Description: 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.
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