Description

HC-SR04 Ultrasonic Ranging Sensor uses sonar to determine distance to an object like bats or dolphins do. It offers excellent non-contact range detection with high accuracy and stable readings in an easy-to-use package. From 2cm to 400 cm or 1” to 13 feet. It operation is not affected by sunlight or black material like Sharp rangefinders are (although acoustically soft materials like cloth can be difficult to detect). It comes complete with ultrasonic transmitter and receiver module.

HC-SR04 Ultrasonic Ranging Sensor Specifications

• Power supply: 5V DC
• Quiescent current: <2mA
• Effectual angle: <15°
• Ranging distance: 2cm – 400 cm
• Resolution: 1 cm
• Ultrasonic Frequency: 40k Hz
• Datasheet

Required Hardware Devices

• Arduino controller × 1
• HC-SR04 Ultrasonic Ranging Sensor
• USB data cable × 1

Connecting

• VCC -> Arduino +5V pin
• GND -> Arduino GND pin
• Trig -> Arduino Digital Pin 2
• Echo -> Arduino Digital Pin 4

Code

/* HC-SR04 Sensor This sketch reads a HC-SR04 ultrasonic rangefinder and returns the distance to the closest object in range. To do this, it sends a pulse to the sensor to initiate a reading, then listens for a pulse to return.  The length of the returning pulse is proportional to the distance of the object from the sensor. The circuit: * VCC connection of the sensor attached to +5V * GND connection of the sensor attached to ground * TRIG connection of the sensor attached to digital pin 2 * ECHO connection of the sensor attached to digital pin 4 Original code for Ping))) example was created by David A. Mellis Adapted for HC-SR04 by Tautvidas Sipavicius This example code is in the public domain. */ const int trigPin = 2; const int echoPin = 4; void setup() { // initialize serial communication: Serial.begin(9600); } void loop() { // establish variables for duration of the ping, // and the distance result in inches and centimetres: long duration, inches, cm; // The sensor is triggered by a HIGH pulse of 10 or more microseconds. // Give a short LOW pulse beforehand to ensure a clean HIGH pulse: pinMode(trigPin, OUTPUT); digitalWrite(trigPin, LOW); delayMicroseconds(2); digitalWrite(trigPin, HIGH); delayMicroseconds(10); digitalWrite(trigPin, LOW); // Read the signal from the sensor: a HIGH pulse whose // duration is the time (in microseconds) from the sending // of the ping to the reception of its echo off of an object. pinMode(echoPin, INPUT); duration = pulseIn(echoPin, HIGH); // convert the time into a distance inches = microsecondsToInches(duration); cm = microsecondsToCentimeters(duration); Serial.print(inches); Serial.print("in, "); Serial.print(cm); Serial.print("cm"); Serial.println(); delay(100); } long microsecondsToInches(long microseconds) { // According to Parallax's datasheet for the PING))), there are // 73.746 microseconds per inch (i.e. sound travels at 1130 feet per // second).  This gives the distance travelled by the ping, outbound // and return, so we divide by 2 to get the distance of the obstacle. // See: http://www.parallax.com/dl/docs/prod/acc/28015-PING-v1.3.pdf return microseconds / 74 / 2; } long microsecondsToCentimeters(long microseconds) { // The speed of sound is 340 m/s or 29 microseconds per centimeter. // The ping travels out and back, so to find the distance of the // object we take half of the distance travelled. return microseconds / 29 / 2; }