Motor with Wires
Motor with Wires
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How to Program a Remote Control Toy Car with Arduino: A Beginner’s Guide

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Have you ever wondered how those cool remote control toy cars work? Many people think that electronics and programming are complicated and intimidating, requiring years of study. However, that’s a common misconception! As someone passionate about technology, mechanics, and coding, diving into Arduino projects has been incredibly rewarding. If you’re curious about electronics and enjoy hands-on projects, building an Arduino-powered RC car is a fantastic way to start. Like many, I had fond memories of RC cars from childhood and wanted to revisit that fun with my newfound coding skills and an Arduino kit.

This guide will walk you through creating your own Arduino-based remote control car from scratch. No prior experience in programming, Arduino, or electronics is necessary. While some background in these areas might be helpful, these instructions are designed for beginners. You might be wondering about the power source – we’ll be using a power bank! Power banks are increasingly affordable, often cheaper than traditional batteries, and many of us already have them at home. They are rechargeable and reusable, making them a convenient and eco-friendly option. This project focuses on the fundamental principles of building an RC car using readily available materials and provides a detailed explanation of the code. The skills you learn here can also be applied to various other exciting projects, so let’s get started on building and learning How To Program A Remote Control Toy Car!

As a hobbyist, I aimed to use common household items and avoid specialized tools like soldering irons as much as possible. We’ll repurpose components like USB cables and power banks, items many of you likely have lying around. Feel free to follow these instructions closely or get creative and adapt them to your own resources and ideas. Here’s a list of the materials you’ll need to gather:

  • Arduino UNO
  • Car chassis kit (including wheels and motors)
  • Male-male and female-male jumper wires
  • Electrical insulation tape
  • Bluetooth module (HC-06 or HC-05)
  • DC motor controller (L298N)
  • Power Bank with 2 USB outputs
  • Piezo buzzer
  • Android mobile phone
  • PC with Arduino IDE installed
  • ArduCar – Arduino RC Car Bluetooth Controller App

Step 1: Assembling the Chassis

The first step in learning how to program a remote control toy car is to actually build the car! We’ll begin by assembling the chassis. If you purchased a kit, it likely includes assembly instructions. However, here’s a step-by-step guide to help you through the process:

  1. Gather the main chassis frame, four small plastic motor brackets (two per motor), screws, brass spacers, nuts, motors, a spare USB cable, and four jumper wires.
  2. Connect a jumper wire to each terminal of both motors. Soldering provides a more secure connection, but if you don’t have a soldering iron, simply twisting the wire around each terminal will work for this project.

  1. Take your old USB cable and cut off one end, leaving about 20cm (approximately 8 inches) of cable with the USB connector.
  2. Carefully strip a few centimeters of the outer cable insulation to expose the internal wires. You should find 4 or 5 wires inside; we are interested in the black (GND – Ground) and red (Plus – Power) wires. Strip about 2-4cm of insulation from the ends of the red and black wires. You can leave them as they are, or for a stronger connection, twist or solder them to longer, more robust jumper wires. This will ensure a reliable power connection for your RC car.

Image: A section of a USB cable is shown with the outer insulation stripped away, revealing red and black power wires.

  1. Mount the motors to the chassis frame using the plastic brackets, screws, and nuts. Pay attention to the small dot on one side of each motor. These dots should face inwards, towards each other, when both motors are mounted on the chassis. This orientation is important for the motors to rotate in the correct directions for forward and backward movement.

  1. Now, for the third supporting nylon wheel. Locate the four small holes arranged in a square pattern at the end of the chassis frame. Attach the brass spacers to these holes using screws, ensuring the spacers are on the same side of the frame as the motors.
  2. Mount the nylon supporting wheel onto the brass spacers using screws. This wheel will provide stability to your RC car.

  1. Install the driving wheels onto each motor shaft. Note the specific shape inside the wheel hub, ensuring it aligns correctly with the motor shaft. You might encounter some resistance while pushing the wheels onto the shafts, so apply gentle but firm pressure to secure them.
  2. At this point, you can mount the Arduino UNO board and the L298N DC motor controller onto the chassis frame. Use spare screws and nuts from your kit. Secure any exposed wires with electrical insulation tape to prevent shorts and ensure a clean setup.

Step 2: Wiring the Electronics

With the chassis assembled and the boards mounted, the next crucial step in how to program a remote control toy car is wiring the electronic components. Prepare your male-male and female-male jumper wires.

