/*
 Joginder
 hobbyprojects
 28-07-2020 
 Vibration_based_LED_POV_Display.ino
*/
  #define Delay 1000
  
  int sensor_pin = 8;
  int input_state;
  int val;
  int LED = 13;
  unsigned long n = 0;   
      
void setup()
{
    DDRD = 0xFF;
    pinMode(sensor_pin, INPUT_PULLUP);
    pinMode(LED,OUTPUT); 
    
    TIMSK2 = (TIMSK2 & B11111110) | 0x01;
    TCCR2B = (TCCR2B & B11111000) | 0x02;  
}
void loop()
{ 
    input_state = digitalRead(sensor_pin);
    while (input_state == HIGH)
  {
    input_state = digitalRead(sensor_pin);    
  }

  delay2();  
  //delay2(); 
  //delay2(); 
    
 // display "ABC"

  // letter 'A'
        PORTD = 0x3f;   // column data
        delay1();       // LED pixel width
        PORTD = 0x00;
        delay1();       // gap between columns
        PORTD = 0x44;
        delay1();
        PORTD = 0x00;
        delay1();
        PORTD = 0x44;
        delay1();
        PORTD = 0x00;
        delay1();
        PORTD = 0x44;
        delay1();
        PORTD = 0x00;
        delay1();
        PORTD = 0x3f;
        delay1();
        PORTD = 0x00;
        delay1();
  
        delay2();       // gap between letters

  // letter 'B'
        PORTD = 0x7f;
        delay1();   
        PORTD = 0x00;
        delay1();   
        PORTD = 0x49;
        delay1();   
        PORTD = 0x00;
        delay1();   
        PORTD = 0x49;
        delay1();   
        PORTD = 0x00;
        delay1();   
        PORTD = 0x49;
        delay1();   
        PORTD = 0x00;
        delay1();   
        PORTD = 0x36;
        delay1();   
        PORTD = 0x00;       
        delay1();

        delay2();

  // letter 'C'
        PORTD = 0x3e;
        delay1();   
        PORTD = 0x00;
        delay1();   
        PORTD = 0x41;
        delay1();   
        PORTD = 0x00;
        delay1();   
        PORTD = 0x41;
        delay1();   
        PORTD = 0x00;
        delay1();   
        PORTD = 0x41;
        delay1();   
        PORTD = 0x00;
        delay1();   
        PORTD = 0x22;
        delay1();   
        PORTD = 0x00;
        delay1();  

    input_state = digitalRead(sensor_pin);
    while (input_state == LOW)
  {
    val = analogRead(A0);
    if(val < 50)
    val = 50;    
    input_state = digitalRead(sensor_pin);    
  }

}

void delay1()
{
  delayMicroseconds(Delay); 
}

void delay2()
{
  delayMicroseconds(Delay*3); 
}

   ISR(TIMER2_OVF_vect)
{
  n++;
  if(n >= val)
  {
   n = 0;
   digitalWrite(LED, !digitalRead(LED));
  }
}