5.3 Alarm System
5.3.1 PIR Motion Sensor
Open the 5.3.1PIR-Motion-Sensor code with Arduino IDE.
#define PyroelectricPIN 23
void setup() {
Serial.begin(9600);
pinMode(PyroelectricPIN,INPUT);
}
void loop() {
//Read the value of PIR motion sensor
int ReadValue = digitalRead(PyroelectricPIN);
if(ReadValue){
Serial.println("Someone");
}
else{
Serial.println("No one");
}
delay(100);
}
Choose the ESP32 Dev Module board and COM port, and upload the code.
Test Result:
When someone is in the area, Someone is displayed on the monitor, and the red LED on the sensor goes off. However, if there is no one, No one will be printed and the LED on the sensor will always be on.
Voltage: 3~5V
Current: 3.6mA
Power: 18mW
Angle of View: Y = 90°, X = 110° (Theoretical value)
Detection Distance: ≤5m
5.3.2 Passive Buzzer
Passive Buzzer cannot vibrate to emit sound itself, unless putting a square wave signal with a certain frequency. Moreover, the emitting sound varies due to the different frequency of square wave, so a passive buzzer can simulate tunes.
An analog squire wave can be generated by changing the power level at pins. For example, after the high level lasting for 500ms, it shifts to a low level for another 500ms then to a high level again…
We drive the buzzer via a squire wave within 200~5000Hz, and we can compute the frequency(f): f=1/T, T is theperiod (the total time of high and low level).
Parameters:
Voltage: 3~5V
Current: ≤5mA
Power: ≤25mW
Open the 5.3.2Passive-Buzzer code with Arduino IDE.
#define BuzzerPin 16 //Define the buzzer pin
void setup() {
//Set the pin to output mode
pinMode(BuzzerPin,OUTPUT);
}
void loop() {
digitalWrite(BuzzerPin,HIGH);
delayMicroseconds(500);//Delay 500us
digitalWrite(BuzzerPin,LOW);
delayMicroseconds(500);//Delay 500us
}
Choose the ESP32 Dev Module board and COM port, and upload the code.
Test Result:
Passive Buzzer keeps emitting sound.
5.3.3 Buzzer-Tone
Open the 5.3.3Buzzer-Tone code with Arduino IDE.
const int buzzerPin = 16; //Set buzzer pin to 16
void setup() {
ledcAttachChannel(buzzerPin,1000,8,4);
}
void loop() {
ledcWriteTone(buzzerPin,532); //duo --C2
delay(100);
ledcWriteTone(buzzerPin,587); //re --D3
delay(100);
ledcWriteTone(buzzerPin,659); //mi --E3
delay(100);
//Alarm
for(int i = 200; i<=1000; i+=10){
ledcWriteTone(buzzerPin,i);
delay(10);
}
//Alarm
for(int i = 1000; i>=200; i-=10){
ledcWriteTone(buzzerPin,i);
delay(10);
}
ledcWriteTone(buzzerPin,0);
}
Choose the ESP32 Dev Module board and COM port, and upload the code.
Test Result:
Buzzer alarms vialedcWriteTone() function.
ledcWriteTone() generates PWM signal with a certain frequency to drive the buzzer to vibrate, and the duration and tone is controlled by related parameters.
The ledcWriteTone() function needs to be used in conjunction with the ledcAttachChannel() function
ledcAttachChannel
This function is used to set duty for the LEDC channel.
bool ledcWriteChannel(uint8_t channel, uint32_t duty);
channelselect LEDC channel.dutyselect duty to be set for selected LEDC channel.
This function will return true if setting duty is successful. If false is returned, error occurs and duty was not set.
ledcWriteTone
This function is used to setup the LEDC pin to 50 % PWM tone on selected frequency.
uint32_t ledcWriteTone(uint8_t pin, uint32_t freq);
pinselect LEDC pin.freqselect frequency of pwm signal. If frequency is0, duty will be set to 0.
This function will return frequency set for LEDC pin. If 0 is returned, error occurs and LEDC pin was not configured.