  1. Connect the motor wires to the L298N DC motor controller. The lower pins (closer to the ground) are considered positive (+), and the upper pins (closer to the frame) are negative or Ground (GND). Follow this wiring configuration:

    • OUT1: Left motor (-) GND wire
    • OUT2: Left motor (+) wire
    • OUT3: Right motor (+) wire
    • OUT4: Right motor (-) GND wire

  1. Now, connect the Arduino UNO to the DC motor controller. Use the IN1, IN2, IN3, and IN4 pins on the motor controller to send control signals from the Arduino. The OUT pins power the motors, while the IN pins receive commands. You might need female-male jumper wires for these connections. If you only have male-male wires, you can carefully modify them or solder wires to ensure a secure connection.

    • IN1: Arduino Digital Pin 5
    • IN2: Arduino Digital Pin 6
    • IN3: Arduino Digital Pin 10
    • IN4: Arduino Digital Pin 11

  2. Connect the Bluetooth module. The Bluetooth module (HC-06 or HC-05) enables wireless control of your RC car. It typically has four pins labeled VCC (Power), GND (Ground), TXD (Transmit Data), and RXD (Receive Data). Female-male jumper wires are likely needed here as well.

    • VCC: Arduino 5V pin
    • GND: Arduino GND pin
    • TXD: Arduino Digital Pin 0 (RXD)
    • RXD: Arduino Digital Pin 1 (TXD)

    Note that the TXD and RXD pins are cross-connected. The Bluetooth module’s TXD (transmit) pin connects to the Arduino’s RXD (receive) pin, and vice versa. This allows data to be transmitted and received correctly between the devices.

  1. Connect the Piezo buzzer. The piezo buzzer will add fun sound effects to your RC car. It has two legs: a longer leg (Anode +) and a shorter leg (Cathode -). While a 330 Ohm resistor is recommended between the Anode and the Arduino to protect the buzzer, it’s often omitted to increase volume, especially with smaller buzzers. However, be aware that omitting the resistor might shorten the buzzer’s lifespan. Female-male jumper wires may again be helpful.

    • Anode (+) (long leg): Arduino Digital Pin 3
    • Cathode (-) (short leg): Arduino GND pin

  1. Powering the circuit. Use the prepared USB cable (from Step 1) to power both the Arduino UNO and the L298N motor controller. Connect the red (+) and black (-) wires from the USB cable to the motor controller’s power input.

    • Red wire (+): L298N 12V input
    • Black wire (-): L298N GND input

  2. Final power connections. Connect two USB cables to your power bank. Plug one USB cable into the Arduino UNO to power the microcontroller. Plug the other USB cable (connected to the motor controller in the previous step) into the power bank as well. Mount the power bank onto the chassis using electrical tape or another secure method. Some power banks have a power button, so ensure it’s switched on to power the circuit.

  1. With all components wired, we’re ready to program the remote control toy car!

Step 3: Programming Your Arduino RC Car

Now for the exciting part: programming your remote control toy car! This step involves uploading code to the Arduino board and installing a control application on your Android phone. You’ll need the Arduino IDE (Integrated Development Environment) software installed on your computer, which can be downloaded from the official Arduino website.

Once installed, configure the Arduino IDE:

  1. Open the Arduino IDE. Go to “Tools” in the menu bar.
  2. Hover over “Board:” and select “Arduino Uno” (or whichever Arduino board you are using).
  3. Next, go to “Port:”. Connect your Arduino UNO to your computer using a USB cable. The “Port:” option should become active. Select the appropriate COM port that your Arduino is connected to (e.g., COM5, /dev/ttyACM0). If you’re unsure, try different USB ports on your computer until the Arduino is recognized.

Before uploading the code:

  1. You can either download the provided Arduino code file, open it in the Arduino IDE, and upload it directly.
  2. Or, create a new sketch in the Arduino IDE (File > New), copy and paste the code provided below into the sketch, and then click the “Upload” button (the right-arrow icon).

Important Note: Disconnect the Bluetooth module’s TX (Digital 1) and RX (Digital 0) wires from the Arduino before uploading the code. These pins are used for communication with your computer during code upload. Leaving the Bluetooth module connected can interfere with the upload process and may cause the Arduino IDE to freeze at the “uploading” stage. Reconnect the Bluetooth module after the code upload is complete.

Here’s the Arduino code you’ll need to upload:

#define in1 5
#define in2 6
#define in3 10
#define in4 11
int state;
int piezo = 3;

void setup() {
  pinMode(in1, OUTPUT);
  pinMode(in2, OUTPUT);
  pinMode(in3, OUTPUT);
  pinMode(in4, OUTPUT);
  pinMode(piezo,OUTPUT);
  Serial.begin(9600);
}

