exgpill.ino

volatile float signal=0;
float prev_signal=0;


void setup() {
  cli();                      //stop interrupts for till we make the settings
  TCCR1A = 0;                 // Reset entire TCCR1A to 0 
  TCCR1B = 0;                 // Reset entire TCCR1B to 0
  TCCR1B |= B00000011;        //Set CS12 to 1 so we get prescalar 64
  TIMSK1 |= B00000010;        //Set OCIE1A to 1 so we enable compare match A 
  OCR1A = 500;             //Finally we set compare register A to this value  
  sei(); 
  Serial.begin(9600);
}

void loop() {
  if(signal != prev_signal){
    Serial.println(signal);
    prev_signal= signal;
  }
}


ISR(TIMER1_COMPA_vect){
   TCNT1  = 0;  
  float sensor_value = analogRead(A0);
  float output = sensor_value;
  {
    static float z1, z2; // filter section state
    float x = output - 0.05159732*z1 - 0.36347401*z2;
    output = 0.01856301*x + 0.03712602*z1 + 0.01856301*z2;
    z2 = z1;
    z1 = x;
  }
  {
    static float z1, z2; // filter section state
    float x = output - -0.53945795*z1 - 0.39764934*z2;
    output = 1.00000000*x + -2.00000000*z1 + 1.00000000*z2;
    z2 = z1;
    z1 = x;
  }
  {
    static float z1, z2; // filter section state
    float x = output - 0.47319594*z1 - 0.70744137*z2;
    output = 1.00000000*x + 2.00000000*z1 + 1.00000000*z2;
    z2 = z1;
    z1 = x;
  }
  {
    static float z1, z2; // filter section state
    float x = output - -1.00211112*z1 - 0.74520226*z2;
    output = 1.00000000*x + -2.00000000*z1 + 1.00000000*z2;
    z2 = z1;
    z1 = x;
  }
  signal = output;
}