How to make music not interfere with the refresh rate of my lcd?

yazn8 · October 21, 2023, 2:17am

right now im making a sort of space invaders knock off at the moment its just displaying values however, i want to add music but when i do the music makes the lcd refresh with every note of the music.
heres the code:

#include <Wire.h>
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 2, 1, 0, 4, 5, 6, 7);

const uint8_t charBitmap[][8] = {
  { 0x8, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0 },
  { 0x1c, 0x8, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0 },
  { 0xe, 0x1c, 0x8, 0x0, 0x0, 0x0, 0x0, 0x0 },
  { 0xf, 0xe, 0x1c, 0x8, 0x0, 0x0, 0x0, 0x0 },
  { 0xe, 0xf, 0xe, 0x1c, 0x8, 0x0, 0x0, 0x0 },
  { 0x1c, 0xe, 0xf, 0xe, 0x1c, 0x8, 0x0, 0x0 },
  { 0x8, 0x1c, 0xe, 0xf, 0xe, 0x1c, 0x8, 0x0 },
  { 0x0, 0x8, 0x1c, 0xe, 0xf, 0xe, 0x1c, 0x8 }
};

#define NOTE_B0  31
#define NOTE_C1  33
#define NOTE_CS1 35
#define NOTE_D1  37
#define NOTE_DS1 39
#define NOTE_E1  41
#define NOTE_F1  44
#define NOTE_FS1 46
#define NOTE_G1  49
#define NOTE_GS1 52
#define NOTE_A1  55
#define NOTE_AS1 58
#define NOTE_B1  62
#define NOTE_C2  65
#define NOTE_CS2 69
#define NOTE_D2  73
#define NOTE_DS2 78
#define NOTE_E2  82
#define NOTE_F2  87
#define NOTE_FS2 93
#define NOTE_G2  98
#define NOTE_GS2 104
#define NOTE_A2  110
#define NOTE_AS2 117
#define NOTE_B2  123
#define NOTE_C3  131
#define NOTE_CS3 139
#define NOTE_D3  147
#define NOTE_DS3 156
#define NOTE_E3  165
#define NOTE_F3  175
#define NOTE_FS3 185
#define NOTE_G3  196
#define NOTE_GS3 208
#define NOTE_A3  220
#define NOTE_AS3 233
#define NOTE_B3  247
#define NOTE_C4  262
#define NOTE_CS4 277
#define NOTE_D4  294
#define NOTE_DS4 311
#define NOTE_E4  330
#define NOTE_F4  349
#define NOTE_FS4 370
#define NOTE_G4  392
#define NOTE_GS4 415
#define NOTE_A4  440
#define NOTE_AS4 466
#define NOTE_B4  494
#define NOTE_C5  523
#define NOTE_CS5 554
#define NOTE_D5  587
#define NOTE_DS5 622
#define NOTE_E5  659
#define NOTE_F5  698
#define NOTE_FS5 740
#define NOTE_G5  784
#define NOTE_GS5 831
#define NOTE_A5  880
#define NOTE_AS5 932
#define NOTE_B5  988
#define NOTE_C6  1047
#define NOTE_CS6 1109
#define NOTE_D6  1175
#define NOTE_DS6 1245
#define NOTE_E6  1319
#define NOTE_F6  1397
#define NOTE_FS6 1480
#define NOTE_G6  1568
#define NOTE_GS6 1661
#define NOTE_A6  1760
#define NOTE_AS6 1865
#define NOTE_B6  1976
#define NOTE_C7  2093
#define NOTE_CS7 2217
#define NOTE_D7  2349
#define NOTE_DS7 2489
#define NOTE_E7  2637
#define NOTE_F7  2794
#define NOTE_FS7 2960
#define NOTE_G7  3136
#define NOTE_GS7 3322
#define NOTE_A7  3520
#define NOTE_AS7 3729
#define NOTE_B7  3951
#define NOTE_C8  4186
#define NOTE_CS8 4435
#define NOTE_D8  4699
#define NOTE_DS8 4978
#define REST 0

