#include #include LiquidCrystal lcd(12,11,5,4,3,2); // VARIABLES int pulsePin = 0; // Pulse Sensor purple wire connected to analog pin 0 int blinkPin = 13; // 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 const int lm35_pin = A1; //LM35 O/P pin // 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, must be seeded! 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. 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 setup(){ pinMode(blinkPin,OUTPUT); // pin that will blink to your heartbeat! pinMode(fadePin,OUTPUT); // pin that will fade to your heartbeat! 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); lcd.begin(16,2); lcd.setCursor(0,1); lcd.print("Patient Health"); lcd.setCursor(1,5); lcd.print("Monitoring"); lcd.clear(); } void loop(){ sendDataToProcessing('S', Signal); // send Processing the raw Pulse Sensor data 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 sendDataToProcessing('B',BPM); // send heart rate with a 'B' prefix sendDataToProcessing('Q',IBI); // send time between beats with a 'Q' prefix QS = false; // reset the Quantified Self flag for next time } ledFadeToBeat(); TempOutput(); HeartOutput(); delay(20); // take a break } void TempOutput() { int temp_adc_val; float temp_val; temp_adc_val = analogRead(lm35_pin); /* Read Temperature */ temp_val = (temp_adc_val * 4.88); /* Convert adc value to equivalent voltage */ temp_val = (temp_val/10); /* LM35 gives output of 10mv/°C */ lcd.setCursor(1,0); lcd.print("Temprature: "); lcd.setCursor(0,13); lcd.print(temp_val); delay(1000); lcd.clear(); } void HeartOutput() { lcd.setCursor(0,1); lcd.print("BPM: "); lcd.setCursor(0,6); lcd.print(BPM); delay(300); lcd.clear(); } 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 } 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 } 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 } // 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