家里門鈴壞了一個多月了，一直沒有時間去搞，過年前幾天剛好有點時間，拆出來看看發現由于電池漏液造成了電路板多處被腐蝕，修也是麻煩了，所以索性就自己重新設計一個出來。這個門鈴從電路設計，程序設計，調試及焊接都是我自己一手一腳完成，前后一共大概用了2天半時間。做出來的效果還是不錯的。大家有興趣可以試一下。
為了使門鈴更有個性化，我采用的是單片機，用單片機來產生所需要的響聲。其電路原理是控制單片機的IO口產生適當頻率的方波，經過三極管放大后驅動自藕變壓器的一次測，這時在變壓器的二次測會產生相同頻率的高壓方波從而使壓電陶瓷片發生形變，發出較大的門鈴聲。電源使用的是4節干電池，共6V，單片機電源是6V電源通過二極管降壓0.7V后提供。
程序的原理就是通過控制單片機的計時器T1和T2來產生不同頻率的PWM波，然后通過定義一個歌曲的數組，來控制不同音調，音高，音長，音高，音長。以下是曲譜的儲存格式：
曲譜存貯格式 unsigned char code MusicName{音高，音長，音高，音長...., 0,0};    末尾:0,0 表示結束(Important)
 
 音高由三位數字組成：
             個位是表示 1~7 這七個音符
             十位是表示音符所在的音區:1-低音，2-中音，3-高音;
             百位表示這個音符是否要升半音: 0-不升，1-升半音。
 
 音長最多由三位數字組成：
             個位表示音符的時值，其對應關系是：
                    |數值(n):  |0 |1 |2 |3 | 4 | 5 | 6
                    |幾分音符: |1 |2 |4 |8 |16 |32 |64          音符=2^n
             十位表示音符的演奏效果(0-2):  0-普通，1-連音，2-頓音
             百位是符點位: 0-無符點，1-有符點
 
 調用演奏子程序的格式
             Play(樂曲名,調號,升降八度,演奏速度);
       |樂曲名           : 要播放的樂曲指針,結尾以(0,0)結束;
       |調號(0-11)       :      是指樂曲升多少個半音演奏;
       |升降八度(1-3)        : 1:降八度, 2:不升不降, 3:升八度;
       |演奏速度(1-12000):     值越大速度越快;
 
由于門鈴在沒有按下時候CPU是沒有工作任務的，所以在沒有按下門鈴時，我令CPU進入休眠狀態，這樣能夠省下不少的電，使電池的工作壽命延長。當有人按下門鈴時，就會產生外部中斷INT0，使CPU退出休眠狀態，進入全速運行狀態，當歌曲演奏完畢，重新自動進入休眠狀態。下面是主程序和中斷服務程序
void main()
{
       IT0=1; //外中斷跳變產生中斷
       EX0=1;
       EA=1; //打開總中斷
       InitialSound();
       PCON |= 0x01;
       while(1)
       {
            
              if(Play_music==1)
              {
                     P1_7=0;
                     Play(Music_happynewyear,0,3,360);
                     P1_7=1;
                     Delay1ms(1500);
                     P1_7=0;
                     Play(Music_yingchun,0,3,360);
                     P1_7=1;
                     Play_music=0;
                     PCON |= 0x01;
              }
       }
}
 
void int0() interrupt 0 using 1
{
       PCON &=~ 0x00;
       Play_music=1;
}
 用單片機做音樂門鈴AT89C2051 DOOR BELL

