PPG sensor emits light at at least three wavelengths (Y1-Y3) and detects the reflected light. The PPG sensor comprises a motion correction unit (130) for correcting motion artefacts from the detected light signals by subtracting the output signal of the detected light at the second wavelength (Y2) from an average of an output signal of the detected light at the first and third wavelength (Y1, Y3). The three wavelengths (Y1-Y3) are arranged around 550 nm. The second wavelength (Y2) is arranged equal distantly between the first and third wavelength.
