Biometric sensor for determining heart rate using photoplethysmograph

A method for measuring a heart rate through photoplethysmography, the method comprising:

• obtaining, by a photosensor, a plurality of voltages in response to emitting light into a surface of a human body;
• filtering, by at least one hardware processor, at least one predetermined frequency from the plurality of voltages to obtain a plurality of filtered voltages;
• normalizing, by at least one hardware processor, the plurality of filtered voltages to obtain a plurality of normalized voltages;
• determining, by at least one hardware processor, a plurality of slopes based on the plurality of normalized voltages;
• determining, by at least one hardware processor, a plurality of local minima based on the determined plurality of slopes;
• determining, by at least one hardware processor, a plurality of interpulse intervals based on the plurality of local minima, wherein at least one interpulse interval represents a time between a first local minima selected from the plurality of local minima and a consecutive, second local minima selected from the plurality of local minima;
• determining, by at least one hardware processor, at least one heartrate from the determined plurality of interpulse intervals;
• and
• communicating, using at least one communication interface, the determined at least one heartrate to a display.

A machine-readable medium having computer-executable instructions stored thereon that, when executed by at least one hardware processor, causes a biometric sensor to perform a plurality of operations, the plurality of operations comprising:

• obtaining a plurality of voltages in response to emitting light into a surface of a human body;
• filtering at least one predetermined frequency from the plurality of voltages to obtain a plurality of filtered voltages;
• normalizing the plurality of filtered voltages to obtain a plurality of normalized voltages;
• determining a plurality of slopes based on the plurality of normalized voltages;
• determining a plurality of local minima based on the determined plurality of slopes;
• determining a plurality of interpulse intervals based on the plurality of local minima, wherein at least one interpulse interval represents a time between a first local minima selected from the plurality of local minima and a consecutive, second local minima selected from the plurality of local minima;
• determining at least one heartrate from the determined plurality of interpulse intervals;
• and
• communicating the determined at least one heartrate to a display.