void loop() {
  if (Serial.available() > 0) {
    state = Serial.read();
    Stop();
    switch (state) {
      case 'F': forward(); soundFX(3000.0,30+400*(1+sin(millis()/5000))); break;
      case 'G': forwardleft(); soundFX(3000.0,60); break;
      case 'D': forwardright(); soundFX(3000.0,60); break;
      case 'N': backright(); soundFX(3000.0,30+100*(1+sin(millis()/2500))); break;
      case 'C': backleft(); soundFX(3000.0,30+100*(1+sin(millis()/2500))); soundFX(3000.0,30+100*(1+sin(millis()/2500))); soundFX(3000.0,30+100*(1+sin(millis()/2500))); soundFX(3000.0,30+100*(1+sin(millis()/2500))); break;
      case 'B': back(); soundFX(3000.0,30+200*(1+sin(millis()/2500))); soundFX(3000.0,30+200*(1+sin(millis()/2500))); soundFX(3000.0,30+200*(1+sin(millis()/2500))); soundFX(3000.0,30+200*(1+sin(millis()/2500))); break;
      case 'L': left(); soundFX(3000.0,60); soundFX(3000.0,60); soundFX(3000.0,60); soundFX(3000.0,60); break;
      case 'R': right(); soundFX(3000.0,60); soundFX(3000.0,60); soundFX(3000.0,60); soundFX(3000.0,60); break;
      case 'H': soundFX(3000.0,30+200*(1+sin(millis()/2500))); soundFX(3000.0,60); soundFX(3000.0,30+200*(1+sin(millis()/2500))); soundFX(3000.0,60); break;
    }
  }
}

void forward() {
  analogWrite(in1, 255);
  analogWrite(in3, 255);
}

void forwardleft() {
  analogWrite(in1, 50);
  analogWrite(in3, 255);
}

void forwardright() {
  analogWrite(in1, 255);
  analogWrite(in3, 50);
}

void back() {
  analogWrite(in2, 255);
  analogWrite(in4, 255);
}

void backright() {
  analogWrite(in2, 50);
  analogWrite(in4, 255);
}

void backleft() {
  analogWrite(in2, 255);
  analogWrite(in4, 50);
}

void left() {
  analogWrite(in4, 255);
  analogWrite(in1, 255);
}

void right() {
  analogWrite(in3, 255);
  analogWrite(in2, 255);
}

void Stop() {
  analogWrite(in1, 0);
  analogWrite(in2, 0);
  analogWrite(in3, 0);
  analogWrite(in4, 0);
}

void soundFX(float amplitude,float period){
  int uDelay=2+amplitude+amplitude*sin(millis()/period);
  for(int i=0;i<200;i++){
    digitalWrite(piezo, HIGH);
    delayMicroseconds(uDelay);
    digitalWrite(piezo, LOW);
    delayMicroseconds(uDelay);
  }
}

After uploading the code:

  1. Reconnect the Bluetooth module’s TX (Digital 1) and RX (Digital 0) wires to the Arduino.
  2. Reconnect the USB cable (Arduino – Power bank) to the power bank to power up the RC car.

Finally, to control your RC car:

  1. Download and install the “ArduCar – Arduino RC Car Bluetooth Controller” app from the Google Play Store on your Android phone.
  2. Launch the app, connect to your Bluetooth module, and start driving your newly programmed remote control toy car!

You can also explore other similar Bluetooth RC car control apps that send compatible serial commands, or even develop your own custom mobile application for enhanced control and features.

Congratulations! You’ve successfully built and programmed your own Arduino-powered remote control toy car. Have fun experimenting and driving! If you have any questions or suggestions, feel free to leave a comment below.

Step 4: Understanding the Arduino Code and Bluetooth Configuration (Optional)

For those interested in diving deeper into how to program a remote control toy car, let’s explore the Arduino code and Bluetooth module configuration in more detail. Understanding the code will empower you to customize and expand upon this project.

The Arduino code is written in a simplified version of C/C++. Even if you’re new to programming, the structure is relatively straightforward. Arduino programs consist of two main functions: setup() and loop().

1. void setup() { }:

This function runs only once when the Arduino board starts. It’s used to initialize settings and configurations. In our code:

void setup() {
  pinMode(in1, OUTPUT);
  pinMode(in2, OUTPUT);
  pinMode(in3, OUTPUT);
  pinMode(in4, OUTPUT);
  pinMode(piezo,OUTPUT);
  Serial.begin(9600);
}
  • pinMode(in1, OUTPUT); and similar lines configure the Arduino pins connected to the motor controller (in1, in2, in3, in4) and the piezo buzzer (piezo) as OUTPUT pins. This means the Arduino will send signals out through these pins to control these components. INPUT would be used if a pin was receiving data (e.g., from a sensor).
  • Serial.begin(9600); initializes serial communication at a baud rate of 9600 bits per second. This sets up the communication channel through which the Arduino will receive commands from the Bluetooth module. 9600 is a common and stable baud rate for Bluetooth communication.

