====== Buzzer example ======
{{:en:iot:examples:soundmodule.png?200|}}

Needed libraries:
<code>lib_deps = ITTIoT, gmarty2000/Buzzer@^1.0.0</code>

The code below will alert the buzz sound when values have been submitted by the mqtt server

<code c>

/*
 * IoT Buzzer example
 *
 * This example subscribe to the "buzzer" topic. When a message received, then it
 * will make a sound
 *
 * Created 02 Febrary 2018 by Heiko Pikner
 */

// Includes global variables and librarys that the Buzzer uses
#include <Arduino.h>
#include <ittiot.h>
#include <Buzzer.h>

#define MODULE_TOPIC "ESP30/buzzer"
#define WIFI_NAME "name"
#define WIFI_PASSWORD "password"

//Pin definition for the buzzer (GPIO15)
#define BUZZER_PIN D8

Buzzer buzzer(BUZZER_PIN);

// Splitting string into smaller parts, so that the sound level and length can be read out
// https://stackoverflow.com/questions/9072320/split-string-into-string-array
String getValue(String data, char separator, int index)
{
  int found = 0;
  int strIndex[] = {0, -1};
  int maxIndex = data.length()-1;

  for(int i=0; i<=maxIndex && found<=index; i++)
  {
    if(data.charAt(i)==separator || i==maxIndex)
    {
        found++;
        strIndex[0] = strIndex[1]+1;
        strIndex[1] = (i == maxIndex) ? i+1 : i;
    }
  }
  return found>index ? data.substring(strIndex[0], strIndex[1]) : "";
}

// If message received sound the buzz. For example:
// mosquitto_pub -u test -P test -t "ITT/IOT/3/buzzer" -m "49;100"
// The first message is the pitch(integer between 1-8191) and the second message is the duration
void iot_received(String topic, String msg)
{
  Serial.print("MSG FROM USER callback, topic: ");
  Serial.print(topic);
  Serial.print(" payload: ");
  Serial.println(msg);

  if(topic == MODULE_TOPIC)
  {
    String Note = getValue(msg,';',0);
    String time = getValue(msg,';',1);

    buzzer.sound(Note.toInt(),time.toInt());
  }
}

// Function started after the connection to the server is established.
void iot_connected()
{
  Serial.println("MQTT connected callback");
  // Subscribe to the topic "buzzer"
  iot.subscribe(MODULE_TOPIC);
  iot.log("IoT buzzer example!");
}

void setup()
{
  Serial.begin(115200); // setting up serial connection parameter
  Serial.println("Booting");

  //iot.setConfig("wname", WIFI_NAME);
  //iot.setConfig("wpass", WIFI_PASSWORD);
  // Print json config to serial
  iot.printConfig();
  // Initialize IoT library
  iot.setup();
}

//Main code, which runs in loop
void loop()
{
  // IoT behind the plan work, it should be periodically called
  iot.handle();
  delay(200); // Wait for 0.2 second
}

</code>