
        delay(1000);
    

        // White
        strip.setPixelColor(0, strip.Color(255, 255, 255));
        strip.show();
        delay(1000);
    }

Rainbow Effect

#include <Arduino.h>
#include <Adafruit_NeoPixel.h>


#define LED_PIN 38
#define NUM_LEDS 1


Adafruit_NeoPixel strip(NUM_LEDS, LED_PIN, NEO_GRB + NEO_KHZ800);


void setup() {
    strip.begin();
    strip.setBrightness(30);
}


void loop() {
    static uint16_t hue = 0;


    // Use HSV color space for smooth rainbow
    uint32_t color = strip.gamma32(strip.ColorHSV(hue));
    strip.setPixelColor(0, color);
    strip.show();


    hue += 256;  // Increment hue
    delay(20);
}

ESP-IDF Native LED Strip

Using ESP-IDF’s RMT peripheral for precise timing:

#include "led_strip.h"


#define LED_PIN 38
#define LED_COUNT 1


static led_strip_handle_t led_strip;


void app_main(void) {
    led_strip_config_t strip_config = {
        .strip_gpio_num = LED_PIN,
        .max_leds = LED_COUNT,
    };


    led_strip_rmt_config_t rmt_config = {
        .resolution_hz = 10 * 1000 * 1000,  // 10MHz
    };


    ESP_ERROR_CHECK(led_strip_new_rmt_device(&strip_config, &rmt_config, &led_strip));


    // Clear LED
    led_strip_clear(led_strip);


    while (1) {
        // Set to red
        led_strip_set_pixel(led_strip, 0, 255, 0, 0);
        led_strip_refresh(led_strip);
        vTaskDelay(pdMS_TO_TICKS(1000));


        // Set to green
        led_strip_set_pixel(led_strip, 0, 0, 255, 0);
        led_strip_refresh(led_strip);
        vTaskDelay(pdMS_TO_TICKS(1000));


        // Set to blue
        led_strip_set_pixel(led_strip, 0, 0, 0, 255);
        led_strip_refresh(led_strip);
        vTaskDelay(pdMS_TO_TICKS(1000));
    }
}

FastLED Alternative

#include <FastLED.h>


#define LED_PIN 38
#define NUM_LEDS 1
#define BRIGHTNESS 50


CRGB leds[NUM_LEDS];


void setup() {
    FastLED.addLeds<WS2812, LED_PIN, GRB>(leds, NUM_LEDS);
    FastLED.setBrightness(BRIGHTNESS);
}


void loop() {
    // Cycle through hues
    static uint8_t hue = 0;
    leds[0] = CHSV(hue++, 255, 255);
    FastLED.show();
    delay(20);
}

Status Indicator Patterns

Use the LED to indicate device state:

#include <Adafruit_NeoPixel.h>


#define LED_PIN 38
Adafruit_NeoPixel led(1, LED_PIN, NEO_GRB + NEO_KHZ800);


void setStatus(const char* status) {
    uint32_t color;


    if (strcmp(status, "wifi_connected") == 0) {
        color = led.Color(0, 255, 0);  // Green
    } else if (strcmp(status, "wifi_connecting") == 0) {
        color = led.Color(255, 165, 0);  // Orange
    } else if (strcmp(status, "error") == 0) {
        color = led.Color(255, 0, 0);  // Red
    } else if (strcmp(status, "ota_update") == 0) {
        color = led.Color(0, 0, 255);  // Blue
    } else {
        color = led.Color(0, 0, 0);  // Off
    }


    led.setPixelColor(0, color);
    led.show();
}


void pulseStatus(uint32_t color, int duration_ms) {
    for (int i = 0; i < 255; i += 5) {
        led.setBrightness(i);
        led.setPixelColor(0, color);
        led.show();
        delay(duration_ms / 100);
    }
    for (int i = 255; i > 0; i -= 5) {
        led.setBrightness(i);
        led.setPixelColor(0, color);
        led.show();
        delay(duration_ms / 100);
    }
}

Troubleshooting

LED Stays Off

  1. Check GPIO number (38 for V1.1, 48 for V1.0)
  2. Verify library is using correct color order (GRB vs RGB)
  3. Set brightness above 0

Colors Are Wrong

The LED uses GRB color order:

// Correct for DevKitC-1
Adafruit_NeoPixel strip(1, LED_PIN, NEO_GRB + NEO_KHZ800);


// Wrong order
Adafruit_NeoPixel strip(1, LED_PIN, NEO_RGB + NEO_KHZ800);

LED Flickers

  • Reduce brightness
  • Add a 300-500Ω resistor in series with data line
  • Ensure stable power supply

Next Steps