hack gt final code
Dependencies: 4DGL-uLCD-SE BMP085 PinDetect SDFileSystem mbed wave_player
Diff: Heart.cpp
- Revision:
- 8:0620e2461b3a
- Child:
- 14:23390a020d1c
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/Heart.cpp Sun Sep 21 01:38:00 2014 +0000 @@ -0,0 +1,153 @@ +#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! +} \ No newline at end of file