diff --git a/src/main.cpp b/src/main.cpp
index 5770874..c3986eb 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -9,12 +9,14 @@
 
 #include "keyboard.h"
 #include "sdcard.h"
+#include "sound.h"
 
 #define VERSION "0.0"
 #define LED_PIN 21
 
 Keyboard keyboard;
 SDCard sdcard;
+Sound sound;
 
 void setup()
 {
@@ -29,6 +31,7 @@ void setup()
 
   keyboard.init();
   sdcard.mount();
+  sound.init();
 }
 
 void loop()
@@ -43,9 +46,11 @@ void loop()
     if (touched == true) {
       // turn the LED on (HIGH is the voltage level)
       digitalWrite(LED_PIN, HIGH);
+      sound.play();
     } else {
       // turn the LED off by making the voltage LOW
       digitalWrite(LED_PIN, LOW);
+      sound.stop();
     }
 
 
diff --git a/src/sound.cpp b/src/sound.cpp
new file mode 100644
index 0000000..ef5ecd9
--- /dev/null
+++ b/src/sound.cpp
@@ -0,0 +1,86 @@
+/*
+ * i2s
+ *
+ * http://esp-idf.readthedocs.io/en/latest/api/peripherals/i2s.html
+ * https://github.com/espressif/esp-idf/blob/375b28650bd1c90d6ac706f63cde9a64d9a7e3e5/examples/peripherals/i2s/main/i2s_example_main.c
+ */
+
+#include "sound.h"
+
+#include "Arduino.h"
+#include <stdio.h>
+#include "freertos/FreeRTOS.h"
+#include "freertos/task.h"
+#include "driver/i2s.h"
+//#include <soc/i2s_reg.h>
+#include <math.h>
+
+
+#define SAMPLE_RATE     (36000)
+#define WAVE_FREQ_HZ    (100)
+//#define PI 3.14159265
+
+#define SAMPLE_PER_CYCLE (SAMPLE_RATE/WAVE_FREQ_HZ)
+
+
+using namespace std;
+
+Sound::Sound() {
+}
+
+void Sound::init() {
+    unsigned int i, sample_val;
+    float sin_float, triangle_float, triangle_step = 65536.0 / SAMPLE_PER_CYCLE;
+    //for 36Khz sample rates, we create 100Hz sine wave, every cycle need 36000/100 = 360 samples (4-bytes each sample)
+    //using 6 buffers, we need 60-samples per buffer
+    //2-channels, 16-bit each channel, total buffer is 360*4 = 1440 bytes
+    i2s_config_t i2s_config;
+    i2s_config.mode = (i2s_mode_t) (I2S_MODE_MASTER | I2S_MODE_TX);		// Only TX
+    i2s_config.sample_rate = SAMPLE_RATE;
+    i2s_config.bits_per_sample = (i2s_bits_per_sample_t)16;			//16-bit per channel
+    i2s_config.channel_format = I2S_CHANNEL_FMT_RIGHT_LEFT;			//2-channels
+    i2s_config.communication_format = (i2s_comm_format_t) (I2S_COMM_FORMAT_I2S | I2S_COMM_FORMAT_I2S_MSB);
+    i2s_config.dma_buf_count = 6;
+    i2s_config.dma_buf_len = 60;						//
+    i2s_config.intr_alloc_flags = ESP_INTR_FLAG_LEVEL1;				//Interrupt level 1
+
+    i2s_pin_config_t pin_config = {
+        .bck_io_num = 26,
+        .ws_io_num = 25,
+        .data_out_num = 22,
+        .data_in_num = -1                                                       //Not used
+    };
+
+    i2s_driver_install(i2s_num, &i2s_config, 0, NULL);
+    i2s_set_pin(i2s_num, &pin_config);
+
+    triangle_float = -32767;
+
+    for(i = 0; i < SAMPLE_PER_CYCLE; i++) {
+        sin_float = sin(i * PI / 180.0);
+        if(sin_float >= 0)
+            triangle_float += triangle_step;
+        else
+            triangle_float -= triangle_step;
+        sin_float *= 32767;
+
+        sample_val = 0;
+        sample_val += (short)triangle_float;
+        sample_val = sample_val << 16;
+        sample_val += (short) sin_float;
+ 
+        i2s_push_sample(i2s_num, (char *)&sample_val, portMAX_DELAY);
+    }
+}
+
+void Sound::play() {
+  i2s_start(i2s_num);
+}
+
+void Sound::stop() {
+  i2s_stop(i2s_num);
+}
+
+void Sound::end() {
+  i2s_driver_uninstall(i2s_num); //stop & destroy i2s driver
+}
diff --git a/src/sound.h b/src/sound.h
new file mode 100644
index 0000000..d41763d
--- /dev/null
+++ b/src/sound.h
@@ -0,0 +1,33 @@
+#ifndef _SOUND_H
+#define _SOUND_H
+
+#include "Arduino.h"
+
+#include "driver/i2s.h"
+
+#define I2S_NUM 0
+
+
+typedef struct {
+  int16_t buf[512];
+  int len;
+  int index;
+  int playing;
+} i2sbuffer_t;
+
+class Sound {
+  public:
+    Sound();
+    void init();
+    void end();
+    void loop();
+//    void close();
+    void play();
+//    void pause();
+    void stop();
+  private:
+    i2sbuffer_t buffer;
+    const i2s_port_t i2s_num = (i2s_port_t)I2S_NUM;
+};
+
+#endif /* _SOUND_H */