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Sound Alarm (Buzzer) | NexaLearn IoT Lab | NexaLearn

Output & Alerts15 دقيقة

Sound Alarm (Buzzer)

Generating warning tones with the tone() function.

Lesson Content

Buzzers come in two types: Active (emits a fixed sound when you supply 5V) and Passive (requires a PWM signal at different frequencies to produce tones). For musical tones or graded alarm sounds, we use a Passive Buzzer with the tone(pin, frequency) function, which sets the frequency in Hz.

Components Needed

Arduino UnoPassive Buzzerمقاومة 100 أوم

Wiring Notes

Connect the positive leg to a PWM-capable pin (like pin 9) through a small resistor to protect the pin, and the negative leg to GND.

Code Example

const int buzzerPin = 9;
void setup() {
  pinMode(buzzerPin, OUTPUT);
}
void loop() {
  tone(buzzerPin, 1000); // 1000 Hz
  delay(500);
  tone(buzzerPin, 2000); // 2000 Hz
  delay(500);
  noTone(buzzerPin);
  delay(1000);
}

Common Mistakes

Using an Active Buzzer with the tone() function — the sound will be very distorted because an Active Buzzer has its own internal oscillator.

Next Lesson

Stepper Motors (Precise Millimeter Control)