Using the ultrasonic sensor with Arduino - Complete Guide in 2023

 Ultrasonic sensors have become increasingly popular in recent years, particularly in the field of IoT. They are used in a wide range of applications such as distance measurement, object detection, and obstacle avoidance. The ultrasonic sensor works by emitting high-frequency sound waves and then measuring the time it takes for the waves to bounce back. This information can then be used to calculate the distance between the sensor and the object.

In this article, I will provide a complete guide on using an ultrasonic sensor with Arduino. I will discuss the principles behind ultrasonic sensors and provide a step-by-step guide on how to connect and use the ultrasonic sensor with Arduino. I will also provide a circuit diagram and complete code to help you get started.

Principles Behind Ultrasonic Sensors HC-SR04

Ultrasonic sensors work by emitting high-frequency sound waves that are beyond the range of human hearing. These sound waves bounce off any object in their path and return to the sensor. By measuring the time it takes for the sound waves to return, the sensor can determine the distance between the object and the sensor.

The ultrasonic sensor consists of two main parts, the transmitter and the receiver. The transmitter emits the sound waves, while the receiver detects the waves that bounce back. The sensor calculates the distance by measuring the time it takes for the sound waves to travel to the object and back.

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Using Ultrasonic Sensor with Arduino

Now that we understand the principles behind ultrasonic sensors let's move on to connecting and using the sensor with an Arduino.

Hardware Required

• Arduino Uno
• Ultrasonic Sensor HC-SR04
• Breadboard
• Jumper wires
• USB cable

Ultrasonic Sensor with Arduino Circuit Diagram

To get started, we need to connect the ultrasonic sensor with Arduino. Follow the circuit diagram below to make the necessary connections:

Ultrasonic Sensor HC-SR04 Pins	Arduino UNO Pins
VCC	+5V
GND	GND
TRIG	D9
ECHO	D10

The ultrasonic sensor HC-SR04 has four pins: VCC, GND, TRIG, and ECHO. Connect the VCC and GND pins of the sensor to the +5V and GND pins of the Arduino, respectively. Connect the TRIG and ECHO pins of the sensor to pins 9 and 10 of the Arduino, respectively.

 

Ultrasonic Sensor Arduino Code

Once you have made the necessary connections, it's time to upload the ultrasonic sensor code to the Arduino. Open the Arduino IDE and copy the following code:

#define trigPin 9
#define echoPin 10

void setup() {
  Serial.begin(9600); // initialize serial communication
  pinMode(trigPin, OUTPUT); // set the trig pin as output
  pinMode(echoPin, INPUT); // set the echo pin as input
}

void loop() {
  // set trig pin to high for 10 microseconds
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  // measure the time taken for the sound wave to bounce back
  long duration = pulseIn(echoPin, HIGH);

  // calculate the distance based on the time taken
  float distance = duration * 0.034 / 2;

  // print the distance to the serial monitor
  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.println(" cm");

  // wait for 500 milliseconds before taking another measurement
  delay(500);
}

The code above initializes the serial communication and sets the TRIG and ECHO pins as output and input, respectively. In the loop function, the code sends a sound wave from the TRIG pin and measures the time taken for the wave to bounce back using the ECHO pin. The distance is then calculated based on the time taken and printed to the serial monitor. Finally, the code waits for 500 milliseconds before taking another measurement.

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Explanation of Code

Let's take a closer look at the code and how it works.

#define trigPin 9
#define echoPin 10

Here, we define the trig and echo pins as 9 and 10, respectively.

void setup() {
  Serial.begin(9600);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
}

In the setup function, we initialize the serial communication and set the trig and echo pins as output and input, respectively.

void loop() {
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  long duration = pulseIn(echoPin, HIGH);

  float distance = duration * 0.034 / 2;

  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.println(" cm");

  delay(500);
}

In the loop function, we send a 10 microsecond pulse from the TRIG pin. The sound wave then travels to the object and bounces back to the sensor. The duration of the pulse is measured using the pulseIn function and stored in the duration variable.

The distance is then calculated using the formula

distance = duration * 0.034 / 2

This formula is based on the speed of sound in air, which is approximately 340 m/s. Since the sound wave has to travel to the object and back, we divide the duration by 2. The result is the distance in centimeters.

Finally, we print the distance to the serial monitor and wait for 500 milliseconds before taking another measurement.

Conclusion

In this article, we discussed the principles behind ultrasonic sensors and how to use them with an Arduino. We provided a step-by-step guide on how to connect the sensor to the Arduino and wrote a complete code to measure the distance to an object using the sensor. With this knowledge, you can now start experimenting with ultrasonic sensors and develop your own projects.

Note: It's important to note that the ultrasonic sensor HC-SR04 sensor requires a 5V power supply and is not compatible with 3.3V Arduino boards. Make sure you check the voltage compatibility of your components before connecting them.

FAQs

1. Can I use any ultrasonic sensor with Arduino? No, not all ultrasonic sensors are compatible with Arduino. You need to make sure that the sensor you are using operates at 5V and has separate TRIG and ECHO pins. The HC-SR04 sensor is a popular choice for Arduino projects and is easy to use.
2. How accurate are ultrasonic sensors? The accuracy of ultrasonic sensors depends on a variety of factors such as the quality of the sensor, the distance to the object being measured, and environmental conditions such as temperature and humidity. Generally, ultrasonic sensors are accurate to within a few millimeters.
3. What is the maximum range of an ultrasonic sensor? The maximum range of an ultrasonic sensor varies depending on the model and specifications of the sensor. The HC-SR04 sensor has a maximum range of 4 meters, while some other sensors can measure distances up to 10 meters or more.
4. How do I troubleshoot my ultrasonic sensor? If you are having trouble getting accurate readings from your ultrasonic sensor, check the wiring to make sure it is connected correctly. Also, make sure that the sensor is powered with a stable 5V supply. If the problem persists, you can try using a different sensor or adjusting the code to improve the accuracy of the readings.
5. Can I use multiple ultrasonic sensors with one Arduino board? Yes, you can use multiple ultrasonic sensors with one Arduino board by connecting each sensor to a separate set of TRIG and ECHO pins. You can then modify the code to take readings from each sensor in sequence or simultaneously, depending on your requirements.

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