Takehiko Shimojima / Mbed 2 deprecated AmbientHeartRateMonitor

IoT用クラウドサービス「Ambient」と心拍センサーを使った心拍モニターです。心拍センサー「Pulse Sensor Amped」の値をmbed「Simple IoT Board」で読み、「Ambient」に送信してモニターします。 https://ambidata.io

Dependencies:   AmbientLib SimpleIoTBoardLib mbed

pulseSensor.cpp@0:16d0c9ce5afb, 2016-06-04 (annotated)

Committer:
AmbientData
Date:
Sat Jun 04 02:35:48 2016 +0000
Revision:
0:16d0c9ce5afb
Child:
1:0053efdb355e
Initial submission

Who changed what in which revision?

UserRevisionLine numberNew contents of line
AmbientData 0:16d0c9ce5afb 1 #include "mbed.h"
AmbientData 0:16d0c9ce5afb 2
AmbientData 0:16d0c9ce5afb 3 AnalogIn pulsePin(dp13);
AmbientData 0:16d0c9ce5afb 4 DigitalOut led(dp6);
AmbientData 0:16d0c9ce5afb 5
AmbientData 0:16d0c9ce5afb 6 #define SAMPLING 2000.0f // Sampling period in micro seconds 2msec
AmbientData 0:16d0c9ce5afb 7
AmbientData 0:16d0c9ce5afb 8 volatile int rate[10]; // array to hold last ten IBI values
AmbientData 0:16d0c9ce5afb 9 volatile unsigned long sampleCounter = 0; // used to determine pulse timing
AmbientData 0:16d0c9ce5afb 10 volatile unsigned long lastBeatTime = 0; // used to find IBI
AmbientData 0:16d0c9ce5afb 11 volatile int P =512; // used to find peak in pulse wave, seeded
AmbientData 0:16d0c9ce5afb 12 volatile int T = 512; // used to find trough in pulse wave, seeded
AmbientData 0:16d0c9ce5afb 13 volatile int thresh = 525; // used to find instant moment of heart beat, seeded
AmbientData 0:16d0c9ce5afb 14 volatile int amp = 100; // used to hold amplitude of pulse waveform, seeded
AmbientData 0:16d0c9ce5afb 15 volatile bool firstBeat = true; // used to seed rate array so we startup with reasonable BPM
AmbientData 0:16d0c9ce5afb 16 volatile bool secondBeat = false; // used to seed rate array so we startup with reasonable BPM
AmbientData 0:16d0c9ce5afb 17
AmbientData 0:16d0c9ce5afb 18 // Volatile Variables, used in the interrupt service routine!
AmbientData 0:16d0c9ce5afb 19 volatile int BPM; // int that holds raw Analog in 0. updated every 2mS
AmbientData 0:16d0c9ce5afb 20 volatile int Signal; // holds the incoming raw data
AmbientData 0:16d0c9ce5afb 21 volatile int IBI = 600; // int that holds the time interval between beats! Must be seeded!
AmbientData 0:16d0c9ce5afb 22 volatile bool Pulse = false; // "True" when User's live heartbeat is detected. "False" when not a "live beat".
AmbientData 0:16d0c9ce5afb 23 volatile bool QS = false; // becomes true when Arduoino finds a beat.
AmbientData 0:16d0c9ce5afb 24
AmbientData 0:16d0c9ce5afb 25 Ticker t2;
AmbientData 0:16d0c9ce5afb 26
AmbientData 0:16d0c9ce5afb 27 // THIS IS THE TICKER INTERRUPT SERVICE ROUTINE.
AmbientData 0:16d0c9ce5afb 28 // Ticker makes sure that we take a reading every 2 miliseconds
AmbientData 0:16d0c9ce5afb 29 void sampling() { // triggered every 2 miliseconds
AmbientData 0:16d0c9ce5afb 30 Signal = (int)(pulsePin.read()*1023); // read the Pulse Sensor
AmbientData 0:16d0c9ce5afb 31 sampleCounter += 2; // keep track of the time in mS with this variable
AmbientData 0:16d0c9ce5afb 32 int N = sampleCounter - lastBeatTime; // monitor the time since the last beat to avoid noise
AmbientData 0:16d0c9ce5afb 33
AmbientData 0:16d0c9ce5afb 34 // find the peak and trough of the pulse wave
AmbientData 0:16d0c9ce5afb 35 if(Signal < thresh && N > (IBI/5)*3){ // avoid dichrotic noise by waiting 3/5 of last IBI
AmbientData 0:16d0c9ce5afb 36 if (Signal < T){ // T is the trough
AmbientData 0:16d0c9ce5afb 37 T = Signal; // keep track of lowest point in pulse wave
AmbientData 0:16d0c9ce5afb 38 }
AmbientData 0:16d0c9ce5afb 39 }
AmbientData 0:16d0c9ce5afb 40
AmbientData 0:16d0c9ce5afb 41 if(Signal > thresh && Signal > P){ // thresh condition helps avoid noise
AmbientData 0:16d0c9ce5afb 42 P = Signal; // P is the peak
AmbientData 0:16d0c9ce5afb 43 } // keep track of highest point in pulse wave
AmbientData 0:16d0c9ce5afb 44
AmbientData 0:16d0c9ce5afb 45 // NOW IT'S TIME TO LOOK FOR THE HEART BEAT
AmbientData 0:16d0c9ce5afb 46 // signal surges up in value every time there is a pulse
