Accelerometer-Based Automated Counting of Ten Exercises without Exercise-Specific Training or Tuning

Figure 1

The data from the smartphone accelerometer is analyzed by applying three different counting methods. The 3-axis accelerometer reading is converted to a magnitude and processed further by (top) counting when the function crosses a threshold (middle) (threshold crossing) but after smoothing the magnitude (bottom) using the frequency indicated by a peak in the Fourier analysis to estimate count over time.