 
                                                                           電路原理圖
 
由于當時快要過年了，所以我編了一首“新年好”和“迎春花”應一下節，其實所有歌都可以寫，只要有樂譜就可以，這樣你就可以把自己喜歡的歌編成程序燒入芯片，打造個性化的音樂門鈴。下面我給出一些歌的編碼，由于2051里面的flash容量有限，通常只能裝下2首歌，所以如果想換歌時又要自己重新把代碼替換燒入芯片。
//新年好
unsigned char code Music_happynewyear[]={ 0x15,0x03, 0x15,0x03, 0x15,0x02, 0x0F,0x02, 0x17,0x03,0x17,0x03, 0x17,0x02, 0x15,0x02, 0x15,0x03, 0x17,0x03,0x19,0x02,0x19,0x02, 0x18,0x03,0x17,0x03,0x16,0x01,0x16,0x03,0x17,0x03,0x18,0x02,0x18,0x02,0x17,0x03,0x16,0x03, 0x17,0x02, 0x15,0x02, 0x15,0x03, 0x17,0x03, 0x16,0x02, 0x0F,0x02, 0x11,0x03, 0x16,0x03, 0x15,0x01, 0x00,0x00 };
//迎春花
unsigned char code Music_yingchun[]={ 0x1F,0x03, 0x1F,0x04, 0x1A,0x04, 0x20,0x04, 0x1F,0x04, 0x1A,0x03, 0x19,0x03, 0x19,0x04, 0x17,0x04, 0x1A,0x04, 0x19,0x04, 0x17,0x03, 0x20,0x04, 0x1F,0x04, 0x1B,0x04, 0x1A,0x04, 0x19,0x04, 0x18,0x04, 0x17,0x04, 0x16,0x04,
0x15,0x03, 0x17,0x04, 0x19,0x04, 0x1A,0x04, 0x1A,0x04,0x1A,0x04, 0x1A,0x04, 0x1A,0x03, 0x19,0x03, 0x1A,0x03,0x19,0x03, 0x1A,0x03, 0x1F,0x03, 0x1A,0x03, 0x19,0x03, 0x19,0x03, 0x17,0x02, 0x16,0x03, 0x17,0x01, 0x17,0x67, 0x19,0x04, 0x1A,0x03, 0x1F,0x03, 0x19,0x02, 0x19,0x03, 0x17,0x03, 0x16,0x67, 0x17,0x04, 0x16,0x03, 0x15,0x03,0x15,0x03, 0x10,0x02, 0x0F,0x03,0x10,0x01,0x10,0x01,0x17,0x03,0x19,0x03,0x17,0x67,0x16,0x04,0x17,0x03,0x19,0x03, 0x17,0x67, 0x16,0x04, 0x17,0x03, 0x19,0x03,0x19,0x03, 0x10,0x03, 0x15,0x01, 0x17,0x03, 0x1F,0x03, 0x1A,0x67, 0x19,0x04, 0x17,0x03, 0x1F,0x03, 0x1A,0x67, 0x19,0x04, 0x1F,0x67, 0x1F,0x04, 0x20,0x04, 0x1F,0x04, 0x1A,0x03, 0x19,0x01, 0x19,0x03, 0x1A,0x03, 0x19,0x03, 0x17,0x04, 0x16,0x04, 0x19,0x03, 0x10,0x03, 0x15,0x17, 0x1F,0x03, 0x1F,0x02, 0x1A,0x04, 0x19,0x04, 0x1A,0x03, 0x1F,0x03, 0x17,0x17, 0x17,0x67, 0x19,0x04, 0x1A,0x03,0x1F,0x03, 0x19,0x02, 0x19,0x67, 0x17,0x04, 0x16,0x67,0x17,0x04, 0x16,0x03, 0x15,0x03, 0x15,0x03, 0x10,0x02, 0x0F,0x03, 0x10,0x01, 0x00,0x00 };
//揮著翅膀的女孩
unsigned char code Music_Girl[]={ 0x17,0x02, 0x17,0x03, 0x18,0x03, 0x19,0x02, 0x15,0x03,
