Published November 19, 2017 © GPL3+

FPV RC Car

Control an RC car with a computer racing wheel and in the end add a wireless camera.

IntermediateFull instructions provided8 hours3,546

Things used in this project

Hardware components

RC Auto

Wireless Camera

DFRobot Dreamer Nano V4.1

Computador Racing Wheel

L298N

nRF24L01+

7.4V 800mA LiPo

Resistor 10k ohm

100K Resistor

Software apps and online services

Arduino IDE

Hand tools and fabrication machines

Dremel

Story

CThis project had been in my drawer for some time and since the Maker Fair's coming to town, this was a good time to make it.

A long time ago, there was a game called "Micro Machines" for Sega Mega Drive (Genesis) that I spent hours playing. Basically this was a racing game with small cars where the race track was parts of daily life objects. I found that there is a new version of this old classic.

On the original version, the game had top view of the track and cars, but I wanted to have the first person view in a head display. The camera would move according to the movement of the head of the player.

The controller should be a racing wheel. Unfortunately, this was not possible and, in the end, this was what I got.

Due to several factors, I did not implemented the head display and servo-controlled camera but the car is controller by the racing wheel, I have a wireless camera and everything works. The problem is the range. I can only control and see camera feed if every transmitter and receiver units are in line of sight.

In any case there are very interesting aspects of this project worth sharing.

Components

1 / 5

RC Car

I just selected the cheapest that I could find in a 1:20 scale.

Wireless Camera

I had several choices here but I probably went with the worst one. If you are planning on doing something like this, DO NOT use these type of cameras.

Microcontroller

DFRobot Dreamer Nano V4.1, the 2.54mm pinout is essencial for this project. Check DFRobot wiki page for more info regarding this microcontroller.

Computer Racing Wheel

Today it is very easy to find old racing controllers almost for free. This one I got for free in the local internet market.

It comes with the old 15 pins game port, that connects with the sound card of the computer.

Motor Controller

The choice was the L298N with a capability of 2A and with a max of 46V in the input which serves perfectly for this project.

RF transceiver

For the wireless communication between the racing wheel and car, I went with the nRF24L01+ RF transceiver.

I already had some here, and they are easy to use.

Battery

A 7.4V 800mA LiPo battery provides the power to the RC car, microcontroller, RF transceiver, and wireless camera

Miscellaneous

4x - 10K Resistor

4x - 100K Resistor

Perfboard (a usual in my projects)

9V battery plug

some wires

Connect the Components

Computar Racing Wheel Transmitter

The game port pin out can be find here: https://en.wikipedia.org/wiki/Game_por

I also found a very nice site with a schematic for the connection to the Arduino: http://www.built-to-spec.com/blog/2009/09/10/using-a-pc-joystick-with-the-arduino/

The circuit is built on the prefboard according to the schematic that I've added.

For the NRF24L01+ connection I'm using the base adapter that bring a 3.3V voltage regulator plus additional capacitors for increasing the line stabilization.

If you want just to use the NRF24L01+, the power line need to come from the +3.3V from the Arduino.

Transmitter

RC Car Receiver

For the car, I also use the NRF24L01+ base adapter - again, this is optional.

The L298n connects to pins D2 to D7.

The power for a wireless camera also comes from the battery pack.

After some tests, I used the rule of thumb for the heat sink and decided to use a fan.

Code

For the code to run, you will need to install the RF24 library.

You can download it here: https://github.com/nRF24/RF24.

Pins D9 and D10 are used also for this library, so do not forget to change them if you want to use other ones.

RF24 radio(9, 10); //Set up nRF24L01+ radio on SPI bus plus pins 9 and 10

Then declare the pins for the controller in the Car_TX code.

//Declare the pins for the racing wheel 
const int wheel_direction = A0;
const int button_1A = 2;
const int Button_2A = 4;
const int button_1B = 3;
const int button_2B = 5;

And the pins for the motor controller drive

//Define Pins for Motor Drive 
//Motor Speed
int enable_A = 3;
int in1Pin = 2;
int in2Pin = 4;
//Motor Direction
int enable_B = 5;
int in3Pin = 6;
int in4Pin = 7;

Live Feed

The wireless camera set consists of a wireless camera and a receiver capable of outputting a composed video signal. The receiver is then connected to a converter that allows a connection to VGA monitors.

