Published May 3, 2020 © MIT

VOICE CONTROLLED Car

This car is designed to be controlled by voice commands.

IntermediateProtip28,149

Things used in this project

Hardware components

Arduino UNO

Breadboard (generic)

DC Motor, 12 V

Pimoroni Maker Essentials - Micro-motors & Grippy Wheels

Voltage Regulator, DC/DC Gate Driver

Jumper wires (generic)

HC-05 Bluetooth Module

Bluetooth Low Energy (BLE) Module (Generic)

Texas Instruments Dual H-Bridge motor drivers L293D

Battery, 12 V

Software apps and online services

Arduino IDE

Story

The principle this toy concept was based on was voice recognition technology. The car operates by having a voice receiver box on it where it receives your voice commands. The car has a 50 foot radius from where it is initially place on the ground. The child interacts with the car by shouting out commands like "faster", "slower", "right", "left", and "stop". The child will be able to feel like they are in full control of the car by doing this, thus giving them the sense of being important. The child programs their own voice into the receiver so that only they can operate the car. The car has an emergency shut down when it reaches the boundary of the 50 foot radius. The child must also be within that 50 foot radius when shouting commands in order for the car to initiate the desired command.

The car is relatively cheap to produce because it's exterior is made of plastic. The voice recognition technology also is very cheap these days, and since the receiver only has to have a few words programmed into it, the cost is also reduced. As long as the car is not dropped from a 3 story window, the child would have no problem with its durability. It can withstand crashes against curbs and other such similar obstacles. There is no choking hazard risk in regards with this toy. The on/off switch is located in a safe area where the child's hands won't be near any moving parts. Also, there won't be any sharp edges on the car that can inadvertently cut the child.

Screenshot of the home screen of Voicecontrol app

The screenshot of Android App is given below. Android smartphone with an app is the transmitter end. Android speech-recognition app used here was developed using MIT App Inventor.
Initially there need to be pairing of Bluetooth HC-05/HC-06. Once pairing is done, then it need to be connected. When the app is running in the smartphone, the user’s voice commands are detected by the phone microphone.

Download the Android App from here: https://drive.google.com/file/d/1oUCzhqlGfX8yksw9UA553lBSEMAg5xu8/view

Circuit Diagram & Connections

The circuit consist of Arduino UNO Board, HC-05/HC-06 Bluetooth Module, L293D Motor Driver IC, a pair of DC Geared Motors of 200 RPM and a 9V Battery.

The TX, RX pins of Arduino is connected to Rx, Tx pins of Bluetooth Module. The Bluetooth Module is supplied with 5V. Similarly, left DC motor is connected to pin no 3 & 6 of L293D and right DC motor to pin no 14 & 11 of L293D. Arduino digital pins 3,4,5,6 is connected to L293D 2, 7, 10, 15 respectively.

The L293D IC Pins 2, 5, 12, 13 is GND pins and 9, 1, 16 is supplied with 5V. But pin 8 of L293D is directly supplied with 9V.

Ideas

Android smartphone with app. Android speech-recognition app (voicecontrol.apk) used here was developed using MIT App Inventor. When the app is running in the smartphone, user’s voice commands are detected by the microphone present in the phone.

Commands are processed, and speech-to-text conversion is done within the app using Google’s speech-recognition technology. Text is then sent to the receiver side (that is, robotic car) via Bluetooth.

Arduino Uno R3. Arduino Uno is an AVR ATmega328P microcontroller (MCU)-based development board with six analogue input pins and 14 digital I/O pins. The MCU has 32kB ISP flash memory, 2kB RAM and 1kB EEPROM. The board provides the capability of serial communication via UART, SPI and I2C. The MCU can operate at a clock frequency of 16MHz. In this project, digital I/O pins 2, 3, 4 and 5 of Arduino are configured as output pins. Pins 0 and 1 of Arduino are used for serial communication with HC-05 Bluetooth module.

Text received via Bluetooth is forwarded to Arduino Uno board using UART serial communication protocol. Arduino program voice_ctrl.ino checks the text received and, if it is a matching string, Arduino controls the movements of the robot accordingly. Voice commands used for controlling the robot and their functions are shown in Table I.

