zohra moutaouakkil
/
HeartPulseModify
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main.cpp
00001 #include "mbed.h" 00002 #include "USBSerial.h" 00003 #include "Adafruit_SSD1306.h" 00004 #include <string> 00005 #include <sstream> 00006 #include <map> 00007 00008 AnalogIn pulseIn(A0); 00009 using namespace std; 00010 USBSerial pc; 00011 I2C i2c(PB_9, PB_8); 00012 Adafruit_SSD1306_I2c oled(i2c,PC_13); 00013 00014 00015 AnalogIn pulsePin(A0); //This is signal input 00016 00017 // these variables are because they are used during the interrupt service routine! 00018 int BPM; // used to hold the pulse rate 00019 int Signal; // holds the incoming raw data 00020 int IBI = 600; // holds the time between beats, the Inter-Beat Interval 00021 bool Pulse = false; // true when pulse wave is high, false when it's low 00022 bool QS = false; // becomes true when Arduoino finds a beat. 00023 00024 void heart_rate_test(void); 00025 int rate[10]; // used to hold last ten IBI values 00026 unsigned long sampleCounter = 0; // used to determine pulse timing 00027 unsigned long lastBeatTime = 0; // used to find the inter beat interval 00028 int P =512; // used to find peak in pulse wave 00029 int T = 512; // used to find trough in pulse wave 00030 int thresh = 512; // used to find instant moment of heart beat 00031 int amp = 100; // used to hold amplitude of pulse waveform 00032 bool firstBeat = true; // used to seed rate array so we startup with reasonable BPM 00033 bool secondBeat = true; // used to seed rate array so we startup with reasonable BPM 00034 00035 Ticker time_up; 00036 // Escreve o texto passado como parâmetro no display 00037 void OLED_writeString(string str, int x, int y) { 00038 oled.clearDisplay(); 00039 oled.setTextCursor(x, y); 00040 oled.fillRect(x, y, 128, 8, 0); 00041 } 00042 00043 00044 void heart_rate_test() 00045 { 00046 Signal = pulsePin.read()*1024; // read the Pulse Sensor 00047 sampleCounter += 2; // keep track of the time in mS with this variable 00048 int N = sampleCounter - lastBeatTime; // monitor the time since the last beat to avoid nois // find the peak and trough of the pulse wave 00049 if(Signal < thresh && N > (IBI/5)*3) { // avoid dichrotic noise by waiting 3/5 of last IBI 00050 if (Signal < T) { // T is the trough 00051 T = Signal; // keep track of lowest point in pulse wave 00052 } 00053 } 00054 00055 if(Signal > thresh && Signal > P) { // thresh condition helps avoid noise 00056 P = Signal; // P is the peak 00057 } // keep track of highest point in pulse wave 00058 00059 // NOW IT'S TIME TO LOOK FOR THE HEART BEAT 00060 // signal surges up in value every time there is a pulse 00061 if (N > 250) { // avoid high frequency noise 00062 if ( (Signal > thresh) && (Pulse == false) && (N > (IBI/5)*3) ) { 00063 Pulse = true; // set the Pulse flag when we think there is a pulse 00064 //digitalWrite(blinkPin,HIGH); // turn on pin 13 LED 00065 IBI = sampleCounter - lastBeatTime; // measure time between beats in mS 00066 lastBeatTime = sampleCounter; // keep track of time for next pulse 00067 00068 if(firstBeat) { // if it's the first time we found a beat, if firstBeat == TRUE 00069 firstBeat = false; // clear firstBeat flag 00070 return; // IBI value is unreliable so discard it 00071 } 00072 if(secondBeat) { // if this is the second beat, if secondBeat == TRUE 00073 secondBeat = false; // clear secondBeat flag 00074 for(int i=0; i<=9; i++) { // seed the running total to get a realisitic BPM at startup 00075 rate[i] = IBI; 00076 } 00077 } 00078 00079 // keep a running total of the last 10 IBI values 00080 long runningTotal = 0; // clear the runningTotal variable 00081 00082 for(int i=0; i<=8; i++) { // shift data in the rate array 00083 rate[i] = rate[i+1]; // and drop the oldest IBI value 00084 runningTotal += rate[i]; // add up the 9 oldest IBI values 00085 } 00086 00087 rate[9] = IBI; // add the latest IBI to the rate array 00088 runningTotal += rate[9]; // add the latest IBI to runningTotal 00089 runningTotal /= 10; // average the last 10 IBI values 00090 BPM = 60000/runningTotal; // how many beats can fit into a minute? that's BPM! 00091 QS = true; 00092 string BPM_s= static_cast<ostringstream*>( &(ostringstream() << BPM) )->str(); 00093 OLED_writeString(BPM_s, 1, 1); 00094 // QS FLAG IS NOT CLEARED INSIDE THIS ISR 00095 } 00096 } 00097 00098 if (Signal < thresh && Pulse == true) { // when the values are going down, the beat is over 00099 Pulse = false; // reset the Pulse flag so we can do it again 00100 amp = P - T; // get amplitude of the pulse wave 00101 thresh = amp/2 + T; // set thresh at 50% of the amplitude 00102 P = thresh; // reset these for next time 00103 T = thresh; 00104 } 00105 00106 if (N > 2500) { // if 2.5 seconds go by without a beat 00107 thresh = 512; // set thresh default 00108 P = 512; // set P default 00109 T = 512; // set T default 00110 lastBeatTime = sampleCounter; // bring the lastBeatTime up to date 00111 firstBeat = true; // set these to avoid noise 00112 secondBeat = true; // when we get the heartbeat back 00113 } 00114 00115 00116 } 00117 00118 00119 int main() 00120 { 00121 time_up.attach(&heart_rate_test, 0.002); 00122 oled.clearDisplay(); 00123 OLED_writeString("hello world", 1, 1); 00124 while(true) 00125 { 00126 if (QS == true) 00127 { 00128 00129 QS = false; 00130 pc.printf("%d \n ",BPM); // reset the Quantified Self flag for next time 00131 } 00132 wait_ms(20); 00133 } 00134 } 00135 00136 00137 00138
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