Introduction
I already made a video about it on youtube. Here I explain everything, that’s why I will not write it again here.
But I will add some mark points and information that can be useful. Also I will place the arduino code underneed.
additional information
Like you saw it, this car has a lot of lights, even actually too many which cause some troubles with
the power consumption. For the whole car, I’m using two little rechargeable 9v batteries. These are too
small to power the arduino, 3 motors and all the leds. That’s why my first recommendation is : be careful
with the battery consumption.
Sometimes you will wonder why the nRF24l01 radio module isn’t working. You can then try to place a little condensator between the positif and negatif pins of the module.
Sometimes you will wonder why the nRF24l01 radio module isn’t working. You can then try to place a little condensator between the positif and negatif pins of the module.
Arduino receiver code
#include // library for SPI pipe between UNO and NRF24L01
#include // library for NRF24L01 module
#include // library for radio module
#include // library to control the servo motor
RF24 radio(7, 8); // initialise the radio pin for CE ans CSN (pin 7 and 8)
const byte address[6] = "00001"; // Address (same fot receiver and transmitter)
Servo servo1; // name of the servo motor (servo1)
int servo1Value; // variable for the value (degree) of the servo motor
int ledState = LOW; // variable to make the leds blinking (more info downstair)
unsigned long previousMillis = 0; // variable to make the leds blinking (more info downstair)
unsigned long interval = 400; // variable for time that the leds gonna blink (400 milliseconds = 0.4 sec)
int ledState2 = LOW; // variable to make the leds blinking (more info downstair)
unsigned long previousMillis2 = 0; // variable to make the leds blinking (more info downstair)
unsigned long interval2 = 400; // variable for time that the leds gonna blink (400 milliseconds = 0.4 sec)
struct Data_Package // Initialise a structure with the data we gonna receive
{
byte tSwitch1; // variable for the data that we receive from tSwitch1 (toggle switch 1) Need to be the same on the receiver and the transmitter
byte tSwitch2; // variable for the data that we receive from tSwitch2 (toggle switch 2) Need to be the same on the receiver and the transmitter
byte tSwitch3; // variable for the data that we receive from tSwitch3 (toggle switch 3) Need to be the same on the receiver and the transmitter
byte tSwitch4; // variable for the data that we receive from tSwitch4 (toggle switch 4) Need to be the same on the receiver and the transmitter
byte j1PotX; // variable for the data that we receive from the X-axe of the joystick Need to be the same on the receiver and the transmitter
byte j1PotY; // variable for the data that we receive from the Y-axe of the joystick Need to be the same on the receiver and the transmitter
byte j1Button; // variable for the data that we receive from the button of the joystick Need to be the same on the receiver and the transmitter
};
Data_Package data; // Create a variable with the above structure
void setup() // SETUP SECTION : first think that the arduino gonna do (1 time)
{
Serial.begin(9600); // initialise the Serial communication to 9600 bits/second
radio.begin(); // initialise the Radio communication
radio.openReadingPipe(0, address); // initialise the radio module for reading (receiver) on the address that we set upstair (00001)
radio.setAutoAck(false); // initialise the radio module
radio.setDataRate(RF24_250KBPS); // initialise the radio module
radio.setPALevel(RF24_PA_LOW); // initialise the radio communication
radio.startListening(); // put the radio module on receiver mode (NRF24L01 can be use as a receiver and a transmitter at the same time)
pinMode(2, OUTPUT); // initialise pin 2 to output for the led of the turn signal
pinMode(5, OUTPUT); // initialise pin 5 to output for the led of the turn signal
pinMode(6, OUTPUT); // initialise pin 6 to output for the led of the front lights
pinMode(3, OUTPUT); // initialise pin 3 to output for the led of the rear lights
pinMode(9, OUTPUT); // initialise pin 9 to control the sense of the motor
pinMode(10, OUTPUT); // initialise pin 10 to control the sense of the motor
pinMode(0, OUTPUT); // initialise pin 12 to output for the buzzer speaker
servo1.attach(4); // initialise pin 4 to the place were the servo motor is attached
}
void loop() // LOOP SECTION : after the setup section, the Arduino gone do this all the time until he has no power more
{
if (radio.available()) // if the radio available something, he ...
{
radio.read(&data, sizeof(Data_Package)); // read all the data that he receive
}
//..................................................................................................................................................................
servo1Value = map(data.j1PotX, 0, 255, 0, 70); // take the last data of the x-axis of the joystick that he receive and change this one into value to 0 and 70
servo1.write(servo1Value); // make the servo turning with the value that we make above (0, 70 degrees)
//..................................................................................................................................................................
if (data.tSwitch1 == HIGH) // if the last data of the toggle switch (1) = 1 ...
