Described herein is a heart pulse monitor (100) that can be worn at the wrist of a user. The heart pulse monitor (100) comprises at least one sensor package (110) connected to processing circuitry (150) for determining the pulse rate of the user from signals detected by each sensor package (110). Each sensor package (110) comprises a first sensor element (120), a second sensor element (130), and a mechanically isolating layer (140) that is positioned between the first and second sensor elements (120, 130). The first sensor element (120) provides a first output signal (125) indicative of the pulse of the user, and the second sensor element (130) provides a second output signal (135) indicative of noise. The mechanical isolating layer (140) isolates the second sensor element (130) from the first sensor element (120) so that, processing circuitry (150) processes both output signals to provide a processed output signal (155), the processed output signal (155) has a good signal-to-noise ratio as only the noise is removed during processing of the first and second output signals (125, 135).
