zohra moutaouakkil
/
HeartPulseModify
heart rate mesuarement
main.cpp
- Committer:
- zmoutaou
- Date:
- 2020-01-27
- Revision:
- 3:89dc4a1464e3
- Parent:
- 2:515e6791dfe2
File content as of revision 3:89dc4a1464e3:
#include "mbed.h" #include "USBSerial.h" #include "Adafruit_SSD1306.h" #include <string> #include <sstream> #include <map> AnalogIn pulseIn(A0); using namespace std; USBSerial pc; I2C i2c(PB_9, PB_8); Adafruit_SSD1306_I2c oled(i2c,PC_13); AnalogIn pulsePin(A0); //This is signal input // these variables are because they are used during the interrupt service routine! int BPM; // used to hold the pulse rate int Signal; // holds the incoming raw data int IBI = 600; // holds the time between beats, the Inter-Beat Interval bool Pulse = false; // true when pulse wave is high, false when it's low bool QS = false; // becomes true when Arduoino finds a beat. void heart_rate_test(void); int rate[10]; // used to hold last ten IBI values unsigned long sampleCounter = 0; // used to determine pulse timing unsigned long lastBeatTime = 0; // used to find the inter beat interval int P =512; // used to find peak in pulse wave int T = 512; // used to find trough in pulse wave int thresh = 512; // used to find instant moment of heart beat int amp = 100; // used to hold amplitude of pulse waveform bool firstBeat = true; // used to seed rate array so we startup with reasonable BPM bool secondBeat = true; // used to seed rate array so we startup with reasonable BPM Ticker time_up; // Escreve o texto passado como parâmetro no display void OLED_writeString(string str, int x, int y) { oled.clearDisplay(); oled.setTextCursor(x, y); oled.fillRect(x, y, 128, 8, 0); } void heart_rate_test() { Signal = pulsePin.read()*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 nois // 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 long 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; string BPM_s= static_cast<ostringstream*>( &(ostringstream() << BPM) )->str(); OLED_writeString(BPM_s, 1, 1); // QS FLAG IS NOT CLEARED INSIDE THIS ISR } } if (Signal < thresh && Pulse == true) { // when the values are going down, the beat is over 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 } } int main() { time_up.attach(&heart_rate_test, 0.002); oled.clearDisplay(); OLED_writeString("hello world", 1, 1); while(true) { if (QS == true) { QS = false; pc.printf("%d \n ",BPM); // reset the Quantified Self flag for next time } wait_ms(20); } }