Arduino – Ultrasonic Sensor with LEDs and buzzer

Basically we have an Ultrasonic sensor that measures the distance and the LED’s bar graph will light up according to our distance from the sensor and as we get closer the buzzer beeps in a different way. This circuit can work as a parking sensor! It’s easy and cheap.

Parts Required

• Arduino UNO
• 1x 74HC595 8 Bit Shift Register
• 1x Breadboard
• 8x LEDs (for example: 3x red, 3x yellow, 2x green)
• 9x 220 Ohm Resistors
• 1x Buzzer
• 1x HC-SR04 Ultrasonic Sensor
• Jumper Wires

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Schematics

Upload the Code below

/*
 * created by Rui Santos, https://randomnerdtutorials.com
 * Ultrasonic Sensor with LED's bar graph and buzzer 
*/
int tonePin = 4;    //Tone - Red Jumper
int trigPin = 9;    //Trig - violet Jumper
int echoPin = 10;   //Echo - yellow Jumper
int clockPin = 11;  //IC Pin 11 - white Jumper
int latchPin = 12;  //IC Pin 12 - Blue Jumper
int dataPin = 13;   //IC Pin 14 - Green Jumper
 
byte possible_patterns[9] = {
B00000000, 
B00000001,
B00000011,
B00000111,
B00001111,
B00011111,
B00111111, 
B01111111, 
B11111111,
};
int proximity=0;
int duration;
int distance;
 
void setup() {
  //Serial Port
  Serial.begin (9600);
  
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(clockPin, OUTPUT);
  pinMode(latchPin, OUTPUT);
  pinMode(dataPin, OUTPUT);
  pinMode(tonePin, OUTPUT);
}
 
void loop() {
  digitalWrite(latchPin, LOW);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(1000);
  digitalWrite(trigPin, LOW);
  duration = pulseIn(echoPin, HIGH);
  distance = (duration/2) / 29.1;
  
  /*if (distance >= 45 || distance <= 0){
    Serial.println("Out of range");
  }
  else {
    Serial.print(distance);
    Serial.println(" cm");
  }*/
  
  proximity=map(distance, 0, 45, 8, 0);
  //Serial.println(proximity);
  
  if (proximity <= 0){
    proximity=0;
  }
  else if (proximity >= 3 && proximity <= 4){
    tone(tonePin, 200000, 200);
  }
  else if (proximity >= 5 && proximity <= 6){
     tone(tonePin,5000, 200);
  }
  else if (proximity >= 7 && proximity <= 8){
    tone(tonePin, 1000, 200);
  }
  shiftOut(dataPin, clockPin, MSBFIRST, possible_patterns[proximity]);
  digitalWrite(latchPin, HIGH);
 
  
  delay(600);
  noTone(tonePin);
}

View raw code

Watch the video demonstration