HACK-AF-MOTOR-SHIELD
Robotic Car

Arduino Nano & Bluetooth Robotics Platform | NextGenRoboticX

In this project, we will explain how to design and develop a Bluetooth-controlled robot using the HACK-AF-MOTOR-SHIELD—an Arduino Nano-friendly, ready-to-use robotics development platform. Since this board is pin-compatible with the classical Adafruit Motor Shield, users can leverage Adafruit's high-performance library functions directly.

To establish wireless control, we'll interface an HC-05 Bluetooth Transceiver directly with the shield's onboard header and use a smartphone Voice/Command Android app to steer the robotic car remotely.

Robotic Car with Hack-AF Motor Shield

Figure 1: Fully Configured Robotic Car Platform

Project Demonstration Video

Hardware Requirements

Core Component Details

1. HACK-AF-MOTOR-SHIELD Board

HACK-AF-MOTOR-SHIELD is an Arduino Nano-friendly, ready-to-use robotics platform. It is fully pin-compatible with the classic Adafruit motor shield, meaning you can directly deploy Adafruit's libraries. Using just three digital pins on the Arduino Nano, it can drive 2 hobby servos, 4 bi-directional DC gear motors, or two 4-wire stepper motors.

Crucially, the board includes a dedicated onboard slot to mount the HC-05/HC-06 Bluetooth module directly, eliminating messy breadboard connections.

HACK-AF-MOTOR-SHIELD Board

Figure 2: HACK-AF-MOTOR-SHIELD Robotics Board

HACK-AF Shield Features

2. Arduino Nano Microcontroller

The Arduino Nano is a small, complete, and breadboard-friendly microcontroller board based on the ATmega328P. It shares almost identical processing capability with the larger Arduino Uno but is condensed into a highly compact form factor, operating with a Mini-B USB cable.

Arduino Nano Board

Figure 3: Arduino Nano Microcontroller

Arduino Nano Specifications

3. HC-05 Bluetooth Serial Module

The HC-05 serial module is designed for wireless serial connection setups. It uses a base 2.4GHz radio transceiver implementing EDR (Enhanced Data Rate) up to 3Mbps, making it a robust master/slave communications link.

HC-05 Specifications

4. BO Gear Motor with Plastic Tire Wheel

Standard high-torque Battery Operated DC gear motors with a built-in 48:1 reduction ratio to provide optimal traction and speeds between 20 to 48 meters per minute.

DC BO Gear Motor

Figure 4: Geared BO Motor and Wheel

5. Stable Robotic Chassis

A multi-tier chassis layout providing ample space to cleanly secure the HACK-AF shield, rechargeable batteries, and gear motors.

Robotic Chassis Layout

Figure 5: High-grade Dual-Tier Robotic Chassis

Circuit Connections

Secure the Arduino Nano directly into the center headers of the HACK-AF-MOTOR-SHIELD. Insert the HC-05 Bluetooth module into the pre-routed 4-pin female headers. Connect the DC motors to terminal block outputs M1, M2, M3, and M4. Insert a 7.4V - 9V battery pack to the external power terminals of the shield.

HACK-AF Hookup Schematic

Figure 6: Complete Platform Schematic Diagram

Arduino Source Code

Use the following code block to program your Arduino Nano. Ensure that the HC-05 module is temporarily unplugged while uploading code to avoid serial programming port conflicts.

// Voice & Bluetooth Controlled Robotic Car using HACK-AF-MOTOR-SHIELD - NextGenRoboticX
#include <AFMotor.h>

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

char commandVal;

void setup() {
  Serial.begin(9600); // Bluetooth Serial Communication (HC-05 onboard slot)
  
  // Set initial motor speed
  motor1.setSpeed(200);
  motor2.setSpeed(200);
  motor3.setSpeed(200);
  motor4.setSpeed(200);
}

void loop() {
  if (Serial.available() > 0) {
    commandVal = Serial.read();
    stopRobot(); // Always stop first before executing next command
    
    switch (commandVal) {
      case 'F':
        moveForward();
        break;
      case 'B':
        moveBackward();
        break;
      case 'L':
        turnLeft();
        break;
      case 'R':
        turnRight();
        break;
      case 'S':
        stopRobot();
        break;
    }
  }
}

void moveForward() {
  motor1.run(FORWARD);
  motor2.run(FORWARD);
  motor3.run(FORWARD);
  motor4.run(FORWARD);
}

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

void turnLeft() {
  motor1.run(BACKWARD);
  motor2.run(BACKWARD);
  motor3.run(FORWARD);
  motor4.run(FORWARD);
}

void turnRight() {
  motor1.run(FORWARD);
  motor2.run(FORWARD);
  motor3.run(BACKWARD);
  motor4.run(BACKWARD);
}

void moveBackward() {
  motor1.run(BACKWARD);
  motor2.run(BACKWARD);
  motor3.run(BACKWARD);
  motor4.run(BACKWARD);
}

Limitations & Applications

Limitations

Applications

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