Components Required

• Arduino UNO
• HW-130 Motor Driver Shield (L293D based)
• 4 × DC Gear Motors
• Bluetooth Module (HC-05 or HC-06)
• 2 × Rubber Tank Tracks
• Li-ion Battery Pack
• Jumper Wires
• Robot Tank Chassis

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Motor Connections

Your 4 motors will act like a tank drive system:

• Left Side Motors → M1 and M2
• Right Side Motors → M3 and M4

Motor Driver Port	Motor
M1	Left Front Motor
M2	Left Rear Motor
M3	Right Front Motor
M4	Right Rear Motor

Simply connect the motors to the screw terminals on the HW-130 shield.

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Bluetooth Module Connection

Since the shield uses most digital pins, we will use A0 and A1 as SoftwareSerial pins.

Bluetooth Pin	Arduino Pin
VCC	5V
GND	GND
TX	A0
RX	A1

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Power Connection

Motor power should NOT come from Arduino USB.

Recommended:

• Battery + → Motor Shield EXT_PWR
• Battery – → Motor Shield GND

Voltage range:

• 7V – 12V recommended

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Control Commands

The robot will respond to these commands from a Bluetooth App:

Command	Action
F	Move Forward
B	Move Backward
L	Turn Left
R	Turn Right
S	Stop

You can send these commands from apps like:

• Arduino Bluetooth Controller
• Serial Bluetooth Terminal
• Bluetooth RC Controller

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Arduino Code

Install Library first:

AFMotor Library

Open Arduino IDE then follow below steps:
Click Tools → Manage Libraries → Search AFMotor

#include <AFMotor.h>
#include <SoftwareSerial.h>

// Bluetooth RX, TX
SoftwareSerial BT(A0, A1);

// Motors
AF_DCMotor motor1(1); // Left Front
AF_DCMotor motor2(2); // Left Rear
AF_DCMotor motor3(3); // Right Front
AF_DCMotor motor4(4); // Right Rear

char command;

void setup()
{
  Serial.begin(9600);
  BT.begin(9600);

  motor1.setSpeed(225);
  motor2.setSpeed(225);
  motor3.setSpeed(225);
  motor4.setSpeed(225);
}

void loop()
{
  if (BT.available())
  {
    command = BT.read();
    Serial.println(command);

    if (command == 'F')
    {
      forward();
    }
    else if (command == 'B')
    {
      backward();
    }
    else if (command == 'L')
    {
      left();
    }
    else if (command == 'R')
    {
      right();
    }
    else if (command == 'S')
    {
      stopRobot();
    }
  }
}

void forward()
{
  motor1.run(FORWARD);
  motor2.run(FORWARD);

  motor3.run(FORWARD);
  motor4.run(FORWARD);
}

void backward()
{
  motor1.run(BACKWARD);
  motor2.run(BACKWARD);

  motor3.run(BACKWARD);
  motor4.run(BACKWARD);
}

void left()
{
  motor1.run(BACKWARD);
  motor2.run(BACKWARD);

  motor3.run(FORWARD);
  motor4.run(FORWARD);
}

void right()
{
  motor1.run(FORWARD);
  motor2.run(FORWARD);

  motor3.run(BACKWARD);
  motor4.run(BACKWARD);
}

void stopRobot()
{
  motor1.run(RELEASE);
  motor2.run(RELEASE);
  motor3.run(RELEASE);
  motor4.run(RELEASE);
}

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Please Note: Pair HC-05 with phone Bluetooth first. Then Connect HC-05 with Bluetooth RC Controller APP.