Working of the Project

As mentioned above Voice Commands are processed by phone, and speech-to-text conversion is done within the app using Google’s speech-recognition technology. Text is then sent to the receiver side via Bluetooth. Text received via Bluetooth is forwarded to Arduino Uno board using UART serial communication protocol. Arduino code checks the text received. Whenever the text is a matching string, Arduino controls the movements of the robot accordingly in forward, backward, Turning Right, Turning Left & Stop.

Signal logic levels at the different stages of the circuits for proper controlling of the robotic car are given below.

Code

Code

#include <SoftwareSerial.h>

SoftwareSerial BT(0, 1); //TX, RX respetively
String readvoice;

void setup() {
 BT.begin(9600);
 Serial.begin(9600);
  pinMode(4, OUTPUT);
  pinMode(3, OUTPUT);
  pinMode(5, OUTPUT);
  pinMode(6, OUTPUT);

}
//-----------------------------------------------------------------------// 
void loop() {
  while (BT.available()){  //Check if there is an available byte to read
  delay(10); //Delay added to make thing stable
  char c = BT.read(); //Conduct a serial read
  readvoice += c; //build the string- "forward", "reverse", "left" and "right"
  } 
  if (readvoice.length() > 0) {
    Serial.println(readvoice);

  if(readvoice == "*forward#")
  {
    digitalWrite(3, HIGH);
    digitalWrite (4, HIGH);
    digitalWrite(5,LOW);
    digitalWrite(6,LOW);
    delay(100);
  }

  else if(readvoice == "*back#")
  {
    digitalWrite(3, LOW);
    digitalWrite(4, LOW);
    digitalWrite(5, HIGH);
    digitalWrite(6,HIGH);
    delay(100);
  }

  else if (readvoice == "*left#")
  {
    digitalWrite (3,HIGH);
    digitalWrite (4,LOW);
    digitalWrite (5,LOW);
    digitalWrite (6,LOW);
   delay (800);
      digitalWrite(3, HIGH);
    digitalWrite (4, HIGH);
    digitalWrite(5,LOW);
    digitalWrite(6,LOW);
    delay(100);
  
  }

 else if ( readvoice == "*right#")
 {
   digitalWrite (3, LOW);
   digitalWrite (4, HIGH);
   digitalWrite (5, LOW);
   digitalWrite (6, LOW);
   delay (800);
      digitalWrite(3, HIGH);
    digitalWrite (4, HIGH);
    digitalWrite(5,LOW);
    digitalWrite(6,LOW);
    delay(100);
 }

 else if (readvoice == "*stop#")
 {
   digitalWrite (3, LOW);
   digitalWrite (4, LOW);
   digitalWrite (5, LOW);
   digitalWrite (6, LOW);
   delay (100);
 }
 else if (readvoice == "*keep watch in all direction#")
 {
   digitalWrite (3, HIGH);
   digitalWrite (4, LOW);
   digitalWrite (5, LOW);
   digitalWrite (6, LOW);
   delay (100);
 }
  else if (readvoice == "*show me Garba#")
 {
 digitalWrite (3, LOW);
   digitalWrite (4, HIGH);
   digitalWrite (5, LOW);
   digitalWrite (6, LOW);
   delay (400);
      digitalWrite(3, HIGH);
    digitalWrite (4, HIGH);
    digitalWrite(5,LOW);
    digitalWrite(6,LOW);
    delay(600);
    digitalWrite (3, LOW);
   digitalWrite (4, HIGH);
   digitalWrite (5, HIGH);
   digitalWrite (6, LOW);
   delay (500);
   digitalWrite (3, HIGH);
   digitalWrite (4, LOW);
   digitalWrite (5, LOW);
   digitalWrite (6, HIGH);
   delay (500);

