Arduino UNO R4 - Ultrasonic Sensor - Piezo Buzzer
We'll learn how to control a piezo buzler using Arduino UNO R4 and an ultrasonic sensor.
- When the object is near the ultrasonic sensor, emit a sound.
- When the object is away from the ultrasonic sensor, stop the sound.
- When the object is near the ultrasonic sensor, play a song melody.
Hardware Preparation
Or you can buy the following sensor kits:
| 1 | × | DIYables Sensor Kit (30 sensors/displays) | |
| 1 | × | DIYables Sensor Kit (18 sensors/displays) |
Disclosure: Some of the links provided in this section are Amazon affiliate links. We may receive a commission for any purchases made through these links at no additional cost to you.
Additionally, some of these links are for products from our own brand, DIYables .
Additionally, some of these links are for products from our own brand, DIYables .
Overview of Piezo Buzzer and Ultrasonic Sensor
Learn about piezo buzzers and ultrasonic sensors, including their pinouts, functions, and programming, in the tutorials provided.
This guide uses a buzzer that requires 3-5V, but you can also modify it for a 12V buzzer. Learn more about this in the Arduino UNO R4 - Buzzer tutorial.
Wiring Diagram
- The wiring diagram between Arduino UNO R4, ultrasonic sensor, and piezo buzzer
This image is created using Fritzing. Click to enlarge image
- The wiring diagram between Arduino UNO R4, ultrasonic sensor, and piezo buzzer module
This image is created using Fritzing. Click to enlarge image
See The best way to supply power to the Arduino Uno R4 and other components.
Arduino UNO R4 Code - Simple Sound
/*
* This Arduino UNO R4 code was developed by newbiely.com
*
* This Arduino UNO R4 code is made available for public use without any restriction
*
* For comprehensive instructions and wiring diagrams, please visit:
* https://newbiely.com/tutorials/arduino-uno-r4/arduino-uno-r4-ultrasonic-sensor-piezo-buzzer
*/
#define TRIG_PIN 6 // The Arduino UNO R4 pin connected to the ultrasonic sensor's TRIG pin
#define ECHO_PIN 7 // The Arduino UNO R4 pin connected to the ultrasonic sensor's ECHO pin
#define BUZZER_PIN 3 // The Arduino UNO R4 pin connected to Piezo Buzzer's pin
#define DISTANCE_THRESHOLD 50 // centimeters
float duration_us, distance_cm;
void setup() {
Serial.begin (9600); // initialize serial port
pinMode(TRIG_PIN, OUTPUT); // set arduino pin to output mode
pinMode(ECHO_PIN, INPUT); // set arduino pin to input mode
pinMode(BUZZER_PIN, OUTPUT); // set arduino pin to output mode
}
void loop() {
// generate 10-microsecond pulse to TRIG pin
digitalWrite(TRIG_PIN, HIGH);
delayMicroseconds(10);
digitalWrite(TRIG_PIN, LOW);
// measure duration of pulse from ECHO pin
duration_us = pulseIn(ECHO_PIN, HIGH);
// calculate the distance
distance_cm = 0.017 * duration_us;
if(distance_cm < DISTANCE_THRESHOLD)
digitalWrite(BUZZER_PIN, HIGH); // turn on Piezo Buzzer
else
digitalWrite(BUZZER_PIN, LOW); // turn off Piezo Buzzer
// print the value to Serial Monitor
Serial.print("distance: ");
Serial.print(distance_cm);
Serial.println(" cm");
delay(500);
}
Detailed Instructions
Follow these instructions step by step:
- If this is your first time using the Arduino Uno R4 WiFi/Minima, refer to the tutorial on setting up the environment for Arduino Uno R4 WiFi/Minima in the Arduino IDE.
- Wire the components according to the provided diagram.
- Connect the Arduino Uno R4 board to your computer using a USB cable.
- Launch the Arduino IDE on your computer.
- Select the appropriate Arduino Uno R4 board (e.g., Arduino Uno R4 WiFi) and COM port.
- Copy and paste the above code into the Arduino IDE
- Press the Upload button in the Arduino IDE to transfer the code to the Arduino UNO R4
- Wave your hand near the sensor
- Hear the sound from the piezo buzzer
Code Explanation
Look at the comment lines in the source code for a step-by-step explanation!
