Methods, Systems and Devices for Measuring Fingertip Heart Rate

A heart rate monitor comprising:

• a light source;
• a light detector disposed to receive light emitted from the light source and reflected from a blood vessel disposed within in a heart rate monitor subject;
• a display screen;
• and
• a processor coupled to the light source, the light detector and the display screen, the controller including memory and processor including computer executable instructions for:
• detecting a plurality of heart beats in the light received in the light detector within a sampling time period including measuring a baseline reflectance signal of the light reflected from the blood vessel between each one of the heart beats and for detecting a second reflectance signal corresponding to at least one heart beat in the blood vessel, the second reflectance signal being less than the baseline reflectance signal, where the blood vessel scatters more of the light during the at least one heart beat than between each one of the heart beats;
• estimating a first estimated heart beats per minute corresponding to the plurality of heart beats detected in the sampling time period;
• estimating a second estimated heart beats per minute, wherein the second estimated heart beats per minute is greater than the first estimated heart beats per minute;
• estimating a third estimated heart beats per minute, wherein the third estimated heart beats per minute is less than first estimated heart beats per minute;
• scoring the first estimate of heart beats, the second estimate of heart beats and the third estimate of heart beats;
• selecting a highest scoring of the first estimate of heart beats, the second estimate of heart beats and the third estimate of heart beats;
• and
• outputting the selected estimated heart beats per minute to the display screen.

An activity tracking device, comprising,

• a housing, the housing including:
• a motion sensor and a processor, the processor configured for processing motion data produced by the motion sensor;
• a display screen integrated with the housing to display metrics that quantify the motion data produced by the motion sensor;
• a light source integrated within the housing to enable light to be directed out of the housing at a heart rate monitor location on the housing;
• and
• a light detector integrated within the housing, the light detector configured to capture an amount of the light that is reflected back to the light detector, at least a first portion of the light reflected back to the light detector is reflected from a blood vessel disposed under a skin of a user when the user places the skin over the heart rate monitor location on the housing, the processor further being in communication with the light detector to enable processing of the reflected light, the processing configured to identify heart beats of the user and produce an indication of a heart rate, the indication of the heart rate being displayable on the display screen as an option, in addition to the metrics that quantify the motion data, wherein the heart rate is calculated based on an algorithm that:
• calculates a first estimate of heart beats per minute corresponding to detected plurality of heart beats in the light received in the light detector within a sampling time period;
• calculates a refined estimate of heart beats per minute;
• and
• identifies and filters at least one falsely detected heart beat coinciding with motion detected by the motion sensor.