Functional Test

Test Run

Conclusion

After finishing everything and assembling it, the result was not the one expected. The range of everything was about 2m indoors! Probably because this was done with a budget of around 50€!!

This one needs a complete rethinking on the components selected. I will probably use, in the future, the same cameras and transmitters used in the drones with FPV. Today it is already possible to get some equipment without breaking the bank.

Not everything was bad. During the tests, it was very fun to drive the car with the racing controller. I will probably build a new version using small RC car but with a racing wheel controller.

Feel free to comment or send me a message if you found any mistakes, or if you have any suggestions/improvements or questions.

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Code

#include <SPI.h>
#include "nRF24L01.h"
#include "RF24.h"

RF24 radio(9, 10); //Set up nRF24L01+ radio on SPI bus plus pins 9 and 10

const uint64_t pipes[2] = { 0xF0F0F0F0E1LL, 0xF0F0F0F0D2LL };//2 pipes communication
unsigned int received_data[3];
unsigned int num_received_data = sizeof(received_data);


////////////////////////////////////////////////////////////////////////////////////

//Define Pins for Motor Drive
//Motor Speed
int enable_A = 3;
int in1Pin = 2;
int in2Pin = 4;

//Motor Direction
int enable_B = 5;
int in3Pin = 6;
int in4Pin = 7;

boolean reverse = false;
int motor_pwm = 0;
boolean right = false;
boolean left = false;


////////////////////////////////////////////////////////////////////////////////////
void setup(void)
{
  Serial.begin(115200);
  //configure pin modes

  pinMode(in1Pin, OUTPUT);
  pinMode(in2Pin, OUTPUT);
  pinMode(enable_A, OUTPUT);

  pinMode(in3Pin, OUTPUT);
  pinMode(in4Pin, OUTPUT);
  pinMode(enable_B, OUTPUT);

  radio.begin();


  radio.setPALevel( RF24_PA_MAX ) ; // Max power
  radio.setDataRate( RF24_250KBPS ) ; // Min speed (for better range I presume)
  radio.setCRCLength( RF24_CRC_8 ) ; // 8 bits CRC
  radio.setChannel(108); //2.508 Ghz - Above most Wifi Channel
  radio.setRetries(15, 15); // increase the delay between retries & # of retries
  radio.openReadingPipe(1, pipes[1]);
  radio.startListening();
  radio.printDetails();
  radio.openWritingPipe(pipes[1]);
  radio.openReadingPipe(1, pipes[0]);
  radio.startListening();
}//void setup

void loop(void)
{

  ///////////////////////////////Radio reading///////////////////////////////////////////////////////
  if ( radio.available() )
  {
    bool done = false;
    while (!done)
    {
      radio.read(&received_data, num_received_data);
      done = true;
      delay(30);
    }// while (!done)

    Serial.print(received_data[0]);
    Serial.print ("---");
    Serial.print(received_data[1]);
    Serial.print ("---");

    Serial.println(received_data[2]);



    if (received_data[0] < 0 || received_data[0] != 1)

      if (received_data [1] == 1 && received_data [2] == 0)
      {

        motor_pwm = motor_pwm + 10;
        reverse = false;

      }
      else if (received_data [2] == 1 && received_data [1] == 0)
      {

        // if (reverse==false) motor_pwm=0;

        motor_pwm = motor_pwm + 10;
        reverse = true;

      }
      else  motor_pwm = motor_pwm - 10;


    motor_pwm = constrain(motor_pwm, 0, 200);

    if (received_data [0] <= 90 && received_data [0] >= 40)
    {
      analogWrite(enable_B, 0);
      digitalWrite(in3Pin, 0);
      digitalWrite(in4Pin, 0);
    }
    if (received_data [0] >= 75 &&  received_data [0] <= 90) //Left
    {

      analogWrite(enable_B, 230);
      digitalWrite(in3Pin, 0);
      digitalWrite(in4Pin, 1);

