diff --git a/apps/HRV/HRV.js b/apps/HRV/HRV.js new file mode 100644 index 000000000..98f577293 --- /dev/null +++ b/apps/HRV/HRV.js @@ -0,0 +1,205 @@ +var file = require("Storage").open("HR_log.csv", "w"); +file.write(""); //reset log + +file = require("Storage").open("HR_log.csv", "a"); + +//debugging or analysis files +var cutoff_file = require("Storage").open("cuttoff.csv", "w"); +var peaks_file = require("Storage").open("peaks.csv", "w"); +var debugging = true; + +var first_signals = 0; // ignore the first several signals +var heartrate = []; +var BPM_array = []; +var raw_HR_array = new Float32Array(1024); +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; + +g.setFontAlign(0, 0); // center font +g.setFont("6x8", 2); + +function storeMyData(data, file_type) { + log = raw_HR_array; + // shift elements backwards - note the 4, because a Float32 is 4 bytes + log.set(new Float32Array(log.buffer, 4 /*bytes*/)); + // add ad final element + log[log.length - 1] = data; +} + +function average(samples) { + var sum = 0; + for (var i = 0; i < samples.length; i++) { + sum += parseFloat(samples[i]); + } + var avg = sum / samples.length; + return avg; +} + +function StandardDeviation(data) { + var m = average(data); + return Math.sqrt(data.reduce(function (sq, n) { + return sq + Math.pow(n - m, 2); + }, 0) / (data.length - 1)); +} + +function turn_off() { + Bangle.setHRMPower(0); + + g.clear(); + g.drawString("processing 1/5", 120, 120); + + rolling_average(raw_HR_array,5); + g.clear(); + g.drawString("processing 2/5", 120, 120); + + upscale(); + g.clear(); + g.drawString("processing 3/5", 120, 120); + + rolling_average(alternate_array,5); + g.clear(); + g.drawString("processing 4/5", 120, 120); + + apply_cutoff(); + if(debugging) + for (let i = 0; i < 256; i++) { + cutoff_file.write(alternate_array[i] + "," + "\n"); + } + + find_peaks(); + if(debugging) + for (let i = 0; i < pulse_array.length; i++) { + peaks_file.write(pulse_array[i] + "," + "\n"); + } + g.clear(); + g.drawString("processing 5/5", 120, 120); + + calculate_HRV(); +} + +function bernstein(A, B, C, D, E, t) { + 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() { + var index = 0; + for (let i = raw_HR_array.length - 1; i > 5; i -= 5) { + p0 = raw_HR_array[i]; + p1 = raw_HR_array[i - 1]; + p2 = raw_HR_array[i - 2]; + p3 = raw_HR_array[i - 3]; + p4 = raw_HR_array[i - 4]; + for (let T = 0; T < 100; T += 10) { + x = T / 100; + D = bernstein(p0, p1, p2, p3, p4, x); + alternate_array[index] = D; + index++; + } + } +} + +function rolling_average(values, count) { + 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() { + var x; + for (let i = 0; i < alternate_array.length; i++) { + x = alternate_array[i]; + if (x < cutoff_threshold) + x = cutoff_threshold; + alternate_array[i] = x; + } +} + +function find_peaks() { + var previous; + var previous_slope = 0; + var slope; + var gap_size = 0; + var temp_array = []; + + for (let i = 0; i < alternate_array.length; i++) { + if (previous == null) + previous = alternate_array[i]; + slope = alternate_array[i] - previous; + if (slope * previous_slope < 0) { + if (gap_size > 30) { + pulse_array.push(gap_size); + gap_size = 0; + } + } + else { + gap_size++; + } + previous_slope = slope; + previous = alternate_array[i]; + } +} + +function calculate_HRV() { + var gap_average = average(pulse_array); + var temp_array = []; + var gap_max = (1 + gap_threshold) * gap_average; + var gap_min = (1 - gap_threshold) * gap_average; + for (let i = 0; i < pulse_array.length; i++) { + if (pulse_array[i] > gap_min && pulse_array[i] < gap_max) + temp_array.push(pulse_array[i]); + } + gap_average = average(temp_array); + var calculatedHR = (sample_frequency*60)/(gap_average/2); + g.flip(); + g.clear(); + //var display_stdv = StandardDeviation(pulse_array).toFixed(1); + var HRV = (StandardDeviation(temp_array) * (1 / (sample_frequency * 2) * 1000)).toFixed(0); + g.drawString("HRV:" + HRV + "\nHR:" + calculatedHR.toFixed(0) + +"\nSample Count:" + temp_array.length, 120, 120); + Bangle.buzz(500,1); +} + +g.clear(); +g.drawString("preparing", 120, 120); + +Bangle.setHRMPower(1); + +Bangle.on('HRM', function (hrm) { + g.flip(); + if (first_signals < 5) { + g.clear(); + g.drawString("setting up...\nremain still " + first_signals * 20 + "%", 120, 120); + first_signals++; + } + else { + BPM_array = hrm.raw; + if(hrm.bpm > hr_min && hrm.bpm < hr_max) + heartrate.push(hrm.bpm); + if (pulsecount < 7) { + for (let i = 0; i < 256; i++) { + file.write(BPM_array[i]+","+"\n"); + storeMyData(BPM_array[i], 0); + } + g.clear(); + g.drawString("logging: " + ((pulsecount/6)*100).toFixed(0) + "%", 120, 120); + } + if(pulsecount == 6) + turn_off(); + pulsecount++; + } +});