树莓派pico播放小星星，无源蜂鸣器

from machine import Pin, PWM
import time

# ================= 配置区域 =================
BUZZER_PIN = 15       # 蜂鸣器连接的 GPIO 引脚 (建议 GP15)
VOLUME = 20000        # 音量 (0-65535), 建议 40000 (约 60%)
BPM = 80              # 速度 (每分钟拍数), 儿歌建议 60-90
BASE_TEMPO = 60000 // BPM  # 计算每拍的毫秒数 (约 750ms)
# ===========================================

# 初始化 PWM
buzzer = PWM(Pin(BUZZER_PIN))
buzzer.duty_u16(VOLUME)

# 音符频率表 (C 大调)
# 对应简谱：1=C, 2=D, 3=E, 4=F, 5=G, 6=A
NOTES = {
    'C4': 261, 'D4': 293, 'E4': 329, 'F4': 349, 'G4': 392, 'A4': 440,
    'C5': 523,  # 高音 C
    '0': 0      # 休止符
}

# 小星星 旋律数据
# 格式：(音符，节拍数)
# 节拍数：1 = 一拍，2 = 两拍 (结尾音)
SONG = [
    # 1 1 5 5 6 6 5 - (一闪一闪亮晶晶)
    ('C4', 1), ('C4', 1), ('G4', 1), ('G4', 1), ('A4', 1), ('A4', 1), ('G4', 2),
    
    # 4 4 3 3 2 2 1 - (满天都是小星星)
    ('F4', 1), ('F4', 1), ('E4', 1), ('E4', 1), ('D4', 1), ('D4', 1), ('C4', 2),
    
    # 5 5 4 4 3 3 2 - (挂在天上放光明)
    ('G4', 1), ('G4', 1), ('F4', 1), ('F4', 1), ('E4', 1), ('E4', 1), ('D4', 2),
    
    # 5 5 4 4 3 3 2 - (好像许多小眼睛)
    ('G4', 1), ('G4', 1), ('F4', 1), ('F4', 1), ('E4', 1), ('E4', 1), ('D4', 2),
    
    # 1 1 5 5 6 6 5 - (一闪一闪亮晶晶)
    ('C4', 1), ('C4', 1), ('G4', 1), ('G4', 1), ('A4', 1), ('A4', 1), ('G4', 2),
    
    # 4 4 3 3 2 2 1 - (满天都是小星星)
    ('F4', 1), ('F4', 1), ('E4', 1), ('E4', 1), ('D4', 1), ('D4', 1), ('C4', 2),
]

def play_note(note, beats):
    """播放单个音符"""
    freq = NOTES.get(note, 0)
    
    if freq == 0:
        # 休止符：静音
        buzzer.duty_u16(0)
    else:
        # 发声：设置频率和音量
        buzzer.freq(freq)
        buzzer.duty_u16(VOLUME)
    
    # 计算持续时间 (毫秒)
    duration = int(BASE_TEMPO * beats)
    time.sleep_ms(duration)
    
    # 音符间短暂停顿，让旋律更清晰 (约 30ms)
    buzzer.duty_u16(0)
    time.sleep_ms(30)

try:
    print("开始播放：小星星...")
    print(f"速度：{BPM} BPM | 引脚：GP{BUZZER_PIN}")
    
    while True:
        for note, beats in SONG:
            play_note(note, beats)
        
        print("一曲完毕，2 秒后重复...")
        time.sleep(2)

except KeyboardInterrupt:
    print("用户停止播放。")

finally:
    # 程序彻底退出时才关闭蜂鸣器
    buzzer.deinit()
    print("蜂鸣器已关闭。")