Arduino UNO R4 Code - Melody
/*
* This Arduino UNO R4 code was developed by newbiely.com
*
* This Arduino UNO R4 code is made available for public use without any restriction
*
* For comprehensive instructions and wiring diagrams, please visit:
* https://newbiely.com/tutorials/arduino-uno-r4/arduino-uno-r4-ultrasonic-sensor-piezo-buzzer
*/
#include "pitches.h"
#define TRIG_PIN 6 // The Arduino UNO R4 pin connected to the ultrasonic sensor's TRIG pin
#define ECHO_PIN 7 // The Arduino UNO R4 pin connected to the ultrasonic sensor's ECHO pin
#define BUZZER_PIN 3 // The Arduino UNO R4 pin connected to Piezo Buzzer's pin
#define DISTANCE_THRESHOLD 50 // centimeters
float duration_us, distance_cm;
// notes in the melody:
int melody[] = {
NOTE_E5, NOTE_E5, NOTE_E5,
NOTE_E5, NOTE_E5, NOTE_E5,
NOTE_E5, NOTE_G5, NOTE_C5, NOTE_D5,
NOTE_E5,
NOTE_F5, NOTE_F5, NOTE_F5, NOTE_F5,
NOTE_F5, NOTE_E5, NOTE_E5, NOTE_E5, NOTE_E5,
NOTE_E5, NOTE_D5, NOTE_D5, NOTE_E5,
NOTE_D5, NOTE_G5
};
// note durations: 4 = quarter note, 8 = eighth note, etc, also called tempo:
int noteDurations[] = {
8, 8, 4,
8, 8, 4,
8, 8, 8, 8,
2,
8, 8, 8, 8,
8, 8, 8, 16, 16,
8, 8, 8, 8,
4, 4
};
void setup() {
pinMode(TRIG_PIN, OUTPUT); // set arduino pin to output mode
pinMode(ECHO_PIN, INPUT); // set arduino pin to input mode
}
void loop() {
// generate 10-microsecond pulse to TRIG pin
digitalWrite(TRIG_PIN, HIGH);
delayMicroseconds(10);
digitalWrite(TRIG_PIN, LOW);
// measure duration of pulse from ECHO pin
duration_us = pulseIn(ECHO_PIN, HIGH);
// calculate the distance
distance_cm = 0.017 * duration_us;
if(distance_cm < DISTANCE_THRESHOLD)
buzzer(); // play a song
delay(500);
}
void buzzer() {
// iterate over the notes of the melody:
int size = sizeof(noteDurations) / sizeof(int);
for (int thisNote = 0; thisNote < size; thisNote++) {
// to calculate the note duration, take one second divided by the note type.
//e.g. quarter note = 1000 / 4, eighth note = 1000/8, etc.
int noteDuration = 1000 / noteDurations[thisNote];
tone(BUZZER_PIN, melody[thisNote], noteDuration);
// to distinguish the notes, set a minimum time between them.
// the note's duration + 30% seems to work well:
int pauseBetweenNotes = noteDuration * 1.30;
delay(pauseBetweenNotes);
// stop the tone playing:
noTone(BUZZER_PIN);
}
}
Detailed Instructions
- Copy the code and open it using Arduino IDE.
- Make a file named pitches.h in Arduino IDE by:
- Clicking on the button below the serial monitor icon and selecting New Tab, or using the Ctrl+Shift+N keys.
- Provide the file name pitches.h and press the OK button.
- Copy the code below and paste it into the file named pitches.h you created.
- Press the Upload button in the Arduino IDE to send code to the Arduino UNO R4.
- Wave your hand near the sensor.
- Hear the melody from the piezo buzzer.
- The given code is for educational purposes. The ultrasonic sensor is very sensitive to noise. For practical uses of the ultrasonic sensor, you should apply noise filtering. Learn about how to filter noise for the ultrasonic sensor.
/*************************************************
* Public Constants
*************************************************/
#define NOTE_B0 31
#define NOTE_C1 33
#define NOTE_CS1 35
#define NOTE_D1 37
#define NOTE_DS1 39
#define NOTE_E1 41
#define NOTE_F1 44
#define NOTE_FS1 46
#define NOTE_G1 49
#define NOTE_GS1 52
#define NOTE_A1 55
#define NOTE_AS1 58
#define NOTE_B1 62
#define NOTE_C2 65
#define NOTE_CS2 69
#define NOTE_D2 73
#define NOTE_DS2 78
#define NOTE_E2 82
#define NOTE_F2 87
#define NOTE_FS2 93
#define NOTE_G2 98
#define NOTE_GS2 104
#define NOTE_A2 110
#define NOTE_AS2 117
#define NOTE_B2 123
#define NOTE_C3 131
#define NOTE_CS3 139
#define NOTE_D3 147
#define NOTE_DS3 156
#define NOTE_E3 165
#define NOTE_F3 175
#define NOTE_FS3 185
#define NOTE_G3 196
#define NOTE_GS3 208
#define NOTE_A3 220
#define NOTE_AS3 233
#define NOTE_B3 247
#define NOTE_C4 262
#define NOTE_CS4 277
#define NOTE_D4 294
#define NOTE_DS4 311
#define NOTE_E4 330
#define NOTE_F4 349
#define NOTE_FS4 370
#define NOTE_G4 392
#define NOTE_GS4 415
#define NOTE_A4 440
#define NOTE_AS4 466
#define NOTE_B4 494
#define NOTE_C5 523
#define NOTE_CS5 554
#define NOTE_D5 587
#define NOTE_DS5 622
#define NOTE_E5 659
#define NOTE_F5 698
#define NOTE_FS5 740
#define NOTE_G5 784
#define NOTE_GS5 831
#define NOTE_A5 880
#define NOTE_AS5 932
#define NOTE_B5 988
#define NOTE_C6 1047
#define NOTE_CS6 1109
#define NOTE_D6 1175
#define NOTE_DS6 1245
#define NOTE_E6 1319
#define NOTE_F6 1397
#define NOTE_FS6 1480
#define NOTE_G6 1568
#define NOTE_GS6 1661
#define NOTE_A6 1760
#define NOTE_AS6 1865
#define NOTE_B6 1976
#define NOTE_C7 2093
#define NOTE_CS7 2217
#define NOTE_D7 2349
#define NOTE_DS7 2489
#define NOTE_E7 2637
#define NOTE_F7 2794
#define NOTE_FS7 2960
#define NOTE_G7 3136
#define NOTE_GS7 3322
#define NOTE_A7 3520
#define NOTE_AS7 3729
#define NOTE_B7 3951
#define NOTE_C8 4186
#define NOTE_CS8 4435
#define NOTE_D8 4699
#define NOTE_DS8 4978
Code Explanation
Look at each explanation written in the comments within the source code!
※ NOTE THAT: