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ejshea
Published © GPL3+

Interface an Ultrasonic Sensor

Learn how an ultrasonic sensor works and how to interface it to an Arduino Uno.

BeginnerFull instructions provided5,403
Interface an Ultrasonic Sensor

Things used in this project

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Arduino IDE
Arduino IDE

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Schematics

Final Schematic

Code

Parallax Ultrasonic Sensor

Arduino
//Interface a PING ultrasonic sensor which uses ultrasonic waves to measure distance
//It consists of 3 pins: GND, 5V, and SIG
//Datasheet available: https://www.parallax.com/sites/default/files/downloads/28015-PING-Sensor-Product-Guide-v2.0.pdf

#include <LiquidCrystal.h>

//variable declarations
long duration;
int distancecm;
long distancein;
const int RS = 2, EN = 3, D4 = 4, D5 = 5, D6 = 6, D7 = 7;

LiquidCrystal lcd(RS,EN,D4,D5,D6,D7);   //set Uno pins that are connected to LCD, 4-bit mode

void setup() {
  lcd.begin(16,2);          //set 16 columns and 2 rows of 16x2 LCD
  pinMode(8, OUTPUT);
  digitalWrite(8, LOW);     
}

void loop() {
  //Trigger the sensor with a 2usec HIGH pulse
  digitalWrite(8, HIGH);
  delayMicroseconds(2);
  digitalWrite(8, LOW);

  pinMode(8, INPUT);              //set pin as input to read return pulse from sensor
  duration = pulseIn(8, HIGH);    //obtain length of HIGH pulse in microseconds

  //Ping sensor returns HIGH output pulse that gives the time required for the burst
  //echo to return back to the sensor 

  //Speed of sound travels at 1130ft/sec (0.00113ft/usec) or 340m/sec (0.034cm/usec)
  //Must divide by 2 since time received is time for sound wave to travel to and from object

  //Calculate distance in inches and centimeters
  distancecm = duration*0.034/2;
  distancein = distancecm*0.3937;     //1cm = 0.3937in

  //display distance to LCD
  lcd.clear();
  lcd.print("Distance: ");
  lcd.print(distancecm);
  lcd.print("cm");
  lcd.setCursor(10,1);
  lcd.print(distancein);
  lcd.print("in");
  delay(200);
  pinMode(8, OUTPUT);               //set pin 8 back to an output to trigger next distance measurement
  digitalWrite(8, LOW);

}

HC-SR04 Ultrasonic Sensor

Arduino
//Interface a HC-SR04 module which uses ultrasonic waves to measure distance
//It consists of 4 pins: VCC, TRIG, ECHO, and GND

#include <LiquidCrystal.h>

//variable declarations
long duration;
int distancecm;
long distancein;
const int RS = 2, EN = 3, D4 = 4, D5 = 5, D6 = 6, D7 = 7;

LiquidCrystal lcd(RS,EN,D4,D5,D6,D7);   //set Uno pins that are connected to LCD, 4-bit mode

void setup() {
  lcd.begin(16,2);          //set 16 columns and 2 rows of 16x2 LCD
  pinMode(8, OUTPUT);       //TRIG pin
  pinMode(9, INPUT);        //ECHO pin
  digitalWrite(8, LOW);     //set TRIG pin low
}

void loop() {
  //Trigger the sensor with a 10usec HIGH pulse
  digitalWrite(8, HIGH);
  delayMicroseconds(10);
  digitalWrite(8, LOW);

  duration = pulseIn(9, HIGH);    //obtain length of HIGH pulse in microseconds

  //HIGH output pulse is returned that gives the time required for the burst
  //echo to return back to the sensor 

  //Speed of sound travels at 1130ft/sec (0.00113ft/usec) or 340m/sec (0.034cm/usec)
  //Must divide by 2 since time received is time for sound wave to travel to and from object

  //Calculate distance in inches and centimeters
  distancecm = duration*0.034/2;
  distancein = distancecm*0.3937;     //1cm = 0.3937in

  //display distance to LCD
  lcd.clear();
  lcd.print("Distance: ");
  lcd.print(distancecm);
  lcd.print("cm");
  lcd.setCursor(10,1);
  lcd.print(distancein);
  lcd.print("in");
  delay(200);

}

Credits

ejshea

ejshea

16 projects • 30 followers

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