HRV 0.04: Modify to work with new heart rate API, but still not sure it's working correctly

apps.json

@@ -2735,7 +2735,7 @@
   "name": "Heart Rate Variability monitor",
   "shortName":"HRV monitor",
   "icon": "hrv.png",
-  "version":"0.03",
+  "version":"0.04",
   "description": "Heart Rate Variability monitor, see Readme for more info",
   "tags": "",
   "readme": "README.md",

apps/HRV/ChangeLog

@@ -1,3 +1,4 @@
 0.01: New App!
 0.02: Added options to either run as a one-off reading, or a continuous mode to log data until the watch is reset
 0.03: Add RMSSD recording
+0.04: Modify to work with new heart rate API, but still not sure it's working correctly

apps/HRV/app.js

@@ -17,22 +17,23 @@ var csv = [
 logfile.write(csv.join(",")+"\n");
 
 var debugging = true;
+var samples = 0; // how many samples have we connected?
+var collectData = false; // are we currently collecting data?
 
-var first_signals = 0; // ignore the first several signals
-var heartrate = [];
 var BPM_array = [];
 var raw_HR_array = new Float32Array(1536);
 var alternate_array = new Float32Array(3072);
 var pulse_array = [];
-var pulsecount = 0;
 var cutoff_threshold = 0.5;
 var sample_frequency = 51.6;
 var gap_threshold = 0.15;
-var hr_min = 40;
-var hr_max = 160;
 var movement = 0;
 
-function storeMyData(data, file_type) {
+var px = g.getWidth()/2;
+var py = g.getHeight()/2;
+var accel; // interval for acceleration logging
+
+function storeMyData(data, file_type) { "ram"
     log = raw_HR_array;
     // shift elements backwards - note the 4, because a Float32 is 4 bytes
     log.set(new Float32Array(log.buffer, 4 /*bytes*/));
@@ -41,59 +42,58 @@ function storeMyData(data, file_type) {
 }
 
 function average(samples) {
-    var sum = 0;
+  return E.sum(samples) / samples.length; // faster builtin
+   /* var sum = 0;
     for (var i = 0; i < samples.length; i++) {
         sum += parseFloat(samples[i]);
     }
     var avg = sum / samples.length;
-    return avg;
+    return avg;*/
 }
 
 function StandardDeviation (array) {
   const n = array.length;
-  const mean = array.reduce((a, b) => a + b) / n;
+  const mean = E.sum(array) / n; //array.reduce((a, b) => a + b) / n;
-  return Math.sqrt(array.map(x => Math.pow(x - mean, 2)).reduce((a, b) => a + b) / n);
+  //return Math.sqrt(array.map(x => Math.pow(x - mean, 2)).reduce((a, b) => a + b) / n);
+  return Math.sqrt(E.variance(array, mean));
 }
 
 function turn_off() {
     Bangle.setHRMPower(0);
 
-    var accel = setInterval(function () {
-    movement = movement + Bangle.getAccel().diff;
-    }, 1000);
 
     g.clear();
-    g.drawString("processing 1/5", 120, 120);
+    g.drawString("processing 1/5", px, py);
 
     rolling_average(raw_HR_array,5);
     g.clear();
-    g.drawString("processing 2/5", 120, 120);
+    g.drawString("processing 2/5", px, py);
 
     upscale();
     g.clear();
-    g.drawString("processing 3/5", 120, 120);
+    g.drawString("processing 3/5", px, py);
 
     rolling_average(alternate_array,5);
     g.clear();
-    g.drawString("processing 4/5", 120, 120);
+    g.drawString("processing 4/5", px, py);
 
     apply_cutoff();
     find_peaks();
 
     g.clear();
-    g.drawString("processing 5/5", 120, 120);
+    g.drawString("processing 5/5", px, py);
 
     calculate_HRV();
 }
 
-function bernstein(A, B, C, D, E, t) {
+function bernstein(A, B, C, D, E, t) { "ram"
     s = 1 - t;
     x = (A * Math.pow(s, 4)) + (B * 4 * Math.pow(s, 3) * t) + (C * 6 * s * s * t * t)
         + (D * 4 * s * Math.pow(t, 3)) + (E * Math.pow(t, 4));
     return x;
 }
 
-function upscale() {
+function upscale() { "ram"
     var index = 0;
     for (let i = raw_HR_array.length - 1; i > 5; i -= 5) {
         p0 = raw_HR_array[i];
@@ -110,19 +110,18 @@ function upscale() {
     }
 }
 
-function rolling_average(values, count) {
+function rolling_average(values, count) { "ram"
     var temp_array = [];
 
     for (let i = 0; i < values.length; i++) {
             temp_array = [];
             for (let x = 0; x < count; x++)
                 temp_array.push(values[i + x]);
-           
                 values[i] = average(temp_array);
     }
 }
 
-function apply_cutoff() {
+function apply_cutoff() { "ram"
     var x;
     for (let i = 0; i < alternate_array.length; i++) {
         x = alternate_array[i];
@@ -132,7 +131,7 @@ function apply_cutoff() {
     }
 }
 
-function find_peaks() {
+function find_peaks() { "ram"
     var previous;
     var previous_slope = 0;
     var slope;
@@ -157,7 +156,7 @@ function find_peaks() {
     }
 }
 
