Speech Recognition with Arduino and BitVoicer Server

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STEP 2: Uploading the code to the Arduino

Now you have to upload the code below to your Arduino. You can also download the Arduino sketch from the link at the bottom. Before you upload the code, you must properly install the BitVoicer Server libraries into the Arduino IDE (Importing a .zip Library).

#include <BVSP.h>
#include <BVSMic.h>

// Defines the Arduino pin that will be used to capture audio 
#define BVSM_AUDIO_INPUT 5

// Defines the LED pins
#define RED_LED_PIN 6
#define YELLOW_LED_PIN 9
#define GREEN_LED_PIN 10

// Defines the constants that will be passed as parameters to 
// the BVSP.begin function
const unsigned long STATUS_REQUEST_TIMEOUT = 1000;
const unsigned long STATUS_REQUEST_INTERVAL = 2000;

// Defines the size of the audio buffer 
const int AUDIO_BUFFER_SIZE = 64;

// Defines the size of the receive buffer
const int RECEIVE_BUFFER_SIZE = 2;

// Initializes a new global instance of the BVSP class 
BVSP bvsp = BVSP();

// Initializes a new global instance of the BVSMic class 
BVSMic bvsm = BVSMic();

// Creates a buffer that will be used to read recorded samples 
// from the BVSMic class 
byte audioBuffer[AUDIO_BUFFER_SIZE];

// Creates a buffer that will be used to read the commands sent
// from BitVoicer Server.
// Byte 0 = pin number
// Byte 1 = pin value
byte receiveBuffer[RECEIVE_BUFFER_SIZE];

void setup() 
{
  // Sets up the pin modes
  pinMode(RED_LED_PIN, OUTPUT);
  pinMode(YELLOW_LED_PIN, OUTPUT);
  pinMode(GREEN_LED_PIN, OUTPUT);
  
  // Starts serial communication at 115200 bps 
  Serial.begin(115200); 
  
  // Sets the Arduino serial port that will be used for 
  // communication, how long it will take before a status request 
  // times out and how often status requests should be sent to 
  // BitVoicer Server. 
  bvsp.begin(Serial, STATUS_REQUEST_TIMEOUT, STATUS_REQUEST_INTERVAL);
    
  // Defines the function that will handle the frameReceived 
  // event 
  bvsp.frameReceived = BVSP_frameReceived; 
  
  // Prepares the BVSMic class timer 
  bvsm.begin();
}

void loop() 
{
  // Checks if the status request interval has elapsed and if it 
  // has, sends a status request to BitVoicer Server 
  bvsp.keepAlive();
  
  // Checks if there is data available at the serial port buffer 
  // and processes its content according to the specifications 
  // of the BitVoicer Server Protocol 
  bvsp.receive();

  // Checks if there is one SRE available. If there is one, 
  // starts recording.
  if (bvsp.isSREAvailable()) 
  {
    // If the BVSMic class is not recording, sets up the audio 
    // input and starts recording 
    if (!bvsm.isRecording)
    {
      bvsm.setAudioInput(BVSM_AUDIO_INPUT, EXTERNAL); 
      bvsm.startRecording();
    }

    // Checks if the BVSMic class has available samples 
    if (bvsm.available)
    {
      // Makes sure the inbound mode is STREAM_MODE before 
      // transmitting the stream
      if (bvsp.inboundMode == FRAMED_MODE)
        bvsp.setInboundMode(STREAM_MODE); 
        
      // Reads the audio samples from the BVSMic class
      int bytesRead = bvsm.read(audioBuffer, AUDIO_BUFFER_SIZE);
      
      // Sends the audio stream to BitVoicer Server
      bvsp.sendStream(audioBuffer, bytesRead);
    }
  }
  else
  {
    // No SRE is available. If the BVSMic class is recording, 
    // stops it.
    if (bvsm.isRecording)
      bvsm.stopRecording();
  }
}

// Handles the frameReceived event 
void BVSP_frameReceived(byte dataType, int payloadSize) 
{
  // Checks if the received frame contains binary data
  // 0x07 = Binary data (byte array)
  if (dataType == DATA_TYPE_BINARY)
  {
    // If 2 bytes were received, process the command.
    if (bvsp.getReceivedBytes(receiveBuffer, RECEIVE_BUFFER_SIZE) == 
      RECEIVE_BUFFER_SIZE)
    {
      analogWrite(receiveBuffer[0], receiveBuffer[1]);
    }
  }
}

This sketch has four major parts:

  • Library references and variable declaration: The first two lines include references to the BVSP and BVSMic libraries. These libraries are provided by BitSophia and can be found in the BitVoicer Server installation folder. The other lines declare constants and variables used throughout the sketch. The BVSP class is used to communicate with BitVoicer Server and the BVSMic class is used to capture and store audio samples.
  • Setup function: This function initializes serial communication, the BVSP class, the BVSMic class and sets the “event handler” (it is actually a function pointer) for the frameReceived event.
  • Loop function: This function performs three important actions: requests status info to the server (keepAlive() function), checks if the server has sent any data and processes the received data (receive() function), and controls the recording and sending of audio streams (isSREAvailable(), startRecording(), stopRecording() and sendStream() functions).
  • BVSP_frameReceived function: This function is called every time the receive() function identifies that one complete frame has been received. Here I run the command sent from BitVoicer Server. The command contains 2 bytes. The first byte indicates the pin and the second byte indicates the pin value. I use the analogWrite() function to set the appropriate value to the pin.

BVS_Demo1.ino (3.45 KB)