Best Cool Arduino Projects for Beginners At Home

 Obstacle Avoiding Car Using Ultrasonic :- 

#include <Servo.h>          //Servo motor library. This is standard library

#include <NewPing.h>        //Ultrasonic sensor function library. You must install this library

//our L298N control pins

const int LeftMotorForward = 7;

const int LeftMotorBackward = 6;

const int RightMotorForward = 4;

const int RightMotorBackward = 5;

//sensor pins

#define trig_pin A1 //analog input 1

#define echo_pin A2 //analog input 2

#define maximum_distance 200

boolean goesForward = false;

int distance = 100;

NewPing sonar(trig_pin, echo_pin, maximum_distance); //sensor function

Servo servo_motor; //our servo name

void setup(){

  pinMode(RightMotorForward, OUTPUT);

  pinMode(LeftMotorForward, OUTPUT);

  pinMode(LeftMotorBackward, OUTPUT);

  pinMode(RightMotorBackward, OUTPUT);

  

  servo_motor.attach(10); //our servo pin

  servo_motor.write(115);

  delay(2000);

  distance = readPing();

  delay(100);

  distance = readPing();

  delay(100);

  distance = readPing();

  delay(100);

  distance = readPing();

  delay(100);

}

void loop(){

  int distanceRight = 0;

  int distanceLeft = 0;

  delay(50);

  if (distance <= 20){

    moveStop();

    delay(300);

    moveBackward();

    delay(400);

    moveStop();

    delay(300);

    distanceRight = lookRight();

    delay(300);

    distanceLeft = lookLeft();

    delay(300);

    if (distance >= distanceLeft){

      turnRight();

      moveStop();

    }

    else{

      turnLeft();

      moveStop();

    }

  }

  else{

    moveForward(); 

  }

    distance = readPing();

}

int lookRight(){  

  servo_motor.write(50);

  delay(500);

  int distance = readPing();

  delay(100);

  servo_motor.write(115);

  return distance;

}

int lookLeft(){

  servo_motor.write(170);

  delay(500);

  int distance = readPing();

  delay(100);

  servo_motor.write(115);

  return distance;

  delay(100);

}

int readPing(){

  delay(70);

  int cm = sonar.ping_cm();

  if (cm==0){

    cm=250;

  }

  return cm;

}

void moveStop(){

  

  digitalWrite(RightMotorForward, LOW);

  digitalWrite(LeftMotorForward, LOW);

  digitalWrite(RightMotorBackward, LOW);

  digitalWrite(LeftMotorBackward, LOW);

}

void moveForward(){

  if(!goesForward){

    goesForward=true;

    

    digitalWrite(LeftMotorForward, HIGH);

    digitalWrite(RightMotorForward, HIGH);

  

    digitalWrite(LeftMotorBackward, LOW);

    digitalWrite(RightMotorBackward, LOW); 

  }

}

void moveBackward(){

  goesForward=false;

  digitalWrite(LeftMotorBackward, HIGH);

  digitalWrite(RightMotorBackward, HIGH);

  

  digitalWrite(LeftMotorForward, LOW);

  digitalWrite(RightMotorForward, LOW);

  

}

void turnRight(){

  digitalWrite(LeftMotorForward, HIGH);

  digitalWrite(RightMotorBackward, HIGH);

  

  digitalWrite(LeftMotorBackward, LOW);

  digitalWrite(RightMotorForward, LOW);

  

  delay(500);

  

  digitalWrite(LeftMotorForward, HIGH);

  digitalWrite(RightMotorForward, HIGH);

  

  digitalWrite(LeftMotorBackward, LOW);

  digitalWrite(RightMotorBackward, LOW);

 

  

  

}

void turnLeft(){

  digitalWrite(LeftMotorBackward, HIGH);

  digitalWrite(RightMotorForward, HIGH);

  

  digitalWrite(LeftMotorForward, LOW);

  digitalWrite(RightMotorBackward, LOW);

  delay(500);

  

  digitalWrite(LeftMotorForward, HIGH);

  digitalWrite(RightMotorForward, HIGH);

  

  digitalWrite(LeftMotorBackward, LOW);

  digitalWrite(RightMotorBackward, LOW);

}

Arduino Digital Clock :- 

const int clock = 11;

const int data = 10;

uint8_t digits[] = { 0x3f, 0x06, 0x5b, 0x4f, 0x66, 0x6d, 0x7d, 0x07, 0x7f, 0x6f };

void setup()

{

  setupInterrupt();

  pinMode(clock, OUTPUT);

  pinMode(data, OUTPUT);

  start();

  writeValue(0x8c);

  stop();

  write(0x00, 0x00, 0x00, 0x00);

}

byte tcnt2;

// set current time by editing the values at line 16 and 17

  unsigned long int setMinutes = 9; // set minutes

  unsigned long int setHours = 9;  // set hours

  unsigned long time = (setMinutes * 60 * 1000) + (setHours * 3600 *1000);

void setupInterrupt()

{

  TIMSK2 &= ~(1<<TOIE2);

  TCCR2A &= ~((1<<WGM21) | (1<<WGM20));

  TCCR2B &= ~(1<<WGM22);

  ASSR &= ~(1<<AS2);

  TIMSK2 &= ~(1<<OCIE2A);

  TCCR2B |= (1<<CS22)  | (1<<CS20); 

  TCCR2B &= ~(1<<CS21);

  tcnt2 = 131;

  TCNT2 = tcnt2;

  TIMSK2 |= (1<<TOIE2);

}

ISR(TIMER2_OVF_vect) {

  TCNT2 = tcnt2;

  time++;

  time = time % 86400000;

}

void loop()

{

  unsigned long t = (unsigned long)(time/1000);

  uint8_t minutes = (byte)((t / 60) % 60);

  uint8_t hours = (byte)((t / 3600) % 24);

  uint8_t seconds = (byte)(t % 60);

    write(digits[hours / 10], digits[hours % 10] | ((seconds & 0x01) << 7), digits[minutes / 10], digits[minutes % 10]);

}

void write(uint8_t first, uint8_t second, uint8_t third, uint8_t fourth)

{

  start();

  writeValue(0x40);

  stop();

  start();

  writeValue(0xc0);

  writeValue(first);

  writeValue(second);

  writeValue(third);

  writeValue(fourth);

  stop();

}

void start(void)

{

  digitalWrite(clock,HIGH);

  digitalWrite(data,HIGH);

  delayMicroseconds(5);

  digitalWrite(data,LOW);

  digitalWrite(clock,LOW);

  delayMicroseconds(5);

}

void stop(void)

{

  digitalWrite(clock,LOW);

  digitalWrite(data,LOW);

  delayMicroseconds(5);

  digitalWrite(clock,HIGH);

  digitalWrite(data,HIGH);

  delayMicroseconds(5);

}

bool writeValue(uint8_t value)

{

  for(uint8_t i = 0; i < 8; i++)

  {

    digitalWrite(clock, LOW);

    delayMicroseconds(5);

    digitalWrite(data, (value & (1 << i)) >> i);

    delayMicroseconds(5);

    digitalWrite(clock, HIGH);

    delayMicroseconds(5);

  }

  digitalWrite(clock,LOW);

  delayMicroseconds(5);

  pinMode(data,INPUT);

  digitalWrite(clock,HIGH);

  delayMicroseconds(5);

  bool ack = digitalRead(data) == 0;

  pinMode(data,OUTPUT);

  return ack;

}