int tempo=144; 

int buzzer = 3;

int melody[] = {

  NOTE_E5, 4,  NOTE_B4,8,  NOTE_C5,8,  NOTE_D5,4,  NOTE_C5,8,  NOTE_B4,8,
  NOTE_A4, 4,  NOTE_A4,8,  NOTE_C5,8,  NOTE_E5,4,  NOTE_D5,8,  NOTE_C5,8,
  NOTE_B4, -4,  NOTE_C5,8,  NOTE_D5,4,  NOTE_E5,4,
  NOTE_C5, 4,  NOTE_A4,4,  NOTE_A4,8,  NOTE_A4,4,  NOTE_B4,8,  NOTE_C5,8,

  NOTE_D5, -4,  NOTE_F5,8,  NOTE_A5,4,  NOTE_G5,8,  NOTE_F5,8,
  NOTE_E5, -4,  NOTE_C5,8,  NOTE_E5,4,  NOTE_D5,8,  NOTE_C5,8,
  NOTE_B4, 4,  NOTE_B4,8,  NOTE_C5,8,  NOTE_D5,4,  NOTE_E5,4,
  NOTE_C5, 4,  NOTE_A4,4,  NOTE_A4,4, REST, 4,

  NOTE_E5, 4,  NOTE_B4,8,  NOTE_C5,8,  NOTE_D5,4,  NOTE_C5,8,  NOTE_B4,8,
  NOTE_A4, 4,  NOTE_A4,8,  NOTE_C5,8,  NOTE_E5,4,  NOTE_D5,8,  NOTE_C5,8,
  NOTE_B4, -4,  NOTE_C5,8,  NOTE_D5,4,  NOTE_E5,4,
  NOTE_C5, 4,  NOTE_A4,4,  NOTE_A4,8,  NOTE_A4,4,  NOTE_B4,8,  NOTE_C5,8,

  NOTE_D5, -4,  NOTE_F5,8,  NOTE_A5,4,  NOTE_G5,8,  NOTE_F5,8,
  NOTE_E5, -4,  NOTE_C5,8,  NOTE_E5,4,  NOTE_D5,8,  NOTE_C5,8,
  NOTE_B4, 4,  NOTE_B4,8,  NOTE_C5,8,  NOTE_D5,4,  NOTE_E5,4,
  NOTE_C5, 4,  NOTE_A4,4,  NOTE_A4,4, REST, 4,
  

  NOTE_E5,2,  NOTE_C5,2,
  NOTE_D5,2,   NOTE_B4,2,
  NOTE_C5,2,   NOTE_A4,2,
  NOTE_GS4,2,  NOTE_B4,4,  REST,8, 
  NOTE_E5,2,   NOTE_C5,2,
  NOTE_D5,2,   NOTE_B4,2,
  NOTE_C5,4,   NOTE_E5,4,  NOTE_A5,2,
  NOTE_GS5,2,

};

int notes=sizeof(melody)/sizeof(melody[0])/2; 
int wholenote = (60000 * 4) / tempo;
int divider = 0, noteDuration = 0;

void setup(){
    int charBitmapSize = (sizeof(charBitmap) / sizeof(charBitmap[1]));

lcd.begin(16, 2);
lcd.setBacklightPin(3, POSITIVE);
lcd.setBacklight(HIGH);

for (int i = 0; i < charBitmapSize; i++) {
  lcd.createChar(i, (uint8_t *)charBitmap[i]);
}

lcd.home();
lcd.print("Hi world!");
lcd.setCursor(0, 1);
for (int i = 0; i < 8; i++)
  lcd.print(char(i));

delay(2000);
lcd.clear();
lcd.home();
lcd.print("loading[       ]");
lcd.setCursor(0, 0);
delay(100);
lcd.setCursor(8, 0);
lcd.print(char(255));
lcd.print(char(255));
delay(400);
lcd.print(char(255));
lcd.print(char(255));
lcd.print(char(255));
lcd.print(char(255));
delay(400);
lcd.print(char(255));
lcd.setCursor(0, 0);
delay(300);
lcd.print("finished.       ");
delay(500);
lcd.clear();
};