{
unsigned long currentMillis = millis(); // make a variable with the millis() (time sinds the arduino is on)
if (currentMillis - previousMillis > interval) // if we have a interval from more than 400 millisecund than we ...
{
previousMillis = currentMillis; // say that previousMillis is now egual to currentMillis
if (ledState == LOW) // if ledstate was LOW (off)...
{
(ledState = HIGH); // ledState is now HIGH
}
else // if ledState was HIGH (on) ...
{
(ledState = LOW); // ledState is now LOW
}
digitalWrite(2, ledState); // put the led on or off is function of ledState
}
}
else // if the last data of the toggle switch 1 = 0 ...
{
digitalWrite(2, LOW); // put the led off
}
// This proces is very useful if you want to make an interruption without using function delay()
//..................................................................................................................................................................
if (data.tSwitch2 == HIGH) // if the last data of the toggle switch 2 = 1 ...
{
unsigned long currentMillis2 = millis(); // make a variable with the millis() (time sinds the arduino is on)
if (currentMillis2 - previousMillis2 > interval2) // if we have a interval from more than 400 millisecund than we ...
{
previousMillis2 = currentMillis2; // say that previousMillis is now egual to currentMillis
if (ledState2 == LOW) // if ledstate was LOW (off)...
{
(ledState2 = HIGH); // ledState is now HIGH
}
else // if ledState was HIGH (on) ...
{
(ledState2 = LOW); // ledState is now LOW
}
digitalWrite(5, ledState2); // put the led on or off is function of ledState
}
}
else // if the last data of the toggle switch 2 = 0 ...
{
digitalWrite(5, LOW); // put the led off
}
// This proces is very useful if you want to make an interruption without using function delay()
//..................................................................................................................................................................
if (data.tSwitch3 == HIGH) // if the last data of the toggle switch 3 = 1 ...
{
digitalWrite(6, HIGH); // put the led on
}
else // if the last data of the toggle switch 3 = 0 ...
{
digitalWrite(6, LOW); // put the led off
}
//.................................................................................................................................................................
if (data.tSwitch4 == HIGH) // if the last data of the toggle switch 4 = 1 ...
{
digitalWrite(0, HIGH); // put the led on
}
else // if the last data of the toggle switch 4 = 0 ...
{
digitalWrite(0, LOW); // put the led off
}
//.................................................................................................................................................................
if (data.j1PotY > 150) // if the last data from the y-axis of the joystick is greater than 150 ...
{
digitalWrite(9, LOW); // pin 9 and 10 are antagonist to make the motor turn in one sense
digitalWrite(10, HIGH); // pin 9 and 10 are antagonist to make the motor turn in one sense
analogWrite(11, HIGH); // control the energy that's coming from the 9V battery (HIGH = max power of the battery)
}
if (data.j1PotY < 104) // if the last data from the y-axis of the joystick is less than 104 ...
{
digitalWrite(9, HIGH); // pin 9 and 10 are antagonist to make the motor turn in one sense
digitalWrite(10, LOW); // pin 9 and 10 are antagonist to make the motor turn in one sense
analogWrite(11, HIGH); // control the energy that's coming from the 9V battery (HIGH = max power of the battery)
}
if (data.j1PotY > 104 && data.j1PotY < 150) // if the last data from the y-axis of the joystick is between 104 and 150 than ...
{
digitalWrite(9, LOW); // pin 9 and 10 are the same. So the motor can't drive
digitalWrite(10, LOW); // pin 9 and 10 are the same. So the motor can't drive
}
//.................................................................................................................................................................
if (data.j1Button == 0) // if the last data of the joystick button = 0 ...
{
tone (3, 75); // pit a frequency of 75 Hz on pin 3 (claxon)
}
else // if the last data of the joystick button = 1 ...
{
noTone(3); // send no frequency
}
//................................................................................................................................................................
// like the transmitter we send the data on the serial communication so that we can see if we have a problem.
