Substituir sensor de pulsação por potenciómetro - Arduino

volatile int rate[10];                           // used to hold last ten IBI values
volatile unsigned long sampleCounter = 0;                // used to determine pulse timing
volatile unsigned long lastBeatTime = 0;                 // used to find the inter beat interval
volatile int P =512;                                     // used to find peak in pulse wave
volatile int T = 512;                                    // used to find trough in pulse wave
volatile int thresh = 512;                       // used to find instant moment of heart beat
volatile int amp = 100;                          // used to hold amplitude of pulse waveform
volatile boolean firstBeat = true;       // used to seed rate array so we startup with reasonable BPM
volatile boolean secondBeat = true;      // used to seed rate array so we startup with reasonable BPM
int pulsePin = 0;                                // Pulse Sensor purple wire connected to analog pin 0
int blinkPin = 11;                       // pin to blink led at each beat
int fadePin = 5;                                 // pin to do fancy classy fading blink at each beat
int fadeRate = 0;                                // used to fade LED on with PWM on fadePin
int ledsinal = 8;

// these variables are volatile because they are used during the interrupt service routine!
volatile int BPM;                                // used to hold the pulse rate
volatile int Signal;                     // holds the incoming raw data
volatile int IBI = 600;                  // holds the time between beats, the Inter-Beat Interval
volatile boolean Pulse = false;  // true when pulse wave is high, false when it's low
volatile boolean QS = false;     // becomes true when Arduoino finds a beat.
void interruptSetup(){ 
// Initializes Timer2 to throw an interrupt every 2mS.
TCCR2A = 0x02;   // DISABLE PWM ON DIGITAL PINS 3 AND 11, AND GO INTO CTC MODE
TCCR2B = 0x06;   // DON'T FORCE COMPARE, 256 PRESCALER
OCR2A = 0X7C;    // SET THE TOP OF THE COUNT TO 124 FOR 500Hz SAMPLE RATE
TIMSK2 = 0x02;   // ENABLE INTERRUPT ON MATCH BETWEEN TIMER2 AND OCR2A
sei();                   // MAKE SURE GLOBAL INTERRUPTS ARE ENABLED    
}

// THIS IS THE TIMER 2 INTERRUPT SERVICE ROUTINE.
// Timer 2 makes sure that we take a reading every 2 miliseconds
ISR(TIMER2_COMPA_vect){                                          // triggered when Timer2 counts to 124
cli();                                                                   // disable interrupts while we do this
Signal = analogRead(pulsePin);                   // read the Pulse Sensor
sampleCounter += 2;                                              // keep track of the time in mS with this variable
int N = sampleCounter - lastBeatTime;    // monitor the time since the last beat to avoid noise
// find the peak and trough of the pulse wave
if(Signal < thresh && N > (IBI/5)*3){    // avoid dichrotic noise by waiting 3/5 of last IBI
         if (Signal < T){                                        // T is the trough
                 T = Signal;                                             // keep track of lowest point in pulse wave
                 }
         }
       
if(Signal > thresh && Signal > P){               // thresh condition helps avoid noise
         P = Signal;                                                     // P is the peak
         }                                                                       // keep track of highest point in pulse wave

// NOW IT'S TIME TO LOOK FOR THE HEART BEAT
// signal surges up in value every time there is a pulse
if (N > 250){                                                            // avoid high frequency noise
if ( (Signal > thresh) && (Pulse == false) && (N > (IBI/5)*3) ){       
Pulse = true;                                                    // set the Pulse flag when we think there is a pulse
digitalWrite(blinkPin,HIGH);                     // turn on pin 13 LED
IBI = sampleCounter - lastBeatTime;              // measure time between beats in mS
lastBeatTime = sampleCounter;                    // keep track of time for next pulse
               
                 if(firstBeat){                                          // if it's the first time we found a beat, if firstBeat == TRUE
                         firstBeat = false;                              // clear firstBeat flag
                         return;                                                 // IBI value is unreliable so discard it
                 }
                 if(secondBeat){                                         // if this is the second beat, if secondBeat == TRUE
                 secondBeat = false;                             // clear secondBeat flag
                         for(int i=0; i<=9; i++){                // seed the running total to get a realisitic BPM at startup
                                 rate[i] = IBI;                                
                                 }
                 }
               
// keep a running total of the last 10 IBI values
word runningTotal = 0;                           // clear the runningTotal variable
for(int i=0; i<=8; i++){                         // shift data in the rate array
                 rate[i] = rate[i+1];                    // and drop the oldest IBI value
                 runningTotal += rate[i];                // add up the 9 oldest IBI values
         }
       
rate[9] = IBI;                                           // add the latest IBI to the rate array
runningTotal += rate[9];                         // add the latest IBI to runningTotal
runningTotal /= 10;                                      // average the last 10 IBI values
BPM = 60000/runningTotal;                        // how many beats can fit into a minute? that's BPM! AQUI
QS = true;                                                       // set Quantified Self flag
// QS FLAG IS NOT CLEARED INSIDE THIS ISR
}                                      
}
if (Signal < thresh && Pulse == true){   // when the values are going down, the beat is over
         digitalWrite(blinkPin,LOW);             // turn off pin 13 LED
         Pulse = false;                                          // reset the Pulse flag so we can do it again
         amp = P - T;                                            // get amplitude of the pulse wave
         thresh = amp/2 + T;                             // set thresh at 50% of the amplitude
         P = thresh;                                             // reset these for next time
         T = thresh;
         }

if (N > 2500){                                                   // if 2.5 seconds go by without a beat
         thresh = 512;                                           // set thresh default
         P = 512;                                                        // set P default
         T = 512;                                                        // set T default
         lastBeatTime = sampleCounter;           // bring the lastBeatTime up to date  
         firstBeat = true;                                       // set these to avoid noise
         secondBeat = true;                                      // when we get the heartbeat back
         }

sei();                                                                   // enable interrupts when youre done!
}// end isr


void setup(){
pinMode(blinkPin,OUTPUT);                // pin that will blink to your heartbeat!
pinMode(fadePin,OUTPUT);                 // pin that will fade to your heartbeat!
pinMode(ledsinal,OUTPUT);
Serial.begin(115200);                    // we agree to talk fast!
interruptSetup();                                // sets up to read Pulse Sensor signal every 2mS
// UN-COMMENT THE NEXT LINE IF YOU ARE POWERING The Pulse Sensor AT LOW VOLTAGE,
// AND APPLY THAT VOLTAGE TO THE A-REF PIN
//analogReference(EXTERNAL);
}

void loop(){

ledFadeToBeat();
led();
delay(20);                                                       // take a break
}

void ledFadeToBeat(){
fadeRate -= 15;                                          // set LED fade value
fadeRate = constrain(fadeRate,0,255); // keep LED fade value from going into negative numbers!
analogWrite(fadePin,fadeRate);           // fade LED
}

int led() {

if (BPM1 > 70) {
digitalWrite(ledsinal, HIGH);}
else{
         digitalWrite(ledsinal, LOW);}}