2. void loop() { }:

The loop() function runs continuously after the setup() function completes. This is where the main program logic resides, constantly checking for commands and controlling the RC car.

void loop() {
  if (Serial.available() > 0) {
    state = Serial.read();
    Stop();
    switch (state) {
      // ... (cases for different commands) ...
    }
  }
}
  • if (Serial.available() > 0): This line checks if there is any data available to be read from the serial port (i.e., from the Bluetooth module). If data is available, the code inside the curly braces {} will be executed.
  • state = Serial.read();: Reads the incoming data from the serial port and stores it in the state variable. This data represents the command sent from your Android app via Bluetooth.
  • Stop();: Calls the Stop() function (defined later in the code) to immediately stop the car’s motors before executing a new command. This ensures smooth transitions between commands.
  • switch (state): A switch statement is used to execute different actions based on the value of the state variable (the command received). Each case represents a different command character sent from the app:
    • case 'F': forward(); soundFX(...); break;: If the received character is ‘F’ (for forward), it calls the forward() function to move the car forward and the soundFX() function to play a sound effect. break; exits the switch statement after executing the corresponding case.
    • Similar case statements exist for other commands like ‘G’ (forward-left), ‘D’ (forward-right), ‘B’ (backward), ‘L’ (left), ‘R’ (right), ‘H’ (honk/sound effect), and others, each calling corresponding movement functions and sound effects.

3. Pin and Variable Definitions:

Before setup(), we define names for the Arduino pins we’re using:

#define in1 5
#define in2 6
#define in3 10
#define in4 11
int state;
int piezo = 3;
  • #define in1 5: The #define directive creates a symbolic constant. Here, in1 is defined as a synonym for the number 5. So, whenever you use in1 in your code, the Arduino IDE will replace it with 5. This makes the code more readable and easier to understand. Similar #define lines are used for in2, in3, and in4, associating them with Arduino pins 6, 10, and 11 respectively. These correspond to the input pins on the L298N motor controller.
  • int state;: Declares an integer variable named state. This variable will store the command character received from the Bluetooth module.
  • int piezo = 3;: Declares an integer variable named piezo and initializes it to 3. This associates the name piezo with Arduino digital pin 3, which is connected to the piezo buzzer.

4. Movement Functions:

Functions like forward(), back(), left(), right(), forwardleft(), forwardright(), backleft(), backright(), and Stop() are defined to control the motors:

void forward() {
  analogWrite(in1, 255);
  analogWrite(in3, 255);
}

void Stop() {
  analogWrite(in1, 0);
  analogWrite(in2, 0);
  analogWrite(in3, 0);
  analogWrite(in4, 0);
}
// ... (other movement functions) ...
  • void forward(): Sets both left and right motors to move forward at full speed. analogWrite(pin, value) is used to control the speed of the motors. analogWrite() sends a PWM (Pulse Width Modulation) signal to the specified pin. The value ranges from 0 to 255, where 0 is off (0% speed) and 255 is full speed (100% speed). By setting analogWrite(in1, 255) and analogWrite(in3, 255), we are instructing the motor controller to drive both motors forward at full speed.
  • void Stop(): Sets all motor control pins to 0, effectively stopping both motors.

5. soundFX() Function:

void soundFX(float amplitude,float period){
  int uDelay=2+amplitude+amplitude*sin(millis()/period);
  for(int i=0;i<200;i++){
    digitalWrite(piezo, HIGH);
    delayMicroseconds(uDelay);
    digitalWrite(piezo, LOW);
    delayMicroseconds(uDelay);
  }
}
  • void soundFX(float amplitude, float period): This function generates a sound effect using the piezo buzzer. It takes amplitude and period as parameters to control the characteristics of the sound. This code is adapted from Arduino forum examples for generating SciFi-like sounds.
  • digitalWrite(piezo, HIGH); and digitalWrite(piezo, LOW);: These lines rapidly switch the piezo buzzer pin HIGH and LOW, creating sound waves. delayMicroseconds(uDelay) controls the duration of the HIGH and LOW pulses, influencing the pitch and tone of the sound. The for loop repeats this process to create a continuous sound.

Bluetooth Module Configuration (Optional):

HC-05 and HC-06 Bluetooth modules typically come pre-configured with default settings like baud rate, name, and password. For basic use, these defaults are often sufficient. However, if you want to customize these settings, you can configure the Bluetooth module using Arduino commands. This usually involves connecting the Bluetooth module to the Arduino in a specific configuration and uploading configuration code. Be cautious when configuring Bluetooth modules, especially regarding voltage levels, as they often operate at 3.3V logic levels, while Arduino UNO operates at 5V. Level shifters or resistors might be needed for safe communication during configuration. Numerous online tutorials detail the Bluetooth module configuration process if you wish to explore this further.

We hope this detailed explanation helps you understand how to program a remote control toy car and encourages you to further explore the world of Arduino and DIY electronics projects! Don’t hesitate to share your own projects and modifications in the comments below.

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