Interface and application programming (week12)

Group Assignment

Compare as many tool options as possible.

Link to Fab Academy 2020 assessment page

As I want to make music instrumental device in my final project, I tried to see the sound interface using python libraries that can make sounds from python codebase. Also, I checked OLED to display input values by bitmap-based graphical interface.

Sound Interface using python libraries

For making sound from MIDI input to audio output on Raspberry Pi, I run following command on Raspberry Pi :

    $ qjackctl &
    $ qsynth &

In detail, Raspberry Pi Tips - Fluidsynth

Generate audio files

Generate sine, sawtooth and square wave by numpy and scipy libraries.

python-rtmidi

Search "Synth" output port and play midi file

Mido

  • Environment: Rpi 3B, python 3.5.3 / 3.7.0
  • pip install mido python-rtmidi

MIDI note-on and note-off by Mido

Load MIDI file and check the length of music

Ref:

Pygame

  • Environment: Rpi 3B, python 3.5.3 / 3.7.0
  • pip install pygame

List output ports

GUI keyboard - display piano and send MIDI message

MIDI keyboard

Pretty_midi

  • Environment: Rpi 3B, python 3.5.3 (I could not install pretty-midi to virtual env of python3.7.0 )
git clone https://github.com/craffel/pretty-midi
cd pretty-midi
python3 setup.py install

Make MIDI file of noteon and noteoff of "G4"

Load MIDI file

Ref:

Graphical Interface using OLED

Display bitmap over I2C

OLED display

0.96 inches 128x64 dots OLED display

  • Maker: SUNHOKEY Electronics Co.,Ltd.
  • Vcc voltage: 3~5.5V
  • Control protocol: I2C
  • Microchip: SSD1306
  • Resolution: 128x64 dot
  • Color of charactor: white
  • I2C address(default) 0x3C

Datasheet

I used software libraries to display the values from input devices

For using above libraries, I made a simple exampleas follows. I commented some important points in program to use above libraries on megaTinyCore(AVR 1-serires).

IC2.OLED.SSD1306.01.ino

      #include 
      #include 
      #include 
      
      #define SCREEN_WIDTH 128 // OLED display width, in pixels
      #define SCREEN_HEIGHT 64 // OLED display height, in pixels
      
      #define OLED_RESET     -1 // Reset pin # (or -1 if sharing Arduino reset pin)
      
      Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);
      
      void setup() {
        // https://github.com/SpenceKonde/megaTinyCore
        // set the pins for SCL:PA2(15) and SDA:PA1(14) on ATtiny3216
        // default is swap(0) that means SCL:PB0(9) and SDA:PB1(8)
        Wire.swap(1);
        // I2C address for OLED device is 0x78 (01111000)
        // after shift 1 bit, 00111100 is 0x3C
        display.begin(SSD1306_SWITCHCAPVCC, 0x3C);
      }
      
      void loop() {
        display.clearDisplay();
      
        display.setTextSize(2);
        display.setTextColor(WHITE);
        display.setCursor(0, 10);
      
        display.println("Hello");
        display.println("ATTiny3216");
      
        display.display();
      
        delay(1000);
      }

Test code to display value from input board to OLED over I2C

For my final project, I want to display the value that I selected by tactile switches.

Test code for displaying value from tactile switches controlled by ATtiny3216 input board is:

final_Input_brd_v0.30_i2c.ino

Graphics

For displaying the note mark of "♪", I created a graphics by 15x16(height x width) pixels.

The hight and pixel match with the size of text and row of OLED.

Reference

Weekly Assignment