When an object comes close the hc-sr04 ultrasonic sensor indicates the distance using led. the first led will turn off at a distance of 7cm and the other leds will turn off every 7cm added. An ultrasonic sensor-led project is something like a scale for finding the distance measure of an object. we can easily extend the range of the Hc-sr04 sensor to changing code. 

 

 

 

 

 

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Requirement:
1. Arduino Uno 
2. Ultrasonic sensor Hc-sr04
3. 7 x LEDs
4. 7 x 220ohm resistor
5. Breadboard 
6. jumper wire 

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Coding:

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//Define variables

const int trig = 12;

const int echo = 13;

const int LED1 = 8;

const int LED2 = 7;

const int LED3 = 6;

const int LED4 = 5;

const int LED5 = 4;

const int LED6 = 3;

const int LED7 = 2;

int duration = 0;

int distance = 0;

 

void setup()

{

//Define the leds pins

  pinMode(trig , OUTPUT);

  pinMode(echo , INPUT);

  pinMode(LED1 , OUTPUT);

  pinMode(LED2 , OUTPUT);

  pinMode(LED3 , OUTPUT);

  pinMode(LED4 , OUTPUT);

  pinMode(LED5 , OUTPUT);

  pinMode(LED6 , OUTPUT);

  pinMode(LED7 , OUTPUT);

  Serial.begin(9600);

 

}

 

void loop()

{

//running the code and defining the distance for turning the leds on

  digitalWrite(trig , HIGH);

  delayMicroseconds(1000);

  digitalWrite(trig , LOW);

  duration = pulseIn(echo , HIGH);

  distance = (duration/2) / 28.5 ;

  Serial.println(distance);

//experiencing the distances

   if ( distance <= 7 )

  {

    digitalWrite(LED1, HIGH);

  }

  else

  {

    digitalWrite(LED1, LOW);

  }

  if ( distance <= 14 )

  {

    digitalWrite(LED2, HIGH);

  }

  else

  {

    digitalWrite(LED2, LOW);

  }

  if ( distance <= 21 )

  {

    digitalWrite(LED3, HIGH);

  }

  else

  {

    digitalWrite(LED3, LOW);

  }

  if ( distance <= 28 )

  {

    digitalWrite(LED4, HIGH);

  }

  else

  {

    digitalWrite(LED4, LOW);

  }

  if ( distance <= 35 )

  {

    digitalWrite(LED5, HIGH);

  }

  else

  {

    digitalWrite(LED5, LOW);

  }

  if ( distance <= 42 )

  {

    digitalWrite(LED6, HIGH);

  }

  else

  {

    digitalWrite(LED6, LOW);

  }

  if ( distance <= 49 )

  {

    digitalWrite(LED7, HIGH);

  }

  else

  {

    digitalWrite(LED7, LOW);

  }

}