hack gt final code
Dependencies: 4DGL-uLCD-SE BMP085 PinDetect SDFileSystem mbed wave_player
Heart.cpp
- Committer:
- otis22894
- Date:
- 2014-09-21
- Revision:
- 8:0620e2461b3a
- Child:
- 14:23390a020d1c
File content as of revision 8:0620e2461b3a:
#include "Heart.h" #include "mbed.h" 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 bool firstBeat = true; // used to seed rate array so we startup with reasonable BPM volatile bool secondBeat = false; // used to seed rate array so we startup with reasonable BPM 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 bool Pulse = false; // true when pulse wave is high, false when it's low volatile bool QS = false; // becomes true when Arduoino finds a beat. volatile bool isBeating = false; volatile int beatCount = 0; volatile int PulseLength = 0; AnalogIn ain(p17); DigitalOut myLED(LED1); Ticker pulseReader; Heart :: Heart() { } void Heart :: startReading() { pulseReader.attach(this, &Heart::sample, .002f); } void Heart :: stopReading() { pulseReader.detach(); __enable_irq(); } void Heart :: reset() { sampleCounter = 0; // used to determine pulse timing lastBeatTime = 0; // used to find IBI P =512; // used to find peak in pulse wave, seeded T = 512; // used to find trough in pulse wave, seeded thresh = 512; // used to find instant moment of heart beat, seeded amp = 100; // used to hold amplitude of pulse waveform, seeded firstBeat = true; // used to seed rate array so we startup with reasonable BPM secondBeat = false; // used to seed rate array so we startup with reasonable BPM IBI = 600; // holds the time between beats, must be seeded! Pulse = false; // true when pulse wave is high, false when it's low QS = false; // becomes true when Arduoino finds a beat. isBeating = false; beatCount = 0; PulseLength = 0; } bool Heart :: beatDetected() { return isBeating; } int Heart :: beatsCounted() { return beatCount; } // THIS IS THE TIMER 2 INTERRUPT SERVICE ROUTINE. // Timer 2 makes sure that we take a reading every 2 miliseconds void Heart :: sample() { // triggered when Timer2 counts to 124 __disable_irq(); float readVal = ain; // disable interrupts while we do this Signal = ain * 1024; // 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 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 __enable_irq(); // enable interrupts again return; // IBI value is unreliable so discard it } // keep a running total of the last 10 IBI values unsigned short 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 myLED = 1; } } if(Pulse) { PulseLength+=2; if (Signal < thresh){ // when the values are going down, the beat is over myLED = 0; // 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 //if (PulseLength > 4 && amp > (T/2)) { if (PulseLength > 4 && amp > (T/3)) { isBeating = true; beatCount++; } thresh = amp/2 + T; // set thresh at 50% of the amplitude P = thresh; // reset these for next time T = thresh; PulseLength = 0; } } 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 isBeating = false; } __enable_irq(); // enable interrupts when youre done! }