基于51单片机的简易电子琴，能利用所给键盘的1，2，3，4，5，6，7，8八个键，能够发出7个不同的音调，而且有一个按键可以自动播放歌曲，要求按键按下时发声，松开延时一小段时间，中间再按别的键则发另外一音调的声音，当系统扫描到键盘按下，则快速检测出是哪一个按键被按下，然后单片机的定时器启动，发出一定频率的脉冲，该频率的脉冲经喇叭驱动电路放大滤波后，就会发出相应的音调。如果在前一个按下的键发声的同时有另一个按键被按下，则启动中断系统。前面的发音停止，转到后按的键的发音程序。发出后按的键的音调。-51 simple microcontroller-based keyboard that can use the keyboard to 1,2,3,4,5,6,7,8 eight keys can be issued seven different tones, and there is a button to automatically play songs, requirements sound when the button is pressed, release delay for a short time, in the middle and then another key to send another tone sounds when the system scans the keyboard is pressed, then quickly detect which key is pressed, then the microcontroller The timer is started, a certain frequency of the pulse is issued, the frequency of the pulse through the speaker driver circuit amplifies the filtered, it will send the appropriate tone. If the previous key pressed while another sound button is pressed, then starts the interrupt system. Stop in front of the pronunciation, the pronunciation keys to press procedures. Issued press the key tone.