A Digital Piano built with PIC18 MCU
This is a final group project of EE2004 - Microcomputer Systems at City University of Hong Kong, contributed by KUAN-TING KUO and TSUNG-YU CHEN.
Because of our loves of music we decided to build a digital piano by a PIC18 development kit.
There are mainly three features of our design.
First, we use 4x4 bottoms, instead of just using the more basic 8 buttons, as the keys of the piano. The 4x4 buttons are connected to 8 pin output, therefore, we use time multiplexing to check which pin is being pressed. The keys cover two completed octaves, a play button and a clear button, which is used in the third function.
The second function is the note display in the 7-segment LED. By keeping track of which button is pressed, we can find out what note is played and show the corresponding note on the LED. The LED display not only occurs when the button is pressed, but it is also turned on when the recorded music is being played so that the people can know what notes are pressed.
The third function is music recording and playing. Every time when music is played, the buttons that are pressed are recorded. When the play button is pressed, the speaker will output the music. The same music can be played out several times by pressing the play button. When we want to clear the previous record of the music and start to record a new song, we can press the 'clear button' to delete all the previous record and start a new one.
Figure 1: System Architecture
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Input:
a. 4x4 Button: connected to PORTC
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Output:
a. Play Music: PORTB
b. 7-segment LED: PORTD
Figure 2: Flow Chart of Main and Setup
Figure 3: Flow Chart of GetNote
Figure 4: Flow Chart of GetFreq, Lookup7Seg and PlaySound
Figure 5: Flow Chart of PlayRecord and Pause