forked from FOSS/BangleApps
83 lines
2.0 KiB
JavaScript
83 lines
2.0 KiB
JavaScript
// a variation on the hrm app
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Bangle.setLCDPower(1);
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Bangle.setLCDTimeout(0);
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Bangle.ioWr(0x80,0)
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x=0;
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var min=0,max=0;
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var wasHigh = 0, wasLow = 0;
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var lastHigh = getTime();
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var hrmList = [];
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var hrm;
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var SPEAKER_PIN = D18;
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function freq(f) {
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console.log("frequency: ", f);
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if (f===0) digitalWrite(SPEAKER_PIN, 0);
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else analogWrite(SPEAKER_PIN, 0.5, {freq: f});
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}
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function readHRM() {
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var a = analogRead(D29);
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var h = getTime();
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min=Math.min(min*0.97+a*0.03,a);
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max=Math.max(max*0.97+a*0.03,a);
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y = E.clip(170 - (a*960*4),100,230);
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if (x==0) {
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g.clearRect(0,100,239,239);
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g.moveTo(-100,0);
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}
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let frequency = parseFloat((170 - (a*960*4)) + 500);
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if(frequency > 0) freq(frequency);
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g.setColor(1,1,1);
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g.lineTo(x,y);
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if ((max-min)>0.005) {
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if (4*a > (min+3*max)) { // high
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g.setColor(1,0,0);
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g.fillRect(x,230,x,239);
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g.setColor(1,1,1);
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if (!wasHigh && wasLow) {
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var currentHrm = 60/(h-lastHigh);
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lastHigh = h;
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if (currentHrm<250) {
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while (hrmList.length>12) hrmList.shift();
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hrmList.push(currentHrm);
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// median filter
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var t = hrmList.slice(); // copy
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t.sort();
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// average the middle 3
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var mid = t.length>>1;
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if (mid+2<t.length)
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hrm = (t[mid]+t[mid+1]+t[mid+2])/3;
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else if (mid<t.length)
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hrm = t[mid];
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else
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hrm = 0;
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g.setFontVector(40);
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g.setFontAlign(0,0);
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g.clearRect(0,0,239,100);
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var str = hrm ? Math.round(hrm) : "?";
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var px = 120;
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g.drawString(str,px,40);
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px += g.stringWidth(str)/2;
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g.setFont("6x8");
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g.drawString("BPM",px+20,60);
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}
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}
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wasLow = 0;
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wasHigh = 1;
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} else if (4*a < (max+3*min)) { // low
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wasLow = 1;
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} else { // middle
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g.setColor(0.5,0,0);
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g.fillRect(x,230,x,239);
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g.setColor(1,1,1);
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wasHigh = 0;
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}
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}
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x++;
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if (x>239)x=0;
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}
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setInterval(readHRM,50);
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