// If the value of the transmitter is not the same as for the receiver than you have a problem with the communication
Serial.println(data.tSwitch1); // send data to the serial communication
Serial.println(data.tSwitch2); // send data to the serial communication
Serial.println(data.tSwitch3); // send data to the serial communication
Serial.println(data.tSwitch4); // send data to the serial communication
Serial.println(data.j1PotX); // send data to the serial communication
Serial.println(data.j1PotY); // send data to the serial communication
Serial.println(data.j1Button); // send data to the serial communication
delay(200); // wait 200 millisecund so that you have less bugs but you gonna have less precision
}
Arduino transmitter code
#include // library for SPI pipe between UNO and NRF24L01
#include // library for NRF24L01 module
#include // library for radio modules
#include // library for NRF24L01 module
#define t1 2 // define toggle switch 1 on pin 2
#define t2 4 // define toggle switch 2 on pin 4
#define t3 5 // define toggle switch 3 on pin 5
#define t4 3 // define toggle switch 4 on pin 3
#define b1 6 // define joystick button on pin 6
RF24 radio(7, 8); // We need to say were we put the CE and CSN pin (7 = CE, 8 = CSN)
const byte address[6] = "00001"; // Address (same for receiver and transmitter)
struct Data_Package // Initialise a structure with the data that we gonna send
{
byte tSwitch1; // data from toggle switch 1 Need to be the same on the receiver and the transmitter
byte tSwitch2; // data from toggle switch 2 Need to be the same on the receiver and the transmitter
byte tSwitch3; // data from toggle switch 3 Need to be the same on the receiver and the transmitter
byte tSwitch4; // data from toggle switch 4 Need to be the same on the receiver and the transmitter
byte j1PotX; // data from the x-axis of the joystick Need to be the same on the receiver and the transmitter
byte j1PotY; // data from the y-axis of the joystick Need to be the same on the receiver and the transmitter
byte j1Button; // data from the button of the joystick Need to be the same on the receiver and the transmitter
};
Data_Package data; // create a variable with the above structure
void setup() // SETUP SECTION : first think that the arduino gonna do (1 time)
{
Serial.begin(9600); // initialise the serial communication to 9600 bits/second
radio.begin(); // initialise the Radio communication
radio.openWritingPipe(address); // initialise the radio module for reading (receiver) on the address that we set upstair (00001)
radio.setAutoAck(false); // initialise the Radio module
radio.setDataRate(RF24_250KBPS); // initialise the Radio module
radio.setPALevel(RF24_PA_LOW); // initialise the Radio communication
pinMode(t1, INPUT_PULLUP); // Initialse pin t1 (2) as INPUT_PULLUP
pinMode(t2, INPUT_PULLUP); // Initialse pin t2 (4) as INPUT_PULLUP
pinMode(t3, INPUT_PULLUP); // Initialse pin t3 (5) as INPUT_PULLUP
pinMode(t4, INPUT_PULLUP); // Initialse pin t4 (3) as INPUT_PULLUP
pinMode(b1, INPUT_PULLUP); // Initialse pin b1 (6) as INPUT_PULLUP
data.tSwitch1 = 1; // initialise the data of toggle switch 1 to 1
data.tSwitch2 = 1; // initialise the data of toggle switch 2 to 1
data.tSwitch3 = 1; // initialise the data of toggle switch 3 to 1
data.tSwitch4 = 1; // initialise the data of toggle switch 4 to 1
data.j1PotX = 127; // initialise the data of the x-axis of the joystick to 127
data.j1PotY = 127; // initialise the data of the y-axis of the joystick to 127
data.j1Button = 1; // initialise the data of the joystick button to 1
}
void loop() // LOOP SECTION : after the setup section, the arduino gonna do this all time until he has no power more
{
data.tSwitch1 = digitalRead(t1); // Say that he can find the value of toggle 1 by reading pin t1 (2)
data.tSwitch2 = digitalRead(t2); // Say that he can find the value of toggle 2 by reading pin t2 (4)
data.tSwitch3 = digitalRead(t3); // Say that he can find the value of toggle 3 by reading pin t1 (5)
data.tSwitch4 = digitalRead(t4); // Say that he can find the value of toggle 4 by reading pin t1 (4)
data.j1PotX = map(analogRead(A2), 0, 1023, 0, 255); // Find the value of the x-axis of the joystick on pin A2. He need to change the value from 0-1023 to 0-255
data.j1PotY = map(analogRead(A0), 0, 1023, 0, 255); // Find the value of the y-axis of the joystick on pin A0. He need to change the value from 0-1023 to 0-255
data.j1Button = digitalRead(b1); // Say that he can find the value of the joystick button by reading pin b1 (6)
radio.write(&data, sizeof(Data_Package)); // send all the data that he collected from the sensors. (Data_package = structure that we create before)
// We put the data on the Serial communication so that we see what the problem is if it's not working
Serial.println(data.tSwitch1); // put the value of toggle 1 on the serial communication
Serial.println(data.tSwitch2); // put the value of toggle 2 on the serial communication
Serial.println(data.tSwitch3); // put the value of toggle 3 on the serial communication
Serial.println(data.tSwitch4); // put the value of toggle 4 on the serial communication
Serial.println(data.j1PotX); // put the value of the x-axis of the joystick on the serial communication
Serial.println(data.j1PotY); // put the value of the y-axis of the joystick on the serial communication
Serial.println(data.j1Button); // put the value of the joystick button on the serial communication
delay(200); // wait 200 milliseconds before making this block again
// This one need to be high to have no bugs but we lose precision.
}
conclusion
I hope you find it interesting. Building an rc car is a good beginner tutorial. Don't forget
to see my other projects. ;-)