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.
