Ultrasonic Sensor with Arduino

The HC-SR04 ultrasonic sensor uses SONAR to determine the distance of an object just like the bats do. It offers excellent non-contact range detection with high accuracy and stable readings in an easy-to-use package from 2 cm to 400 cm or 1” to 13 feet.

The operation is not affected by sunlight or black material, although acoustically, soft materials like cloth can be difficult to detect. It comes complete with ultrasonic transmitter and receiver module.

Technical Specifications

• Power Supply − +5V DC
• Quiescent Current − <2mA
• Working Current − 15mA
• Effectual Angle − <15°
• Ranging Distance − 2cm – 400 cm/1″ – 13ft
• Resolution − 0.3 cm
• Measuring Angle − 30 degree

The ultrasonic sensor HC-SR04 includes four pins:

• VCC pin needs to be connected to VCC (5V)
• GND pin needs to be connected to GND (0V)
• TRIG pin this pin receives the control signal (pulse) from Arduino.
• ECHO pin this pin sends a signal (pulse) to Arduino. Arduino measures the duration of pulse to calculate distance. 
• How It Works
  This section is the in-depth knowledge. DON'T worry if you don't understand. Ignore this section if it overloads you, and come back in another day. Keep reading the next sections.

1. 1.  Micro-controller: generates a 10-microsecond pulse on the TRIG pin.
2. 2. The ultrasonic sensor automatically emits the ultrasonic waves.
3. 3. The ultrasonic wave is reflected after hitting an obstacle.
4. 4. The ultrasonic sensor:

Detects the reflected ultrasonic wave.

• Measures the travel time of the ultrasonic wave.
1. 5. Ultrasonic sensor: generates a pulse to the ECHO pin. The duration of the pulse is equal to the travel time of the ultrasonic wave.
2. 6. Micro-controller measures the pulse duration in the ECHO pin, and then calculate the distance between sensor and obstacle.

3. Components Required

   You will need the following components −
   • 1 × Breadboard
   • 1 × Arduino Uno R3
   • 1 × ULTRASONIC Sensor (HC-SR04)

Procedure

Follow the circuit diagram and make the connections as shown in the image given below.

Sketch

Open the Arduino IDE software on your computer. Coding in the Arduino language will control your circuit. Open a new sketch File by clicking New.

Arduino Code

/*******
 All the resources for this project:
 https://lihuo.blogspot.com

*******/

const int pingPin = 11; // Trigger Pin of Ultrasonic Sensor
const int echoPin = 12; // Echo Pin of Ultrasonic Sensor

long microsecondsToInches(long microseconds) {   return microseconds / 74 / 2; }
long microsecondsToCentimeters(long microseconds) {   return microseconds / 29 / 2; }

void setup() {
   Serial.begin(9600); // Starting Serial Terminal
}
void loop() {
   long duration, inches, cm;
   pinMode(pingPin, OUTPUT);
   digitalWrite(pingPin, LOW);
   delayMicroseconds(2);
   digitalWrite(pingPin, HIGH);
   delayMicroseconds(10);
   digitalWrite(pingPin, LOW);
   pinMode(echoPin, INPUT);
   duration = pulseIn(echoPin, HIGH);
   inches = microsecondsToInches(duration);
   cm = microsecondsToCentimeters(duration);
   Serial.print(inches);
   Serial.print("in, ");
   Serial.print(cm);
   Serial.print("cm");
   Serial.println();
   delay(100);

} Code to Note

The Ultrasonic sensor has four terminals - +5V, Trigger, Echo, and GND connected as follows −

• Connect the +5V pin to +5v on your Arduino board.
• Connect Trigger to digital pin 7 on your Arduino board.
• Connect Echo to digital pin 6 on your Arduino board.
• Connect GND with GND on Arduino.

In our program, we have displayed the distance measured by the sensor in inches and cm via the serial port.

Result

You will see the distance measured by sensor in inches and cm on Arduino serial monitor.