arduino-mixer/arduino-mixer.ino

#include <SPI.h>
#include <Adafruit_GFX.h>
#include <Adafruit_PCD8544.h>
#include <Fonts/Picopixel.h>
#include <Button.h>
#include <Encoder.h>

Adafruit_PCD8544 display = Adafruit_PCD8544(14, 15, 16, 17, 18);

Button button(4);
Encoder encoder(3, 2);

// General vars
unsigned long time;
boolean connected = false;
boolean dataReady = false;
boolean editing = false;
boolean blink = false;

// Encoder related vars
long position = 0;

// Serial related vars
const byte numChars = 32;
char receivedChars[numChars];
char tempChars[numChars];  

char command[numChars] = {0};

boolean newData = false;


// Set backlight
boolean light = 0;
int timeout = 10000;

void toggleBacklight(int value = 128) {
  if (light) {
    analogWrite(5, 0);
    light = 0;
  } else {
    analogWrite(5, value);
    light = 1;
  }
}

// Set variables for menu
int programLenght;
int currentProgram = 0;
char programName[numChars] = {0};
boolean menuUpdate = true;
float volume = -1;

// Draw screen
void drawMenu() {
  display.clearDisplay();
  display.setFont(&Picopixel);

  // Check for connection
  if (connected && dataReady)
  {
    // Draw top bar
    display.setCursor(0, 4);
    display.print((String)(currentProgram + 1) + "/" + (String)(programLenght));

    display.setCursor(73, 4);
    display.print("USB");
  }

  display.drawLine(0, 6, 84, 6, BLACK);
  display.setFont(NULL);

  // Check for connection
  if (connected && dataReady) {
    // Program name
    drawName();

    // Volume Bar
    drawBar();
  } else {
    // Blink connection message if not connected
    if (time % 500 == 0)
    {
      blink = (!blink) ? true : false;
    }

    if (!blink)
    {
      display.setCursor(9, 10);
      display.print("Waiting for");
      if (!connected)
      {
        display.setCursor(12, 18);
        display.print("Connection");
      } else if (!dataReady)
      {
        display.setCursor(30, 18);
        display.print("Data");
      }
    }
  }

  // Bottom Bar
  display.drawLine(0, 38, 84, 38, BLACK);
  if (connected && dataReady)
  {
    display.setCursor(0, 40);
    if (editing)
    {
      display.print(" -    OK    + ");
    } else {
      display.print(" <    OK    > ");
    }
  }

  display.display();
}

// Bar position
const int pos[2] = { 4, 26 };

// Draw volume bar and text
void drawBar() {
  // Set fonts and size
  display.setFont(&Picopixel);
  display.setCursor(4, pos[1] - 2);
  display.print("Volume:");

  // Blink percentage if editing
  if (editing && time % 500 == 0)
  {
    blink = (!blink) ? 1 : 0;
  }

  // Center percentage
  if (volume == 0) {
    display.setCursor(39, pos[1] - 2);
  } else if (volume == 100) {
    display.setCursor(36, pos[1] - 2);
  } else {
    display.setCursor(37, pos[1] - 2);
  }

  if (!blink)
  {
    display.print((String)round(volume) + "%");
  }

  // Draw volume bar
  display.drawRect(pos[0], pos[1], 76, 8, BLACK);
  display.drawLine(pos[0], pos[1] + 8, pos[0], pos[1] + 9, BLACK);
  display.drawPixel(pos[0] + (76 / 4) * 1 - 1, pos[1] + 8, BLACK);
  display.drawLine(pos[0] + (76 / 4) * 2 - 1, pos[1] + 8, pos[0] + (76 / 4) * 2 - 1, pos[1] + 9, BLACK);
  display.drawPixel(pos[0] + (76 / 4) * 3 - 1, pos[1] + 8, BLACK);
  display.drawLine(pos[0] + 75, pos[1] + 8, pos[0] + 75, pos[1] + 9, BLACK);

  display.fillRect(pos[0], pos[1], round(volume / 100 * 76), 8, BLACK);
  display.setFont(NULL);
}

