2.1 Buzzer Alert Patterns

Time to add sound to our projects! An active buzzer is like an electronic horn that makes sound when powered. Unlike LEDs that you see, buzzers let you hear your project’s status - perfect for alarms, notifications, and alerts.

Active buzzers are “plug and play” - just send power and they beep! We’ll create different alert patterns: standard alerts, SOS emergency signals, quick warnings, and alarm sounds.

Component List

• Raspberry Pi Pico W x1

• 830 Tie-Points Breadboard x1

• Transistor S8050 x1

• Resistor 1KΩ x1

• Active Buzzer x1

• Jumper Wire Several

Component knowledge

transistor

Buzzer

Why use a transistor with the buzzer?

Power Amplification: - Buzzer needs more current than Pico can safely provide - Transistor acts as a “current amplifier” - small signal controls big current - Result: MUCH louder sound than direct connection

Protection: The 1KΩ resistor protects both the transistor and Pico from overcurrent.

Connect

Two types of buzzers are included in the kit. We need to use active buzzer. Turn them around, the sealed back (not the exposed PCB) is the one we want.

The buzzer needs to use a transistor when working, here we use S8050 (NPN Transistor).

Code

Note

• Open the 2.1_buzzer_alert_patterns.py file under the path of Ultimate-Starter-Kit-for-Pico-W\Python\1.Project or copy this code into Thonny, then click “Run Current Script” or simply press F5 to run it.

• Don’t forget to click on the “MicroPython (Raspberry Pi Pico)” interpreter in the bottom right corner.

After running the code, listen to the different alert patterns! You’ll hear 4 distinct sounds cycling every few seconds: Standard Alert (4 short beeps), SOS Signal (morse code … — …), Quick Warning (rapid beeps), and Alarm Sound (alternating tones). Perfect for learning different notification patterns!

The following is the program code:

"""
Buzzer Alert System

Creates different alert patterns using a buzzer.
Demonstrates various beeping patterns for different situations.
"""

import machine
import utime

# Pin and timing constants
BUZZER_PIN = 15                     # buzzer connected to pin 15
PATTERN_DELAY = 2000                # delay between different patterns
TOTAL_PATTERNS = 4                  # number of alert patterns

# Alert pattern settings
SHORT_BEEP = 200                    # short beep duration
LONG_BEEP = 600                     # long beep duration
QUICK_PAUSE = 100                   # short pause between beeps
MEDIUM_PAUSE = 400                  # medium pause between beeps

# Initialize buzzer
buzzer = machine.Pin(BUZZER_PIN, machine.Pin.OUT)

def beep(duration):
    """Generate a beep for specified duration"""
    buzzer.value(1)
    utime.sleep_ms(duration)
    buzzer.value(0)

def pause(duration):
    """Create a pause for specified duration"""
    utime.sleep_ms(duration)

def standard_alert():
    """Pattern 1: Standard alert - 4 short beeps"""
    for i in range(4):
        beep(SHORT_BEEP)
        pause(MEDIUM_PAUSE)

def sos_signal():
    """Pattern 2: SOS signal - 3 short, 3 long, 3 short"""
    # Three short beeps (S)
    for i in range(3):
        beep(SHORT_BEEP)
        pause(QUICK_PAUSE)

    pause(MEDIUM_PAUSE)

    # Three long beeps (O)
    for i in range(3):
        beep(LONG_BEEP)
        pause(QUICK_PAUSE)

    pause(MEDIUM_PAUSE)

    # Three short beeps (S)
    for i in range(3):
        beep(SHORT_BEEP)
        pause(QUICK_PAUSE)

def quick_warning():
    """Pattern 3: Quick warning - 6 rapid beeps"""
    for i in range(6):
        beep(SHORT_BEEP // 2)  # very short beeps
        pause(QUICK_PAUSE)

def alarm_sound():
    """Pattern 4: Alarm sound - alternating short and long beeps"""
    for i in range(3):
        # Short beep
        beep(SHORT_BEEP)
        pause(QUICK_PAUSE)

        # Long beep
        beep(LONG_BEEP)
        pause(QUICK_PAUSE)

def setup():
    """Initialize the buzzer alert system"""
    print("=== Buzzer Alert System ===")
    print("Demonstrating different alert patterns:")
    print("1. Standard Alert  2. SOS Signal")
    print("3. Quick Warning   4. Alarm Sound")
    print()

def main():
    """Main function"""
    setup()

    try:
        cycle_count = 0
        while True:
            cycle_count += 1
            print(f"--- Alert Cycle #{cycle_count} ---")

            # Pattern 1: Standard Alert (4 short beeps)
            print("Pattern 1: Standard Alert")
            standard_alert()
            pause(PATTERN_DELAY)

            # Pattern 2: SOS Signal (... --- ...)
            print("Pattern 2: SOS Emergency Signal")
            sos_signal()
            pause(PATTERN_DELAY)

            # Pattern 3: Quick Warning (rapid beeps)
            print("Pattern 3: Quick Warning")
            quick_warning()
            pause(PATTERN_DELAY)

            # Pattern 4: Alarm Sound (alternating tones)
            print("Pattern 4: Alarm Sound")
            alarm_sound()
            pause(PATTERN_DELAY)

            print("--- Cycle Complete ---")
            print()

    except KeyboardInterrupt:
        print("\nBuzzer alert system stopped.")
        print(f"Total cycles completed: {cycle_count}")

        # Turn off buzzer safely
        buzzer.value(0)
        print("Buzzer turned off.")

if __name__ == "__main__":
    main()

Phenomenon