void loop() {
  musik();
  lcd.home();
  lcd.clear();
  int aim = analogRead(A3) / 100;
  int aim2 = analogRead(A3) / 2;
  int button = analogRead(A2) / 1000;
  int row = aim / 5;
  lcd.print(char(aim));
  lcd.print("   ");
  lcd.print(char(aim2));
  lcd.setCursor(0, 1);
  lcd.print(aim);
  lcd.print("   ");
  lcd.print(aim2);
  lcd.setCursor(9, row);
  lcd.print(row);
  lcd.print(" ");
  lcd.print(button);
};
void musik() {
    for (int thisNote = 0; thisNote < notes * 2; thisNote = thisNote + 2) {
    divider = melody[thisNote + 1];
    if (divider > 0) {
      noteDuration = (wholenote) / divider;
    } else if (divider < 0) {
      noteDuration = (wholenote) / abs(divider);
      noteDuration *= 1.5;
    }
    tone(buzzer, melody[thisNote], noteDuration*0.9);
    delay(noteDuration);
    noTone(buzzer);
  };
}

Paul_KD7HB · October 21, 2023, 2:21am

Did no one show you that a "for" loop is blocking until the ending test is true?

groundFungus · October 21, 2023, 2:29am

How often do you really need to update the LCD. More than 3 or 4 times a second seems excessive. Even better, only update the display when the data changes.

The LCD home() and clear() functions are really slow and calling both is redundant.

lastchancename · October 21, 2023, 2:40am

Since you’re controlling the music, not a module or library, the obvious answer along with the above, is to ditch the delays in favour of millis timing.

It’ll ne a rethink and a bit of work, but will free your code up to do other things.
The tone() function may help too.

yazn8 · October 21, 2023, 1:50pm

in more detail i want the refresh rate to be stable and make it refresh 4 times per second because its a game but i couldnt figure it out

groundFungus · October 21, 2023, 2:29pm

Here is a sketch to illustrate using the millis() timer to periodically update the LCD in a non-blocking manner. I use the hc44780 library because it is the best available at this time. The library is available to install using the IDE library manager.

This code has been tested on real hardware and is known to function.

Note that I do not use home() or clear() in loop(). I use spaces to overwrite old data, it is much faster than clear(). And labels are only printed once. Only data that changes is printed each update.

#include <Wire.h>
#include <hd44780.h>                       // main hd44780 header
#include <hd44780ioClass/hd44780_I2Cexp.h> // i2c expander i/o class header

hd44780_I2Cexp lcd; // declare lcd object: auto locate & auto config expander chip

// LCD geometry
const int LCD_COLS = 16;
const int LCD_ROWS = 2;


void setup()
{
   Serial.begin(115200);
   lcd.begin(LCD_COLS, LCD_ROWS);
   lcd.clear();
   lcd.print("Hello World");
   lcd.setCursor(0, 1);
   lcd.print("Millis ");
}

void loop()
{
  static unsigned long lcdTimer = 0;
  unsigned long lcdInterval = 250;
  if(millis() - lcdTimer >= lcdInterval)
  {
    lcdTimer = millis();
    updateLCD();
  }
}

void updateLCD()
{
  lcd.setCursor(7,1);
  lcd.print("         "); // overwrite old data with spaces
  lcd.setCursor(7,1);
  lcd.print(millis());
}

Non-blocking timing tutorials:
Blink without delay().
Blink without delay detailed explanation
Beginner's guide to millis().
Several things at a time.

You will need to use non-blocking code in the player parts to be able to display regularly. That means no for loops.

yazn8 · October 21, 2023, 7:42pm

Thanks so much! ill try to apply this to my code

system · April 18, 2024, 7:43pm

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How to make music not interfere with the refresh rate of my lcd?

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