Earphones with biometric sensors are disclosed. In addition to wirelessly receiving audio data for playback, the disclosed earphones collect the users biometric data such as heartrate data and movement data, and wirelessly transmit the biometric data to a computing device for processing and user-interaction using an activity tracking application. The biometric earphones may include a battery a circuit board electrically coupled to the battery a processor electrically coupled to the circuit board a pair of earphones a controller and a cable electrically coupling the earphones to the controller. One of the earphones includes an optical heartrate sensor electrically coupled to the processor, and protruding from a side of the earphone proximal to an interior side of a users ear when the earphone is worn and a motion sensor electrically coupled to the processor. The processor processes electronic input signals from the motion sensor and the optical heartrate sensor.
