Hello There!

Humans just love to control stuff, don't they? Well I bet you do too! So being quite the Arduino enthusiast myself; Today I will guide you through a project that I have made which I am you will surely enjoy making too! Without further ado, let's dive in!

This will be a Bluetooth controlled car so for this project we will be using the HC-05 Bluetooth module to receive the controlling commands from any smartphone with the Google Play Store.

We will also need an Android app which will be sending the controlling commands to the Bluetooth module(HC-05). I will provide further details in a while.

Materials

1x Arduino Uno
2x DC motors. (Steering motor and Forward/Reverse Motor)
1x L298 Motor Driver Card.
1x Bluetooth Module (HC-05, HC-06 ect.)
1x Battery or Powerbank ( 9- 12 volt) (You can choose this according to your car's power )
4x LEDs
1x Buzzer
2x 1kΩ Resistors
2x 220Ω Resistors
1x On/Off Switch
Wires

Project Application steps:

Install “Arduino Bluetooth Car Control” Application from the link below: https://play.google.com/store/apps/details?id=com.mtm.car22&hl=tr

App Screenshot

Download the connection schematic, installation steps and Arduino .ino code from the link: https://drive.google.com/drive/u/0/folders/0B8lboyisdqhBU0EtdEl3RExGdmc
Connect your devices. (It's explained below.)

Connection Schematic

Download the Arduino .ino code onto your Arduino Uno card.

That's all. (It takes just one hour.)

Enjoy.

(Also you can make some different applications by changing the Arduino .ino code.)

🛠️ Deep Dive / Technical Analysis

Tethering a robot chassis explicitly limits its environmental exploration radius! The Arduino Bluetooth Car severs the wired serial connection permanently, transferring absolute kinematic command arrays to an Android smartphone! By integrating an HC-05 Bluetooth transceiver, the Arduino constantly listens for Serial 1 or 0 command characters traversing the 2.4GHz RF spectrum. When it intercepts a valid command, it aggressively triggers massive physical H-Bridge power drivers to wildly spin two DC gear motors in opposing synchronized matrices!

The L298N H-Bridge Motor Paradigm

An Arduino digital pin outputs an incredibly pathetic 40 milliamps of power. A DC TT-Gear motor demands massive 500-1000 milliamp spikes!

Wiring a motor straight into Pin 3 will instantly blow the Atmega328P silicon die!
You MUST interface the Arduino through an L298N Dual H-Bridge Motor Driver.
The L298N receives massive 9V battery power directly.
The Arduino sends weak 5V Logic signals (IN1, IN2, IN3, IN4) to explicitly instruct the massive H-Bridge which direction to dump the heavy current into the motors!

if (Serial.available() > 0) {
  char command = Serial.read();

  if (command == 'F') { // FORWARD KINEMATICS!
    digitalWrite(IN1, HIGH); // Left Motor Fwd
    digitalWrite(IN2, LOW);
    digitalWrite(IN3, HIGH); // Right Motor Fwd
    digitalWrite(IN4, LOW);
  } 
  else if (command == 'L') { // AGGRESSIVE TANK TURN LEFT!
    digitalWrite(IN1, LOW);  // Left Motor violently reverses!
    digitalWrite(IN2, HIGH); 
    digitalWrite(IN3, HIGH); // Right Motor thrusts forward!
    digitalWrite(IN4, LOW);
  }
}

Creating The Android Tactile Layout

Standard Bluetooth Terminal Apps are boring. The project relies upon absolute visual mapping!

Using MIT App Inventor, you drag physical directional arrows (Up, Down, Left, Right) onto a smartphone canvas.
When you TouchDown on the Up Arrow, the App blasts an 'F' via Bluetooth.
Crucially: When you TouchUp (release the button), the App instantly blasts an 'S' (Stop), causing the Arduino to forcefully kill all L298N pins LOW to physically brake the chassis!

Autonomous Hardware Infrastructure

Arduino Uno Rev3 (Acts as the primary brain mapping RF serial data into pin matrices).
HC-05 or JDY-31 Bluetooth Module (Requires a 3.3V voltage divider resistor pair on its RX pin to prevent Arduino 5V logic from permanently destroying the Bluetooth chip!).
L298N Dual Motor Driver (Capable of routing extreme 2Amp currents natively!).
2x or 4x Yellow TT Gear Motors mounted to an acrylic or 3D-printed chassis.
Dedicated Motor Battery Pack (Do NOT power the motors from the Arduino 5V pin. The L298N requires a dedicated 2-cell 18650 7.4V battery pack wired straight into its input block to prevent processor brownouts!).