// Draw program name in the middle of the display or scroll it
void drawName() {
  int width = 0;
  for (size_t i = 0; i < sizeof(programName); i++)
  {
    if (programName[i] != NULL)
    {
      width = width + 6;
    }
  }

  if (width > 84)
  {
    // TODO: Make the text scroll if the name is too long
  } else {
    int x = (84 / 2) - (width / 2);
    display.setCursor(x, 10);
  }
  display.print(programName);
}

void processData() {
    if (newData == true) {
        strcpy(tempChars, receivedChars);
        
        char * strtokIndx;

        strtokIndx = strtok(tempChars,",");
        strcpy(command, strtokIndx);
 
        strtokIndx = strtok(NULL, ",");

        if (strcmp("HELLO", command) == 0)
        {
          connected = true;
          Serial.println("<OK>");
          Serial.println("<COUNT>");
          Serial.println("<SWITCH," + (String)currentProgram + ">");
        } 
        else if (strcmp("COUNT", command) == 0)
        {
          programLenght = atoi(strtokIndx);
          Serial.println("<OK>");
        } 
        else if (strcmp("CURRENT", command) == 0)
        {
          currentProgram = atoi(strtokIndx);
          Serial.println("<OK>");
        } 
        else if (strcmp("NAME", command) == 0) 
        {
          strcpy(programName, strtokIndx);
          Serial.println("<OK>");
        } 
        else if (strcmp("GETVOL", command) == 0) 
        {
          volume = atoi(strtokIndx);
          Serial.println("<OK>");
        }

        newData = false;
        dataReady = true;
    }
}

void checkSerial() {
    static boolean recvInProgress = false;
    static byte ndx = 0;
    char startMarker = '<';
    char endMarker = '>';
    char rc;

    while (Serial.available() > 0 && newData == false) {
        rc = Serial.read();

        if (recvInProgress == true) {
            if (rc != endMarker) {
                receivedChars[ndx] = rc;
                ndx++;
                if (ndx >= numChars) {
                    ndx = numChars - 1;
                }
            }
            else {
                receivedChars[ndx] = '\0'; // terminate the string
                recvInProgress = false;
                ndx = 0;
                newData = true;
            }
        }

        else if (rc == startMarker) {
            recvInProgress = true;
        }
    }

    processData();
}

// Check for button input
// TODO: Improve encoder input
void checkInput(unsigned long time) {
  long newPosition = encoder.read();
  if (newPosition != position) {
    menuUpdate = true;
    if (newPosition < position - 3) // Rotating anti-clockwise
    {
      if (!editing)
      {
        if (currentProgram == 0)
        {
          currentProgram = programLenght - 1;
        } else {
          currentProgram--;
        }
        Serial.println("<SWITCH," + (String)currentProgram + ">");
      } else {
        if (volume != 0)
        {
          Serial.println("<SETVOL," + (String)(volume - 1) + ">");
        }
      }
      position = newPosition;
    }
    if (newPosition > position + 3) // Rotating clockwise
    {
      if (!editing)
      {
        if (currentProgram == programLenght - 1)
        {
          currentProgram = 0;
        } else {
          currentProgram++;
        }
        Serial.println("<SWITCH," + (String)currentProgram + ">");
      } else {
        if (volume != 100)
        {
          Serial.println("<SETVOL," + (String)(volume + 1) + ">");
        }
      }
      position = newPosition;
    }
  }

  if (button.pressed())
  {
    editing = (editing) ? 0 : 1;
  }
}

// Init arduino
void setup()   {
  // Start serial connection
  Serial.begin(115200);

  // Init button
  button.begin();

  // Init display
  display.begin();
  display.setContrast(50);
  toggleBacklight();
  display.clearDisplay();
  display.display();

  // TODO: Remove testing variables
  currentProgram = 0;
}

void loop() {
  // Check time
  time = millis();
  menuUpdate = (time % 1000 == 0) ? true : false;

  if (programLenght == 0 || volume == -1 || strcmp("", programName) == 0)
  {
    dataReady = false;
  }

  if (!editing && connected && dataReady)
  {
    blink = false;
  }
  
  

  // Check for serial data or commands
  checkSerial();

  // Check if serial connection is established
  if (connected && dataReady)
  {
    // Draw menu every second or every 0.1 second when editing
    if (menuUpdate || (editing && time % 100 == 0)) {
      menuUpdate = false;
      drawMenu();
    }

    // Check input
    checkInput(time);

  } else {
    if (menuUpdate)
    {
      // Draw menu with "Waiting for connection", name and volume are ignored bij drawMenu()
      menuUpdate = false;
      drawMenu();
    }
  }
}