Arduino sketch: Pulse sensor by means of a photoresistor • Breathing sensor by means of resistance sensor fabric

pulsedetect_07.ino

//pins
const int led = 13; //calibration LED
const int vibrator = 12;
const int buzzer = 11;
const int pulseSensor = A0; //LDR
const int breathSensor = A1; //resistive fabric

//pulse sensor variables
int pulseMin = 1023;
int pulseMax = 0;
int pulse = 0;

//breath sensor variables
int breathBase = 0;
int breathMax = 0;
int breath = 0;

//timers
int calibration = 5000; //calibration time
int interval = 100; //sampling time
long previousMillis = 0;

int count = 1; //callibration loop
int once = 0;



void setup() {
  Serial.begin(9600);

  pinMode(vibrator, OUTPUT);
  pinMode(buzzer, OUTPUT);
  pinMode(led, OUTPUT);
}

void loop() {
  unsigned long currentMillis = millis();

  //START calibration
  while (millis() < calibration) {
    //breath sensor min & max
    pulse = analogRead(pulseSensor);

    if (pulse > pulseMax) {
      pulseMax = pulse;
    }
    if (pulse < pulseMin) {
      pulseMin = pulse;
    }
    
//    Serial.print(pulseMin);
//    Serial.print(" - ");
//    Serial.print(pulseMax);
//    Serial.print(" - ");
    Serial.println(pulse);

    //breath sensor min & max
    breath = analogRead(breathSensor);

    if (breath > breathMax) {
      breathMax = breath;
    }
      breathBase += breath;
      
//    Serial.println(breath);
    
    //notify the user that we are callibrating
    analogWrite(led, 100);
    
    delay(50);
    count++;
  } 
  
  if (once == 0) {
    breathBase = breathBase / count;
    analogWrite(led, 0);
    once = 1;
  }
  //END calibration


  //normalize execution time
  if (currentMillis - previousMillis > interval) {
    pulse = analogRead(pulseSensor);
    //normalize values
   pulse = map(pulse, pulseMin, pulseMax, 0, 255);
   pulse = constrain(pulse, 0, 255);



//    Serial.print(pulseMin);
//    Serial.print(" - ");
//    Serial.print(pulseMax);
//    Serial.print(" -- ");
    Serial.println(pulse);

    breath = analogRead(breathSensor);
    //normalize values
    breath = map(breath, breathBase, breathMax, 0, 255);
    breath = constrain(breath, 0, 255);
      
    if (pulse > 300) {
//      analogWrite(vibrator, pulse);
    }
    
    analogWrite(vibrator, breath);

//    Serial.print(breathBase);
//    Serial.print(" - ");
//    Serial.print(breathMax);
//    Serial.print(" -- ");
//    Serial.print(analogRead(breathSensor));
//    Serial.print(" -- ");    
//    Serial.println(breath);

    previousMillis = currentMillis;
  }
}