Patent ID: 11937904
Assignee: APPLE INC.
Field: Medical technology (Instruments)
Classification: CPC A | IPC A

Claim 17:
18. A system for improving performance of a wearable device while recording a cardio machine activity, the system comprising:
a motion sensing module configured to collect motion data of a user of the wearable device;
a heart rate sensing module configured to measure heart rate data of the user, wherein the heart rate sensing module comprises a photoplethysmogram (PPG) sensor and the PPG sensor is configured to be worn adjacent to the user's skin; and
a processor circuit in communication with the motion sensing module and the heart rate sensing module, the processor circuit configured to execute instructions causing the processor circuit to:
begin recording of the cardio machine activity;
determine rotational data from the motion data, the rotational data describing a position of the wearable device in a three dimensional space relative to a frame of reference;
estimate a device heading based on the rotational data;
track the device heading at multiple time points during the cardio machine activity to estimate a relative heading;
detect a variable heading by determining that the relative heading exceeds a heading threshold for the cardio machine activity,
detect an end of the cardio machine activity based on the variable heading;
confirm the end of the cardio machine activity based on at least one of the heart rate data or the motion data; and
end recording of the cardio machine activity in response to the confirming.