Controller and a method to determine a swim stroke

A method for determining a swim stroke of a swimmer, the method comprising:

• receiving, with a processor, an input signal from at least one accelerometer, the processor being operably connected to a non-transitory memory storing program instructions that implement a filter module and a stroke segmentation module;
• filtering the input signal using the filter module with the processor;
• determining, using the stroke segmentation module with the processor, at least two parameters comprising a first parameter and a second parameter from the filtered input signal, the first parameter being local minima of peaks in the filtered input signal, the second parameter being a relative amplitude of the peaks, the relative amplitudes being differences between the local minima of the peaks and local maxima of the peaks;
• generating, using the stroke segmentation module with the processor, an envelope signal using the at least two parameters and the filtered input signal, the envelope signal coinciding with the local maxima of the peaks and decaying between the local maxima of the peaks;
• and
• determining, using the stroke segmentation module with the processor, the swim stroke of the swimmer based on the filtered input signal and the envelope signal.