Arduino Nano - Motion Sensor - Piezo Buzzer

This tutorial instructs you how to use Arduino Nano and motion sensor to control piezo buzzer to generate sound when detecting the movement of human or animal. In detail:

This can be applied in an automation process that triggers actions upon detecting human presence.

Hardware Preparation

1×Arduino Nano
1×USB A to Mini-B USB cable
1×HC-SR501 Motion Sensor
1×Piezo Buzzer
1×Breadboard
1×Jumper Wires
1×(Optional) 9V Power Adapter for Arduino Nano
1×(Recommended) Screw Terminal Adapter for Arduino Nano

Or you can buy the following sensor kit:

1×DIYables Sensor Kit 30 types, 69 units
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Overview of Piezo Buzzer and Motion Sensor

If you are unfamiliar with piezo buzzer and motion sensor (including pinout, operation, and programming), the following tutorials can help:

Wiring Diagram

The wiring diagram between Arduino Nano and Motion Sensor Piezo Buzzer

This image is created using Fritzing. Click to enlarge image

Initial Setting

Time Delay AdjusterScrew it in anti-clockwise direction fully.
Detection Range AdjusterScrew it in clockwise direction fully.
Repeat Trigger SelectorPut jumper as shown on the image.
arduino motion sensor initial setting

Arduino Nano Code - Simple Sound

/* * This Arduino Nano code was developed by newbiely.com * * This Arduino Nano code is made available for public use without any restriction * * For comprehensive instructions and wiring diagrams, please visit: * https://newbiely.com/tutorials/arduino-nano/arduino-nano-motion-sensor-piezo-buzzer */ #define MOTION_SENSOR_PIN 2 // The Arduino Nano pin connected to the OUTPUT pin of motion sensor #define BUZZER_PIN 7 // The Arduino Nano pin connected to the piezo buzzer int motion_state = LOW; // current state of motion sensor's pin int prev_motion_state = LOW; // previous state of motion sensor's pin void setup() { Serial.begin(9600); // Initialize the Serial to communicate with the Serial Monitor. pinMode(MOTION_SENSOR_PIN, INPUT); // set arduino pin to input mode pinMode(BUZZER_PIN, OUTPUT); // set arduino pin to output mode } void loop() { prev_motion_state = motion_state; // store old state motion_state = digitalRead(MOTION_SENSOR_PIN); // read new state if (prev_motion_state == LOW && motion_state == HIGH) { // pin state change: LOW -> HIGH Serial.println("Motion detected!"); digitalWrite(BUZZER_PIN, HIGH); // turn on } else if (prev_motion_state == HIGH && motion_state == LOW) { // pin state change: HIGH -> LOW Serial.println("Motion stopped!"); digitalWrite(BUZZER_PIN, LOW); // turn off } }

Detailed Instructions

  • Plug the USB cable into both the Arduino Nano and the PC.
  • Launch the Arduino IDE, select the correct board and port.
  • Paste the code into the IDE and open it.
  • Click the Upload button in the IDE to transfer the code to the Arduino Nano.
  • Wave your hand in front of the sensor.
  • Listen to the sound of the piezo buzzer.

Code Explanation

Check out the line-by-line explanation contained in the comments of the source code!

Arduino Nano Code - Melody

/* * This Arduino Nano code was developed by newbiely.com * * This Arduino Nano code is made available for public use without any restriction * * For comprehensive instructions and wiring diagrams, please visit: * https://newbiely.com/tutorials/arduino-nano/arduino-nano-motion-sensor-piezo-buzzer */ #include "pitches.h" #define MOTION_SENSOR_PIN 2 // The Arduino Nano pin connected to the OUTPUT pin of motion sensor #define BUZZER_PIN 7 // The Arduino Nano pin connected to the piezo buzzer // 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() { Serial.begin(9600); // Initialize the Serial to communicate with the Serial Monitor. pinMode(MOTION_SENSOR_PIN, INPUT); // set arduino pin to input mode } void loop() { int motionState = digitalRead(MOTION_SENSOR_PIN); // read new state if (motionState == HIGH) { Serial.println("The motion is detected"); buzzer(); } } 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 with the Arduino IDE.
  • Create the pitches.h file On Arduino IDE by:
    • Either click on the button just below the serial monitor icon and choose New Tab, or use Ctrl+Shift+N keys.
    Arduino IDE 2 adds file
    • Give file's name pitches.h and click OK button
    Arduino IDE 2 adds file pitches.h
    • Copy the below code and paste it to the created pitches.h file.
    /************************************************* * 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
    • Click the Upload button on the Arduino IDE to compile and upload the code to the Arduino Nano.
    • Move your hand in front of the sensor.
    • Listen to the tune played by the piezo buzzer.

    Code Explanation

    **Read the line-by-line explanation in comment lines of the source code!**. Check out the line-by-line description in the comments of the source code!

    ※ NOTE THAT:

    The code above utilizes the delay() function. This has the effect of blocking other code during the playing of the melody. To prevent this from happening, the ezBuzzer library can be used instead. This library is designed to allow the buzzer to beep or play a melody without blocking other code.

Video Tutorial