    } else if (received_data [0] >= 40 && received_data [0] <= 58) //Right
    {
      analogWrite(enable_B, 230);
      digitalWrite(in3Pin, 1);
      digitalWrite(in4Pin, 0);
    }

  }//if ( radio.available() )


  setMotor(motor_pwm, reverse);

}// void loop


void setMotor(int speed, boolean reverse)
{
  analogWrite(enable_A, speed);
  digitalWrite(in1Pin, ! reverse);
  digitalWrite(in2Pin, reverse);
}


void Car_direction(int speed, boolean direction)
{

}

#include <SPI.h>
#include "nRF24L01.h"
#include "RF24.h"

RF24 radio(9, 10); //Set up nRF24L01+ radio on SPI bus plus pins 9 and 10

unsigned int data[3] ;
const uint8_t buffer_size = sizeof(data);
const uint64_t pipes[2] = { 0xF0F0F0F0E1LL, 0xF0F0F0F0D2LL };//two pipes communication


//Declare the pins for the racing wheel
const int wheel_direction = A0;//

const int button_1A = 2;
const int Button_2A = 4;

const int button_1B = 3;
const int button_2B = 5;


void setup(void)
{
  Serial.begin(115200);
  pinMode(wheel_direction, INPUT );

  pinMode(button_1A, INPUT_PULLUP );
  pinMode(Button_2A, INPUT_PULLUP );
  pinMode(button_1B, INPUT_PULLUP );
  pinMode(button_2B, INPUT_PULLUP );

  radio.begin();
  radio.setPALevel( RF24_PA_MAX );  // Max power
  radio.setDataRate( RF24_250KBPS); // Min speed (for better range I presume)
  radio.setCRCLength( RF24_CRC_8);  // 8 bits CRC
  radio.setChannel(108);            //2.508 Ghz - Above most Wifi Channel
  radio.setRetries(15, 15);
  radio.openReadingPipe(1, pipes[1]);
  radio.startListening();
  radio.printDetails();
  radio.openWritingPipe(pipes[0]);
  radio.openReadingPipe(1, pipes[1]);
  radio.stopListening();

}

void loop(void)
{


  int wheel_value = analogRead(wheel_direction) / 10;

  data[0] = wheel_value;
  ////////////////////////////////////////////////////////////////////////

  if (digitalRead(button_1A) == LOW || digitalRead(Button_2A) == LOW  )   data[1] = 1;
  else   data[1] = 0;

  if ( digitalRead(button_1B) == LOW || digitalRead(button_2B) == LOW )   data[2] = 1;
  else   data[2] = 0;
  /////////////////////////////////////////////////////////////////////////

  /////////////////////////////////////////////////////////////////////////
  
  radio.stopListening();

  bool ok = radio.write(  data , sizeof(data) );
  delay(30);
  radio.startListening();
  delay(20);
  if (ok) {
    Serial.print("data[0]=");
    Serial.print(data[0]);
    Serial.print(" data[1]=");
    Serial.print(data[1]);
    Serial.print(" data[2]=");
    Serial.println(data[2]);

  }
  else
    Serial.println("Failed");

}//void loop()

Credits

Hugo Gomes

10 projects • 116 followers

http://www.hugogomes.net Youtube Channel - https://goo.gl/fnQLJo

FPV RC Car

Things used in this project

Hardware components

Software apps and online services

Hand tools and fabrication machines

Story

Components

Connect the Components

Code

Live Feed

Functional Test

Conclusion

Schematics

RX Schematic

TX Schematic

Code

Car_RX.ino

Car_TX.ino

Credits

Hugo Gomes

Comments

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FPV RC Car

FPV RC Car

Things used in this project

Hardware components

Software apps and online services

Hand tools and fabrication machines

Story

Components

Connect the Components

Code

Live Feed

Functional Test

Conclusion

Schematics

RX Schematic

TX Schematic

Code

Car_RX.ino

Car_TX.ino

Credits

Hugo Gomes

Comments

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