digitalWrite (3, LOW);
   digitalWrite (4, HIGH);
   digitalWrite (5, LOW);
   digitalWrite (6, LOW);
   delay (400);
      digitalWrite(3, HIGH);
    digitalWrite (4, HIGH);
    digitalWrite(5,LOW);
    digitalWrite(6,LOW);
    delay(600);
    digitalWrite (3, LOW);
   digitalWrite (4, HIGH);
   digitalWrite (5, HIGH);
   digitalWrite (6, LOW);
   delay (500);
   digitalWrite (3, HIGH);
   digitalWrite (4, LOW);
   digitalWrite (5, LOW);
   digitalWrite (6, HIGH);
   delay (500);digitalWrite (3, LOW);
   digitalWrite (4, HIGH);
   digitalWrite (5, LOW);
   digitalWrite (6, LOW);
   delay (400);
      digitalWrite(3, HIGH);
    digitalWrite (4, HIGH);
    digitalWrite(5,LOW);
    digitalWrite(6,LOW);
    delay(600);
    digitalWrite (3, LOW);
   digitalWrite (4, HIGH);
   digitalWrite (5, HIGH);
   digitalWrite (6, LOW);
   delay (500);
   digitalWrite (3, HIGH);
   digitalWrite (4, LOW);
   digitalWrite (5, LOW);
   digitalWrite (6, HIGH);
   delay (500);digitalWrite (3, LOW);
   digitalWrite (4, HIGH);
   digitalWrite (5, LOW);
   digitalWrite (6, LOW);
   delay (400);
      digitalWrite(3, HIGH);
    digitalWrite (4, HIGH);
    digitalWrite(5,LOW);
    digitalWrite(6,LOW);
    delay(600);
    digitalWrite (3, LOW);
   digitalWrite (4, HIGH);
   digitalWrite (5, HIGH);
   digitalWrite (6, LOW);
   delay (500);
   digitalWrite (3, HIGH);
   digitalWrite (4, LOW);
   digitalWrite (5, LOW);
   digitalWrite (6, HIGH);
   delay (500);digitalWrite (3, LOW);
   digitalWrite (4, HIGH);
   digitalWrite (5, LOW);
   digitalWrite (6, LOW);
   delay (400);
      digitalWrite(3, HIGH);
    digitalWrite (4, HIGH);
    digitalWrite(5,LOW);
    digitalWrite(6,LOW);
    delay(600);
    digitalWrite (3, LOW);
   digitalWrite (4, HIGH);
   digitalWrite (5, HIGH);
   digitalWrite (6, LOW);
   delay (500);
   digitalWrite (3, HIGH);
   digitalWrite (4, LOW);
   digitalWrite (5, LOW);
   digitalWrite (6, HIGH);
   delay (500);digitalWrite (3, LOW);
   digitalWrite (4, HIGH);
   digitalWrite (5, LOW);
   digitalWrite (6, LOW);
   delay (400);
      digitalWrite(3, HIGH);
    digitalWrite (4, HIGH);
    digitalWrite(5,LOW);
    digitalWrite(6,LOW);
    delay(600);
    digitalWrite (3, LOW);
   digitalWrite (4, HIGH);
   digitalWrite (5, HIGH);
   digitalWrite (6, LOW);
   delay (500);
   digitalWrite (3, HIGH);
   digitalWrite (4, LOW);
   digitalWrite (5, LOW);
   digitalWrite (6, HIGH);
   delay (500);digitalWrite (3, LOW);
   digitalWrite (4, HIGH);
   digitalWrite (5, LOW);
   digitalWrite (6, LOW);
   delay (400);
      digitalWrite(3, HIGH);
    digitalWrite (4, HIGH);
    digitalWrite(5,LOW);
    digitalWrite(6,LOW);
    delay(600);
    digitalWrite (3, LOW);
   digitalWrite (4, HIGH);
   digitalWrite (5, HIGH);
   digitalWrite (6, LOW);
   delay (500);
   digitalWrite (3, HIGH);
   digitalWrite (4, LOW);
   digitalWrite (5, LOW);
   digitalWrite (6, HIGH);
   delay (500);digitalWrite (3, LOW);
   digitalWrite (4, HIGH);
   digitalWrite (5, LOW);
   digitalWrite (6, LOW);
   delay (400);
      digitalWrite(3, HIGH);
    digitalWrite (4, HIGH);
    digitalWrite(5,LOW);
    digitalWrite(6,LOW);
    delay(600);
    digitalWrite (3, LOW);
   digitalWrite (4, HIGH);
   digitalWrite (5, HIGH);
   digitalWrite (6, LOW);
   delay (500);
   digitalWrite (3, HIGH);
   digitalWrite (4, LOW);
   digitalWrite (5, LOW);
   digitalWrite (6, HIGH);
   delay (500);
 }


 readvoice="";}} //Reset the variable