-function RMSSD(samples){
+function RMSSD(samples){ "ram"
   var sum = 0;
   var square = 0;
   var data = [];
@@ -192,7 +191,7 @@ function calculate_HRV() {
     gap_average = average(temp_array);
     var calculatedHR = (sample_frequency*60)/(gap_average/2);
     if(option == 0)
-          g.flip();
+          Bangle.setLCDPower(1);
     g.clear();
     //var display_stdv = StandardDeviation(pulse_array).toFixed(1);
     var SDNN = (StandardDeviation(temp_array) * (1 / (sample_frequency * 2) * 1000)).toFixed(0);
@@ -200,14 +199,13 @@ function calculate_HRV() {
     g.drawString("SDNN:" + SDNN
                  +"\nRMSSD:" + RMS_SD
                 + "\nHR:" + calculatedHR.toFixed(0)
-                 +"\nSample Count:" + temp_array.length, 120, 120);
+                 +"\nSample Count:" + temp_array.length, px, py);
-   
+    Bangle.setLCDPower(1);
-    if(option == 0){
+    if(option == 0) { // single run
       Bangle.buzz(500,1);
-      clearInterval(routine);
+      option = null;
-    }
+      drawButtons();
- 
+    } else {
-    else{
       var csv = [
           0|getTime(),
           temp_array.length,
@@ -219,85 +217,87 @@ function calculate_HRV() {
           ];
       logfile.write(csv.join(",")+"\n");
 
-      movement = 0;
+
    //   for (let i = 0; i < raw_HR_array.length; i++) {
      //     raw_HR_array[i] = null;
       //}
+
+      turn_on();
     }
 }
 
 function btn1Pressed() {
   if(option === null){
-    clearInterval(accel);
     g.clear();
-    g.drawString("one-off assessment", 120, 120);
+    g.drawString("one-off assessment", px, py);
     option = 0;
-    Bangle.setHRMPower(1);
+
+    turn_on();
   }
 }
 
 function btn3Pressed() {
   if(option === null){
     logfile.write(""); //reset HRV log
-    clearInterval(accel);
     g.clear();
-    g.drawString("continuous mode", 120, 120);
+    g.drawString("continuous mode", px, py);
     option = 1;
-    Bangle.setHRMPower(1);
+
+    turn_on();
   }
 }
 
-var routine = setInterval(function () {
+function turn_on() {
-  clearInterval(accel);
-  first_signals = 0; // ignore the first several signals
-  pulsecount = 0;
   BPM_array = [];
-  heartrate = [];
   pulse_array = [];
-  Bangle.setHRMPower(1);
+  samples = 0;
-}, 180000);
+  if (accel) clearInterval(accel);
-
+  movement = 0;
-var accel = setInterval(function () {
+  accel = setInterval(function () {
     movement = movement + Bangle.getAccel().diff;
   }, 1000);
+  Bangle.setHRMPower(1);
+  collectData = true;
+}
 
-g.clear();
+function drawButtons() {
   g.setColor("#00ff7f");
   g.setFont("6x8", 2);
   g.setFontAlign(-1,1);
   g.drawString("continuous", 120, 210);
-g.setFontAlign(-1,1);
   g.drawString("one-time", 140, 50);
+  g.setColor("#ffffff");
+  g.setFontAlign(0, 0);
+}
 
+g.clear();
+
+drawButtons();
+
+g.setFont("6x8", 2);
 g.setColor("#ffffff");
 g.setFontAlign(0, 0); // center font
-g.drawString("check app README", 120, 120);
+g.drawString("check app README\nfor more info", px, py);
-g.drawString("for more info", 120, 140);
 
 setWatch(btn1Pressed, BTN1, {repeat:true});
 setWatch(btn3Pressed, BTN3, {repeat:true});
 
-Bangle.on('HRM', function (hrm) {
+
-        if(option == 0)
+
-          g.flip();
+Bangle.on('HRM-raw', function (e) {
-        if (first_signals < 3) {
+  if (!collectData) return;
-            g.clear();
+  storeMyData(e.raw, 0);
-            g.drawString("setting up...\nremain still " + first_signals * 20 + "%", 120, 120);
+  if (!(samples & 7)) {
-            first_signals++;
+    Bangle.setLCDPower(1);
+    g.clearRect(0, py-10, g.getWidth(), py+22);
+    if (samples < 100)
+      g.drawString("setting up...\nremain still " + samples + "%", px, py, true);
+    else
+      g.drawString("logging: " + (samples*100/raw_HR_array.length).toFixed(0) + "%", px, py, true);
   }
-        else {
+  if (samples > raw_HR_array.length) {
-            BPM_array = hrm.raw;
+    collectData = false;
-            if(hrm.bpm > hr_min && hrm.bpm < hr_max)
-                heartrate.push(hrm.bpm);
-            if (pulsecount < 7) {
-                for (let i = 0; i < 256; i++) {
-                    storeMyData(BPM_array[i], 0);
-                }
-            g.clear();
-            g.drawString("logging: " + ((pulsecount/6)*100).toFixed(0) + "%", 120, 120);
-            }
-            if(pulsecount == 6)
     turn_off();
-            pulsecount++;
   }
+  samples++;
 });