gistfile1.c

#include <LiquidCrystal.h>

LiquidCrystal lcd(12, 11, 5, 4, 3, 2);
int offset = 0;
int sinetable[32];
 
// Precomputed sine table taken from somewhere...
// can't find it now
void setupSintable() {
  sinetable[0] = 127;
   sinetable[1] = 152;
   sinetable[2] = 176;
   sinetable[3] = 198;
   sinetable[4]=217;
   sinetable[5]=233;
   sinetable[6]=245;
   sinetable[7]=252;
   sinetable[8]=254;
   sinetable[9]=252;
   sinetable[10]=245;
   sinetable[11]=233;
   sinetable[12]=217;
   sinetable[13]=198;
   sinetable[14]=176;
   sinetable[15]=152;
   sinetable[16]=128;
   sinetable[17]=103;
   sinetable[18]=79;
   sinetable[19]=57;
   sinetable[20]=38;
   sinetable[21]=22;
   sinetable[22]=10;
   sinetable[23]=3;
   sinetable[24]=0;
   sinetable[25]=3;
   sinetable[26]=10;
   sinetable[27]=22;
   sinetable[28]=38;
   sinetable[29]=57;
   sinetable[30]=79;
   sinetable[31]=103;
}

/**
* Set up the custom characters used for waveform
* display.
*/
byte bar1[8] = {
  B00000,
  B00000,
  B00000,
  B00000,
  
  B00000,
  B00000,
  B00000,
  B11111,
};
byte bar2[8] = {
  B00000,
  B00000,
  B00000,
  B00000,
  
  B00000,
  B00000,
  B11111,
  B00000,
};
byte bar3[8] = {
  B00000,
  B00000,
  B00000,
  B00000,
  
  B00000,
  B11111,
  B00000,
  B00000,
};
byte bar4[8] = {
  B00000,
  B00000,
  B00000,
  B00000,

  B11111,  
  B00000,
  B00000,
  B00000,
};
byte bar5[8] = {
  B00000,
  B00000,
  B00000,
  B11111,
  
  B00000,
  B00000,
  B00000,
  B00000,

};
byte bar6[8] = {
  B00000,
  B00000,
  B11111,
  B00000,
  
  B00000,
  B00000,
  B00000,
  B00000,

};
byte bar7[8] = {
  B00000,
  B11111,
  B00000,
  B00000,
  
  B00000,
  B00000,
  B00000,
  B00000,
};
byte bar8[8] = {
  B11111,
  B00000,
  B00000,
  B00000,
  
  B00000,
  B00000,
  B00000,
  B00000,

};

// values 0-15, pos 0-15
void plotValue( int val, int pos ) {
  if( val < 8 ) {
    lcd.setCursor( pos, 1 );
    lcd.write( val );
    lcd.setCursor( pos, 0 );
    lcd.write( ' ' );
  }
  else {
    lcd.setCursor( pos, 0 );
    lcd.write( val - 8 );
    lcd.setCursor( pos, 1 );
    lcd.write( ' ' );
  }
}

void createCustomChars() {
  lcd.createChar(0, bar1);
  lcd.createChar(1, bar2);
  lcd.createChar(2, bar3);
  lcd.createChar(3, bar4);
  lcd.createChar(4, bar5);
  lcd.createChar(5, bar6);
  lcd.createChar(6, bar7);
  lcd.createChar(7, bar8);
}

void drawSin( int offset ) {
  for( int x=0; x<16; x++ ) {
    int val = sinetable[(2*x+offset)%32]/16;
    plotValue( val, x );
  }  
}

void setup() {
  setupSintable();
  createCustomChars();
  lcd.begin(16, 2);
}

void loop() {
  drawSin( offset );
  offset+=1;
}