0x16,0x03, 0x17,0x03, 0x17,0x03, 0x17,0x03, 0x18,0x03,0x19,0x02, 0x16,0x03, 0x17,0x03, 0x18,0x02, 0x18,0x03, 0x17,0x03, 0x15,0x02, 0x18,0x03, 0x17,0x03, 0x18,0x02,0x10,0x03, 0x15,0x03, 0x16,0x02, 0x15,0x03, 0x16,0x03,0x17,0x02, 0x17,0x03, 0x18,0x03, 0x19,0x02, 0x1A,0x03, 0x1B,0x03, 0x1F,0x03, 0x1F,0x03, 0x17,0x03, 0x18,0x03,0x19,0x02, 0x16,0x03, 0x17,0x03, 0x18,0x03, 0x17,0x03, 0x18,0x03, 0x1F,0x03, 0x1F,0x02, 0x16,0x03, 0x17,0x03, 0x18,0x03, 0x17,0x03, 0x18,0x03, 0x20,0x03, 0x20,0x02, 0x1F,0x03, 0x1B,0x03, 0x1F,0x66, 0x20,0x03, 0x21,0x03, 0x20,0x03, 0x1F,0x03, 0x1B,0x03, 0x1F,0x66, 0x1F,0x03, 0x1B,0x03, 0x19,0x03, 0x19,0x03, 0x15,0x03, 0x1A,0x66, 0x1A,0x03, 0x19,0x03, 0x15,0x03, 0x15,0x03, 0x17,0x03, 0x16,0x66, 0x17,0x04, 0x18,0x04, 0x18,0x03, 0x19,0x03,0x1F,0x03, 0x1B,0x03, 0x1F,0x66,0x20,0x03,0x21,0x03,0x20,0x03,0x1F,0x03,0x1B,0x03,0x1F,0x66,0x1F,0x03,0x1B,0x03, 0x19,0x03, 0x19,0x03, 0x15,0x03, 0x1A,0x66,0x1A,0x03, 0x19,0x03, 0x19,0x03, 0x1F,0x03, 0x1B,0x03, 0x1F,0x00, 0x1A,0x03, 0x1A,0x03, 0x1A,0x03, 0x1B,0x03,0x1B,0x03, 0x1A,0x03, 0x19,0x03, 0x19,0x02, 0x17,0x03,0x15,0x17, 0x15,0x03, 0x16,0x03, 0x17,0x03, 0x18,0x03,
0x17,0x04, 0x18,0x0E, 0x18,0x03, 0x17,0x04, 0x18,0x0E,0x18,0x66, 0x17,0x03, 0x18,0x03, 0x17,0x03, 0x18,0x03, 0x20,0x03, 0x20,0x02, 0x1F,0x03, 0x1B,0x03, 0x1F,0x66,0x20,0x03, 0x21,0x03, 0x20,0x03, 0x1F,0x03, 0x1B,0x03,0x1F,0x66, 0x1F,0x04, 0x1B,0x0E, 0x1B,0x03, 0x19,0x03,0x19,0x03, 0x15,0x03, 0x1A,0x66, 0x1A,0x03, 0x19,0x03, 0x15,0x03, 0x15,0x03, 0x17,0x03,0x16,0x66,0x17,0x04,0x18,0x04,0x18,0x03,0x19,0x03,0x1F,0x03,0x1B,0x03,0x1F,0x66, 0x20,0x03, 0x21,0x03, 0x20,0x03, 0x1F,0x03, 0x1B,0x03, 0x1F,0x66, 0x1F,0x03, 0x1B,0x03, 0x19,0x03, 0x19,0x03, 0x15,0x03, 0x1A,0x66, 0x1A,0x03, 0x19,0x03, 0x19,0x03, 0x1F,0x03, 0x1B,0x03, 0x1F,0x00, 0x18,0x02, 0x18,0x03, 0x1A,0x03, 0x19,0x0D, 0x15,0x03, 0x15,0x02,0x18,0x66, 0x16,0x02, 0x17,0x02, 0x15,0x00, 0x00,0x00};
//同一首歌
unsigned char code Music_Same[]={ 0x0F,0x01, 0x15,0x02, 0x16,0x02, 0x17,0x66, 0x18,0x03,
0x17,0x02, 0x15,0x02, 0x16,0x01, 0x15,0x02, 0x10,0x02,0x15,0x00, 0x0F,0x01, 0x15,0x02, 0x16,0x02, 0x17,0x02, 0x17,0x03, 0x18,0x03, 0x19,0x02, 0x15,0x02, 0x18,0x66, 0x17,0x03, 0x19,0x02, 0x16,0x03, 0x17,0x03, 0x16,0x00, 0x17,0x01, 0x19,0x02, 0x1B,0x02, 0x1B,0x70, 0x1A,0x03, 0x1A,0x01, 0x19,0x02, 0x19,0x03, 0x1A,0x03, 0x1B,0x02, 0x1A,0x0D, 0x19,0x03, 0x17,0x00,0x18,0x66,0x18,0x03,0x19,0x02,0x1A,0x02,0x19,0x0C,0x18,0x0D,0x17,0x03,0x16,0x01, 0x11,0x02, 0x11,0x03, 0x10,0x03, 0x0F,0x0C,0x10,0x02, 0x15,0x00, 0x1F,0x01, 0x1A,0x01, 0x18,0x66, 0x19,0x03, 0x1A,0x01, 0x1B,0x02, 0x1B,0x03, 0x1B,0x03,0x1B,0x0C, 0x1A,0x0D, 