Tip: Get fun!!

Introduction

First of all... What is Arduino? Arduino is a mini computer that receives some inputs, processes them and give other outputs

Ultrasounds Sensor gives the distances of objects in front of the car
The microprocessor (Arduino) receives the distances from the sensor:
- If there is no object continues moving forward
- If there is an object in front turns left to avoid it
The microprocessor (Arduino) gives the order to motor controller and the controller order to the wheels to move

Important: Watch the car in action!!

Materials

Arduino UNO R3 - basic kit : 23.99 €

Wheels and motors kit : 21.00 €

DC motor controller (L293D): 1.60 €

Electrical insulation tape

Ultrasounds Sensor HC-SR04 - 2.70 €

5 V Power Supply

Chipboard sheets for crafts : 7.37 €

PC with Arudino IDE installed

Connect the motor controller, Arduino and the motors.

Follow this tutorial

This is the result:

Connect the ultrasounds Sensor to arduino

This is the result:

Assembling the components

In a piece of chipboard attach the motors.
Put the wheels

Attach the power bank

Attach the motor controller
Attach Arduino UNO microcontroller board

Attach the ultrasounds Sensor in front of the car

Program Arduino

First, install Arduino IDE (Integrated Development Environment)

Open the program:

Programming basics:

The computer executes instructions one after the other. I1 -> I2 -> I3 ....

Each instruction ends with ";"

To store information use:

Constants: its value does not change (for example: const int pinIqda = 9;)
Variables: its value changes over the time (for example: int distancia=0; distancia= distancia + 2 )

There are two main parts (funtions) in Arduino:

Setup(): it runs only once at start
Loop(): it repeats endlessly

Use "//" to write comments in the code Use "{ }" to build a set of instructions

Control the program flow: IF

Other usefull functions:

pinMode (1, OUTPUT) or pinMode (1, INPUT) : sets a arduino pin to receive inputs o give outputs
analogWrite or digitalWrite: sends information throught pins
Serial.print : writes something in the monitor
delay(1000) : makes the program to wait 1000 miliseconds.

Now, write the code in Arduino IDE.

Check if the code is ok: press

Conect Ardunio and the computer with USB
Transfer the code to Arduino: press

The final code

NewPing sonar(12,11, 200); // Pin 12 and 11 for the ultrasonic sensor and with a maximum distance of 200cm

const int pinIqda = 9;
const int pinDcha = 10;
const int pinIqdaAdelante = 8;
const int pinIqdaAtras = 3;
const int pinDchaAdelante = 6;
const int pinDchaAtras= 5;

int distancia=0;

void setup()   //  initial instructions
{
  
  // configure arduino pins
  pinMode(pinIqda , OUTPUT);
  analogWrite(pinIqda, 254);  // left speed, set up to max
  pinMode(pinDcha , OUTPUT);
  analogWrite(pinDcha, 254);  //  right speed, set up to max
  pinMode(pinIqdaAdelante , OUTPUT);
  pinMode(pinIqdaAtras , OUTPUT);
  pinMode(pinDchaAdelante , OUTPUT);
  pinMode(pinDchaAtras , OUTPUT);
  
  Serial.begin(9600); // show ping meassures
  
  // start the engines
  digitalWrite(pinIqdaAdelante ,HIGH);  
  digitalWrite(pinIqdaAtras , LOW );  
  digitalWrite(pinDchaAdelante , HIGH);
  digitalWrite(pinDchaAtras ,LOW);   
  
}

void loop()    // Instructions that repeat themselves endlessly
{
  delay(1000);  // wait 1000 miliseconds between ping
  distancia=sonar.ping()/ US_ROUNDTRIP_CM;
  
  Serial.print("Ping: ");  
  Serial.print(distancia); // 
  Serial.println("cm");
  
  if (distancia>2 && distancia<50  ) {  // turn left
    digitalWrite(pinIqdaAdelante ,LOW);  
    digitalWrite(pinIqdaAtras, HIGH );  
    digitalWrite(pinDchaAdelante , HIGH);
    digitalWrite(pinDchaAtras , LOW);  
    delay(3000);   // wait 3 iseconds to turn left
    
  }

    if (distancia>=50  ){       //   go forward
    digitalWrite(pinIqdaAdelante ,HIGH);  
    digitalWrite(pinIqdaAtras , LOW );  
    digitalWrite(pinDchaAdelante , HIGH);
    digitalWrite(pinDchaAtras ,LOW);     
 }
}

Arduino Car Proyect