AmbientData 0:16d0c9ce5afb 47 if (N > 250){ // avoid high frequency noise
AmbientData 0:16d0c9ce5afb 48 if ( (Signal > thresh) && (Pulse == false) && (N > (IBI/5)*3) ){
AmbientData 0:16d0c9ce5afb 49 Pulse = true; // set the Pulse flag when we think there is a pulse
AmbientData 0:16d0c9ce5afb 50 IBI = sampleCounter - lastBeatTime; // measure time between beats in mS
AmbientData 0:16d0c9ce5afb 51 lastBeatTime = sampleCounter; // keep track of time for next pulse
AmbientData 0:16d0c9ce5afb 52
AmbientData 0:16d0c9ce5afb 53 if(secondBeat){ // if this is the second beat, if secondBeat == TRUE
AmbientData 0:16d0c9ce5afb 54 secondBeat = false; // clear secondBeat flag
AmbientData 0:16d0c9ce5afb 55 for(int i=0; i<=9; i++){ // seed the running total to get a realisitic BPM at startup
AmbientData 0:16d0c9ce5afb 56 rate[i] = IBI;
AmbientData 0:16d0c9ce5afb 57 }
AmbientData 0:16d0c9ce5afb 58 }
AmbientData 0:16d0c9ce5afb 59
AmbientData 0:16d0c9ce5afb 60 if(firstBeat){ // if it's the first time we found a beat, if firstBeat == TRUE
AmbientData 0:16d0c9ce5afb 61 firstBeat = false; // clear firstBeat flag
AmbientData 0:16d0c9ce5afb 62 secondBeat = true; // set the second beat flag
AmbientData 0:16d0c9ce5afb 63 return; // IBI value is unreliable so discard it
AmbientData 0:16d0c9ce5afb 64 }
AmbientData 0:16d0c9ce5afb 65
AmbientData 0:16d0c9ce5afb 66 // keep a running total of the last 10 IBI values
AmbientData 0:16d0c9ce5afb 67 unsigned runningTotal = 0; // clear the runningTotal variable
AmbientData 0:16d0c9ce5afb 68
AmbientData 0:16d0c9ce5afb 69 for(int i=0; i<=8; i++){ // shift data in the rate array
AmbientData 0:16d0c9ce5afb 70 rate[i] = rate[i+1]; // and drop the oldest IBI value
AmbientData 0:16d0c9ce5afb 71 runningTotal += rate[i]; // add up the 9 oldest IBI values
AmbientData 0:16d0c9ce5afb 72 }
AmbientData 0:16d0c9ce5afb 73
AmbientData 0:16d0c9ce5afb 74 rate[9] = IBI; // add the latest IBI to the rate array
AmbientData 0:16d0c9ce5afb 75 runningTotal += rate[9]; // add the latest IBI to runningTotal
AmbientData 0:16d0c9ce5afb 76 runningTotal /= 10; // average the last 10 IBI values
AmbientData 0:16d0c9ce5afb 77 BPM = 60000/runningTotal; // how many beats can fit into a minute? that's BPM!
AmbientData 0:16d0c9ce5afb 78 QS = true; // set Quantified Self flag
AmbientData 0:16d0c9ce5afb 79 // QS FLAG IS NOT CLEARED INSIDE THIS ISR
AmbientData 0:16d0c9ce5afb 80 led = 1;
AmbientData 0:16d0c9ce5afb 81 }
AmbientData 0:16d0c9ce5afb 82 }
AmbientData 0:16d0c9ce5afb 83
AmbientData 0:16d0c9ce5afb 84 if (Signal < thresh && Pulse == true){ // when the values are going down, the beat is over
AmbientData 0:16d0c9ce5afb 85 Pulse = false; // reset the Pulse flag so we can do it again
AmbientData 0:16d0c9ce5afb 86 amp = P - T; // get amplitude of the pulse wave
AmbientData 0:16d0c9ce5afb 87 thresh = amp/2 + T; // set thresh at 50% of the amplitude
AmbientData 0:16d0c9ce5afb 88 P = thresh; // reset these for next time
AmbientData 0:16d0c9ce5afb 89 T = thresh;
AmbientData 0:16d0c9ce5afb 90 led = 0;
AmbientData 0:16d0c9ce5afb 91 }
AmbientData 0:16d0c9ce5afb 92
AmbientData 0:16d0c9ce5afb 93 if (N > 2500){ // if 2.5 seconds go by without a beat
AmbientData 0:16d0c9ce5afb 94 thresh = 512; // set thresh default
AmbientData 0:16d0c9ce5afb 95 P = 512; // set P default
AmbientData 0:16d0c9ce5afb 96 T = 512; // set T default
AmbientData 0:16d0c9ce5afb 97 lastBeatTime = sampleCounter; // bring the lastBeatTime up to date
AmbientData 0:16d0c9ce5afb 98 firstBeat = true; // set these to avoid noise
AmbientData 0:16d0c9ce5afb 99 secondBeat = false; // when we get the heartbeat back
AmbientData 0:16d0c9ce5afb 100 }
AmbientData 0:16d0c9ce5afb 101
AmbientData 0:16d0c9ce5afb 102 }
AmbientData 0:16d0c9ce5afb 103
AmbientData 0:16d0c9ce5afb 104 void interruptSetup(){
AmbientData 0:16d0c9ce5afb 105 // Initializes Ticker to throw an interrupt every 2mS.
AmbientData 0:16d0c9ce5afb 106 t2.attach_us(&sampling, SAMPLING);
AmbientData 0:16d0c9ce5afb 107 }
AmbientData 0:16d0c9ce5afb 108
AmbientData 0:16d0c9ce5afb 109