5.4 Buzzer-Music
Open the 5.3.4Buzzer-Music code with Arduino IDE
#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
#define BUZZERPIN 16
// notes in the melody:
int melody[] = {
NOTE_E4, NOTE_E4, NOTE_E4, NOTE_C4, NOTE_E4, NOTE_G4, NOTE_G3,
NOTE_C4, NOTE_G3, NOTE_E3, NOTE_A3, NOTE_B3, NOTE_AS3, NOTE_A3, NOTE_G3, NOTE_E4, NOTE_G4, NOTE_A4, NOTE_F4, NOTE_G4, NOTE_E4, NOTE_C4, NOTE_D4, NOTE_B3,
NOTE_C4, NOTE_G3, NOTE_E3, NOTE_A3, NOTE_B3, NOTE_AS3, NOTE_A3, NOTE_G3, NOTE_E4, NOTE_G4, NOTE_A4, NOTE_F4, NOTE_G4, NOTE_E4, NOTE_C4, NOTE_D4, NOTE_B3,
NOTE_G4, NOTE_FS4, NOTE_E4, NOTE_DS4, NOTE_E4, NOTE_GS3, NOTE_A3, NOTE_C4, NOTE_A3, NOTE_C4, NOTE_D4, NOTE_G4, NOTE_FS4, NOTE_E4, NOTE_DS4, NOTE_E4, NOTE_C5, NOTE_C5, NOTE_C5,
NOTE_G4, NOTE_FS4, NOTE_E4, NOTE_DS4, NOTE_E4, NOTE_GS3, NOTE_A3, NOTE_C4, NOTE_A3, NOTE_C4, NOTE_D4, NOTE_DS4, NOTE_D4, NOTE_C4,
NOTE_C4, NOTE_C4, NOTE_C4, NOTE_C4, NOTE_D4, NOTE_E4, NOTE_C4, NOTE_A3, NOTE_G3, NOTE_C4, NOTE_C4, NOTE_C4, NOTE_C4, NOTE_D4, NOTE_E4,
NOTE_C4, NOTE_C4, NOTE_C4, NOTE_C4, NOTE_D4, NOTE_E4, NOTE_C4, NOTE_A3, NOTE_G3
};
// note durations: 4 = quarter note, 8 = eighth note, etc.:
int noteDurations[] = {
8,4,4,8,4,2,2,
3,3,3,4,4,8,4,8,8,8,4,8,4,3,8,8,3,
3,3,3,4,4,8,4,8,8,8,4,8,4,3,8,8,2,
8,8,8,4,4,8,8,4,8,8,3,8,8,8,4,4,4,8,2,
8,8,8,4,4,8,8,4,8,8,3,3,3,1,
8,4,4,8,4,8,4,8,2,8,4,4,8,4,1,
8,4,4,8,4,8,4,8,2
};
void setup() {
ledcAttachChannel(BUZZERPIN,1000,8,4);
// iterate over the notes of the melody:
for (int thisNote = 0; thisNote < 98; 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];
ledcWriteTone(BUZZERPIN, melody[thisNote]);
delayMicroseconds(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
ledcWriteTone(BUZZERPIN,0);
}
}
void loop() {
// no need to repeat the melody.
}
Choose the ESP32 Dev Module board and COM port, and upload the code.
Test Result:
The buzzer will play music.
5.3.5 Alarm System
Open the 5.3.5Alarm-System code with Arduino IDE
#define BuzzerPin 16 //Set buzzer pin to 16
#define PyroelectricPIN 23 //Set PIR mition sensor to 23
#define Led 27 //Set led pin to 27
void setup() {
Serial.begin(9600);
//Set the pins modes
pinMode(PyroelectricPIN,INPUT);
pinMode(Led,OUTPUT);
ledcAttachChannel(BuzzerPin,1000,8,4);
}
void loop() {
//Read the value of PIR motion sensor
int ReadValue = digitalRead(PyroelectricPIN);
if(ReadValue){
Serial.println("Someone");
digitalWrite(Led,HIGH);
//Alarm
for(int i = 200; i<=1000; i+=10){
ledcWriteTone(BuzzerPin,i);
delay(10);
}
digitalWrite(Led,LOW);
//Alarm
for(int i = 1000; i>=200; i-=10){
ledcWriteTone(BuzzerPin,i);
delay(10);
}
}
//Stop alarming
ledcWriteTone(BuzzerPin,0);
Serial.println("No one");
}
Choose the ESP32 Dev Module board and COM port, and upload the code.
Test Result:
When the sensor detects a motion, buzzer emits sound and LED blinks to remind of an invasion.
