YouTube Video for this RC car

Introduction

In today's world, electronic waste (e-waste) is increasing rapidly, but instead of letting it go to waste, why not repurpose and rebuild something amazing? In this project, I took an old, non-working RC car from an e-waste shop and restored it completely from scratch. My goal was to convert it into a Bluetooth-controlled RC car using Arduino, a Bluetooth module, a 4-channel relay, and a battery.
In this blog, I'll walk you through the entire process—from sourcing the RC car chassis to rewiring and coding it for smooth operation. Let’s get started!

Materials Required

Here are the components I used to restore and upgrade my RC car:

✅ Old RC Car Chassis – Taken from an e-waste shop
✅ Arduino Uno/Nano – Acts as the brain of the RC car
✅ HC-05 Bluetooth Module – For wireless control via a smartphone
✅ 4-Channel Relay Module – To control the motors
✅ 12V Battery (Lithium-ion / Lead-acid) – Power source for the motor
✅ Jumper Wires & Soldering Kit – For connections
✅ Smartphone with Bluetooth Controller App – To control the RC

Step 1: Finding the Right RC Car from E-Waste

The first step in restoring an RC car is to find a suitable chassis. I went to a local e-waste shop and found an old, broken RC car.

The chassis was intact, but the electronics were completely dead.
The DC motors and gears were still in usable condition.
The steering mechanism was functional but needed rewiring.

Once I brought it home, I removed all the unnecessary wires and circuits, keeping only the chassis, wheels, and motors.

Step 2: Connecting the Hardware Components

Now that we have the chassis, let's start wiring the new electronic components. Below is the block diagram of the setup:

Block Diagram

🚗 Arduino → Controls the relay module
🔄 Relay Module → Controls the DC motor movement
📶 Bluetooth Module → Receives commands from a smartphone
🔋 Battery → Powers the system

Here’s a simple block diagram for the wiring:


           Bluetooth Module (HC-05)
                  │
                  │
                  ▼
              Arduino
                  │
    ┌────────────┴────────────┐
    │                         │
  Relay 1                  Relay 2
    │                         │
  Motor 1                   Motor 2

Wiring Connections

Here’s how you should connect everything:

HC-05 Bluetooth Module → Arduino

VCC → 5V (Arduino)
GND → GND (Arduino)
TX → RX (Arduino)
RX → TX (Arduino)

Relay Module → Arduino

IN1 → Pin 4 (Forward)
IN2 → Pin 5 (Backward)
IN3 → Pin 6 (Left)
IN4 → Pin 7 (Right)

Power Supply

Battery (+) → Motor Driver (VCC)
Battery (-) → Arduino GND & Motor Driver GND

Step 3: Uploading the Arduino Code

Here’s the Arduino code that allows the car to be controlled via Bluetooth:

#include <SoftwareSerial.h>

SoftwareSerial BTSerial(2, 3); // Bluetooth RX, TX

#define relay1 4  // Forward
#define relay2 5  // Backward
#define relay3 6  // Left
#define relay4 7  // Right

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

  pinMode(relay1, OUTPUT);
  pinMode(relay2, OUTPUT);
  pinMode(relay3, OUTPUT);
  pinMode(relay4, OUTPUT);
}

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

    if (command == 'F') { // Move Forward
      digitalWrite(relay1, HIGH);
      digitalWrite(relay2, LOW);
    } else if (command == 'B') { // Move Backward
      digitalWrite(relay1, LOW);
      digitalWrite(relay2, HIGH);
    } else if (command == 'L') { // Turn Left
      digitalWrite(relay3, HIGH);
      digitalWrite(relay4, LOW);
    } else if (command == 'R') { // Turn Right
      digitalWrite(relay3, LOW);
      digitalWrite(relay4, HIGH);
    } else if (command == 'S') { // Stop
      digitalWrite(relay1, LOW);
      digitalWrite(relay2, LOW);
      digitalWrite(relay3, LOW);
      digitalWrite(relay4, LOW);
    }
  }
}

Step 4: Controlling the RC Car via Smartphone

Now that the hardware and code are ready, let’s control the car using a Bluetooth app.

Steps to Connect Your Phone to the Car:

Download any Bluetooth Controller App (like "Arduino Bluetooth Controller").
Pair your HC-05 module with your smartphone (Default PIN: 1234 or 0000).
Open the app and set up the commands:
- F → Forward
- B → Backward
- L → Left
- R → Right
- S → Stop
Start driving your RC car wirelessly! 🚗💨

Final Thoughts: My Experience & Challenges

✨ Building this RC car from e-waste was an exciting experience!

The biggest challenge was finding a functional motor and chassis, but with a little effort, I managed to get it running.
The relay-based motor control worked fine, but for smoother movement, a motor driver (L298N) could be a better alternative.
The battery life was decent, but upgrading to a Li-Po battery would improve performance.

This project is a great way to learn about electronics, recycling, and automation. If you have an old RC car lying around, don’t throw it away—restore it! 🚀

Conclusion

This DIY Bluetooth-controlled RC car from e-waste is a fun and practical project for electronics and robotics enthusiasts. If you enjoyed this tutorial, share it with your friends, and let me know if you have any questions in the comments below.

RC car link: https://amzn.to/4kR35Qv , https://amzn.to/4hvWxnt

Arduino Uno: https://amzn.to/3XMaDu0

Bluetooth module:https://amzn.to/4bRFOtz

4 Channel relay module: https://amzn.to/3DIzSXp

Lithium ion battery:https://amzn.to/3DGbLIM

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Thursday, 13 March 2025

Restoring an RC Car from E-Waste – DIY Bluetooth-Controlled RC Car Using Arduino