0x19,0x03,0x17,0x00,0x1F,0x01,0x1A,0x01,0x18,0x66,0x19,0x03,0x1A,0x01,0x10,0x02,0x10,0x03, 0x10,0x03, 0x1A,0x0C, 0x18,0x0D, 0x17,0x03,0x16,0x00, 0x0F,0x01, 0x15,0x02, 0x16,0x02, 0x17,0x70, 0x18,0x03, 0x17,0x02, 0x15,0x03, 0x15,0x03, 0x16,0x66, 0x16,0x03, 0x16,0x02, 0x16,0x03, 0x15,0x03, 0x10,0x02, 0x10,0x01, 0x11,0x01, 0x11,0x66, 0x10,0x03, 0x0F,0x0C, 0x1A,0x02, 0x19,0x02, 0x16,0x03, 0x16,0x03, 0x18,0x66,0x18,0x03, 0x18,0x02, 0x17,0x03, 0x16,0x03, 0x19,0x00, 0x00,0x00 };        
//兩只蝴蝶                                
unsigned char code Music_Two[] ={ 0x17,0x03, 0x16,0x03, 0x17,0x01, 0x16,0x03, 0x17,0x03,
0x16,0x03, 0x15,0x01, 0x10,0x03, 0x15,0x03, 0x16,0x02, 0x16,0x0D, 0x17,0x03, 0x16,0x03, 0x15,0x03, 0x10,0x03, 0x10,0x0E, 0x15,0x04, 0x0F,0x01, 0x17,0x03, 0x16,0x03,0x17,0x01, 0x16,0x03, 0x17,0x03, 0x16,0x03, 0x15,0x01, 0x10,0x03, 0x15,0x03, 0x16,0x02, 0x16,0x0D, 0x17,0x03, 0x16,0x03, 0x15,0x03, 0x10,0x03, 0x15,0x03, 0x16,0x01, 0x17,0x03, 0x16,0x03, 0x17,0x01, 0x16,0x03, 0x17,0x03, 0x16,0x03, 0x15,0x01, 0x10,0x03, 0x15,0x03, 0x16,0x02, 0x16,0x0D, 0x17,0x03, 0x16,0x03, 0x15,0x03, 0x10,0x03, 0x10,0x0E, 0x15,0x04, 0x0F,0x01, 0x17,0x03, 0x19,0x03, 0x19,0x01, 0x19,0x03, 0x1A,0x03, 0x19,0x03, 0x17,0x01, 0x16,0x03, 0x16,0x03, 0x16,0x02, 0x16,0x0D, 0x17,0x03, 0x16,0x03, 0x15,0x03, 0x10,0x03, 0x10,0x0D, 0x15,0x00, 0x19,0x03, 0x19,0x03, 0x1A,0x03, 0x1F,0x03, 0x1B,0x03, 0x1B,0x03, 0x1A,0x03, 0x17,0x0D,0x16,0x03,0x16,0x03,0x16,0x0D,0x17,0x01,0x17,0x03,0x17,0x03,0x19,0x03,0x1A,0x02,0x1A,0x02,0x10,0x03, 0x17,0x0D, 0x16,0x03, 0x16,0x01, 0x17,0x03, 0x19,0x03, 0x19,0x03, 0x17,0x03, 0x19,0x02, 0x1F,0x02, 0x1B,0x03, 0x1A,0x03, 0x1A,0x0E, 0x1B,0x04, 0x17,0x02, 0x1A,0x03, 0x1A,0x03, 0x1A,0x0E, 0x1B,0x04, 0x1A,0x03, 0x19,0x03, 0x17,0x03, 0x16,0x03,
0x17,0x0D, 0x16,0x03, 0x17,0x03, 0x19,0x01, 0x19,0x03, 0x19,0x03, 0x1A,0x03, 0x1F,0x03, 0x1B,0x03, 0x1B,0x03, 0x1A,0x03, 0x17,0x0D, 0x16,0x03, 0x16,0x03, 0x16,0x03, 0x17,0x01, 0x17,0x03, 0x17,0x03, 0x19,0x03, 0x1A,0x02, 0x1A,0x02, 0x10,0x03, 0x17,0x0D, 0x16,0x03, 0x16,0x01, 0x17,0x03, 0x19,0x03, 0x19,0x03, 0x17,0x03, 0x19,0x03, 0x1F,0x02, 0x1B,0x03, 0x1A,0x03, 0x1A,0x0E, 0x1B,0x04, 0x17,0x02, 0x1A,0x03, 0x1A,0x03, 0x1A,0x0E, 0x1B,0x04,
0x17,0x16, 0x1A,0x03, 0x1A,0x03, 0x1A,0x0E, 0x1B,0x04, 0x1A,0x03, 0x19,0x03, 0x17,0x03, 0x16,0x03, 0x0F,0x02, 0x10,0x03, 0x15,0x00, 0x00,0x00 };