This is an example recording and analysis of arm swing during normal gait. The recording was obtained with two opals located on each of the two wrists. The external button was used to mark the beginning and end of the analysis period, which was then used to isolate the segment of interest for analysis. The opals were recorded in synchronized logging mode. This could also have been recorded with emeralds, but not sapphires.
The files attached below include the original .h5 file that was created from the raw data recorded by each of the sensors and a .mat file that contains a Matlab data structure that was created from the .h5 file.
The analysis used a principle component analysis on the gyroscopes to identify the principal axis of rotation. The analysis includes a plot of the principal signal, an estimate of the power spectral density, and a spectrogram. The arm swing occurs in this example with a frequency of approximately 1 Hz. The break in the arm swing during the turn approximately 160 s into the analysis segment is clearly visible in both the time domain and time-frequency domain (i.e., spectrogram).
How can I have that 'external button' that fits to the data port?