> ## Documentation Index
> Fetch the complete documentation index at: https://docs.kode.diy/llms.txt
> Use this file to discover all available pages before exploring further.

# Speaker

# Features

The Kode Dot integrates a **1W speaker connected to an amplifier.** Thus, you only have to worry about giving sound to your projects through the I2S bus and the amplifier will take care of doing all the work.

## Connection diagram

The speaker is connected to the ESP32-S3 as follows:

| Speaker | ESP32-S3 |
| ------- | -------- |
| SCK     | GPIO38   |
| WS      | GPIO45   |
| DOUT    | GPIO46   |
| SD      | EXP3     |

<Note>The amplifier is off by default to not waste energy. To turn it on, set the EXP3 pin of the [IO expander](/en/kode-dot/io-expander) to HIGH.</Note>

## Recommended libraries

### Arduino

* [ESP\_I2S](https://github.com/espressif/arduino-esp32/blob/master/libraries/ESP_I2S)
* [ESP32\_IO\_Expander](https://github.com/esp-arduino-libs/ESP32_IO_Expander)

### ESP-IDF

* [ESP-ADF](https://github.com/espressif/esp-adf)
* [esp\_io\_expander\_tca95xx\_16bit](https://components.espressif.com/components/espressif/esp_io_expander_tca95xx_16bit)

<Warning>The use of ESP-ADF is for advanced users. If you do not have experience in this framework, we recommend using the Arduino library.</Warning>

## Example code

This code **reproduces the tone specified in the `frequency` variable.**

```cpp speaker_tone.ino lines icon="microchip" theme={null}
/**
 * Generates a square-wave tone over I2S (48 kHz, 32-bit, mono) and enables the amplifier via an I/O expander.
 * The tone streams continuously through I2S; the expander powers the audio stage.
 * Uses custom pins for I2S and for the TCA95XX_16BIT expander.
*/
/* ───────── KODE | docs.kode.diy ───────── */

#include <ESP_I2S.h>
#include <esp_io_expander.hpp>

/* Expander pin configuration */
#define I2C_SCL_PIN     (47)
#define I2C_SDA_PIN     (48)
#define I2C_ADDR        (0x20)

/* I2S interface pins */
const uint8_t I2S_SCK   = 38;  // Serial clock (SCK)
const uint8_t I2S_WS    = 45;  // Word Select / LRCLK
const uint8_t I2S_DOUT  = 46;  // Data output (SD)

/* Audio signal parameters */
const int frequency   = 300;    // Square wave frequency in Hz
const int amplitude   = 500;    // Square wave amplitude

/* Signal generation state variables */
int32_t sample = amplitude;  // Current sample value
int count = 0;               // Sample counter

/* Global instances */
I2SClass i2s;                // I2S interface object
esp_expander::Base *expander = nullptr;  // Expander instance pointer

void setup() {
  Serial.begin(115200);
  Serial.println("Simple I2S tone");

  /* Configure I2S pins (no MCLK: pass -1) */
  i2s.setPins(I2S_SCK, I2S_WS, I2S_DOUT, -1);

  /* Initialize I2S: standard mode, 48 kHz, 32-bit, mono, left slot */
  if (!i2s.begin(I2S_MODE_STD, 48000, I2S_DATA_BIT_WIDTH_32BIT,
                 I2S_SLOT_MODE_MONO, I2S_STD_SLOT_LEFT)) {
    Serial.println("Failed to initialize I2S!");
    while (1);  // Halt on failure
  }
  Serial.println("I2S bus initialized.");

  /* Initialize the I/O expander */
  expander = new esp_expander::TCA95XX_16BIT(I2C_SCL_PIN, I2C_SDA_PIN, I2C_ADDR);
  expander->init();
  expander->begin();

  /* Set expander pin 3 as output to enable the amplifier */
  expander->pinMode(3, OUTPUT);
  expander->digitalWrite(3, HIGH); /* Enable amplifier */
}

void loop() {
  /* Toggle sign every half wavelength to create a square wave */
  if (count % (48000/(2*frequency)) == 0) {
    sample = -sample;
  }

  /* Write the sample (mono) */
  i2s.write(sample); // Left channel

  /* Increment sample counter */
  count++;
}
```

## Download examples

You can test the example codes using the Arduino IDE or the ESP-IDF IDE or download the codes in our drive:

[Audio examples](https://drive.google.com/drive/folders/1rJPxfOXun4p1ijXyRdREydyOMEUJju0u)