sleeprec.app.js

// record heart beat while sleeping

var MEASURE_PERIOD = 15*60*1000; // 15 min
var SAMPLE_TIME = 3*60*1000; // 3 min
var DISPOSE_TIME = 30*1000; // 30 sec

var sumBPM;
var sumCount;
var csvFile;

function init() {
  d = new Date();
  loc = require('locale');
  locTime = `${loc.date(d)}_${loc.time(d)}`.trim().split(/[\/:]/).join('');

  csvName = `sleeprec.bpm.${locTime}.csv`;
  csvFile = require("Storage").open(csvName, 'w');
  csvFile.write(`time, bpm, ${locTime}\n`);

  Bangle.on('HRM', function(hrm) {
    console.log(`hrm ${hrm.bpm} , ${hrm.confidence}`);
    if (hrm.confidence < 100)
      return;
    sumBPM += hrm.bpm;
    sumCount++;
  });

  E.showMessage('Waiting...', 'sleeprec');
}

function record() {
  avg = Math.floor(sumBPM/sumCount + 0.5);
//  console.log(`sum ${sumBPM}, cnt ${sumCount}, avg ${avg}`);
  t = require('locale').time(new Date()).trim();
  csvFile.write(`${t}, ${avg}\n`);
}

init();
setInterval(() => {
  Bangle.setHRMPower(1);
  setTimeout(()=> { // dispose first N sec bpm
    E.showMessage('Recoding...', 'sleeprec');
    sumBPM = 0;
    sumCount = 0;
    setTimeout(()=>{
      record();
      Bangle.setHRMPower(0);
      E.showMessage('Waiting...', 'sleeprec');
    }, SAMPLE_TIME);
  }, DISPOSE_TIME);
}, MEASURE_PERIOD);