Link to Pulse Sensor Code:

http://pulsesensor.myshopify.com/pages/code-and-guide

Link to LED Code:

https://learn.adafruit.com/adafruit-neopixel-uberguide/arduino-library

volatile int rate[10]; // array to hold last ten IBI values

volatile unsigned long sampleCounter = 0; // used to determine pulse timing

volatile unsigned long lastBeatTime = 0; // used to find IBI

volatile int P =512; // used to find peak in pulse wave, seeded

volatile int T = 512; // used to find trough in pulse wave, seeded

volatile int thresh = 512; // used to find instant moment of heart beat, seeded

volatile int amp = 100; // used to hold amplitude of pulse waveform, seeded

volatile boolean firstBeat = true; // used to seed rate array so we startup with reasonable BPM

volatile boolean secondBeat = false; // used to seed rate array so we startup with reasonable BPM

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(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;

}

}

if(firstBeat){ // if it's the first time we found a beat, if firstBeat == TRUE

firstBeat = false; // clear firstBeat flag

secondBeat = true; // set the second beat flag

sei(); // enable interrupts again

return; // IBI value is unreliable so discard it

}

// 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!

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 = false; // when we get the heartbeat back

}

sei(); // enable interrupts when youre done!

}// end isr

#include <Adafruit_NeoPixel.h>

#define PIN 6

//This code is for Pulse Sensor Amped by Joel Murphy and Yury Gitman

int pulsePin = 0;

int blinkPin = 13;

int fadeRate = 0;

int blinkRate = 0;

int time = 0;

int startMilliCount = 0;

int blinkCounter = 0;

int volVal = 0;

int volMax = 0;

int volFadeRate = 0;

volatile int BPM;

volatile int Signal;

volatile int IBI = 600;

volatile boolean Pulse = false;

volatile boolean QS = false;

Adafruit_NeoPixel strip = Adafruit_NeoPixel(30, PIN, NEO_GRB + NEO_KHZ800);

void setup(){

strip.begin();

strip.show();

Serial.begin(115200);

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(){

//sendDataToProcessing('S', Signal); // send Processing the raw Pulse Sensor data

int sensorValue = analogRead(A1);

if (QS == true){ // Quantified Self flag is true when arduino finds a heartbeat

//fadeRate = 255; // Set 'fadeRate' Variable to 255 to fade LED with pulse

//Serial.println(BPM);

//sendDataToProcessing('B',BPM); // send heart rate with a 'B' prefix

//sendDataToProcessing('Q',IBI); // send time between beats with a 'Q' prefix

//startMilliCount = millis();

Serial.println(IBI);

QS = false; // reset the Quantified Self flag for next time

}

sensorValue = constrain(sensorValue, 555, 905);

volVal = sensorValue;

if(volVal > volMax - 15){

volMax = volVal;

volFadeRate = 255;

}

aggregateShow(BPM);

int lightVal = map(sensorValue, 555, 905, 0, 255);

beatLight(lightVal);

time = millis()-startMilliCount;

if(time >= IBI)

{

startMilliCount = millis();

time = 0;

fadeRate = 175;

Serial.print("blink ");

Serial.println(blinkCounter);

blinkCounter++;

}

ledFadeToBeat();

if(time > 5000)

{

time = 0;

blinkCounter++;

}

delay(20); // take a break

}

void ledFadeToBeat(){

fadeRate -= 15; // set LED fade value

fadeRate = constrain(fadeRate,0,175); // keep LED fade value from going into negative numbers!

setBrightness(strip.Color(fadeRate, fadeRate, fadeRate)); // fade LED

}

void setBrightness(uint32_t c){

for(int i =0; i<10; i++)

{

strip.setPixelColor(i,c);

strip.show();

}

}

void beatLight(int brightness){

for(int i =20; i<30; i++)

{

strip.setPixelColor(i, strip.Color(brightness, brightness, brightness));

strip.show();

}

}

void aggregateShow(int heartRate){

for(int i = 10; i < 20; i++)

{

strip.setPixelColor(i, Wheel(volFadeRate));

}

strip.show();

volFadeRate -= int(heartRate/3);

}

void sendDataToProcessing(char symbol, int data ){

//Serial.print(symbol); // symbol prefix tells Processing what type of data is coming

//Serial.println(data); // the data to send culminating in a carriage return

}

uint32_t Wheel(byte WheelPos){

if(WheelPos < 85) {

return strip.Color(WheelPos * 3, 255 - WheelPos * 3, 0);

} else if(WheelPos < 170) {

WheelPos -= 85;

return strip.Color(255 - WheelPos * 3, 0, WheelPos * 3);

} else {

WheelPos -= 170;

return strip.Color(0, WheelPos * 3, 255 - WheelPos * 3);

}

}