feat(ecg): Super basic ecg log plotter

tools/ecg-plot.py

+# vim: set ts=4 sw=4 tw=0 et pm=:
+import numpy
+import sys
+import matplotlib.pyplot as plt
+
+def read(file_name):
+    signal = numpy.fromfile(file_name, dtype=numpy.int16)
+    return signal
+
+
+signal = read(sys.argv[1])
+factor = -1
+count = 5
+offset = 0
+
+signal = signal[offset * 128:]
+
+count = min(min(len(signal) / 1280 + 1, 10), count)
+
+font = {'family': 'serif',
+        'color':  'darkred',
+        'weight': 'normal',
+        'size': 16,
+        }
+
+title = False
+
+for i in range(count):
+    plt.subplot(count, 1, i + 1)
+    sub_signal = signal[i*1280:(i+1)*1280] * factor
+
+    # pad with 0 as needed.
+    # TODO: find a better solution to visialize this
+    sub_signal = numpy.pad(sub_signal, (0, 1280 - len(sub_signal)), 'constant')
+
+    time_scale = numpy.array(range(i*1280,i*1280 + len(sub_signal))) / 128. + offset
+
+    plt.plot(time_scale,sub_signal, '-')
+    if not title:
+        plt.title('File: %s' % sys.argv[1].split('/')[-1], fontdict=font)
+        title = True
+
+plt.xlabel('time (s)', fontdict=font)
+plt.show()