Vital sign sensor apparatuses which measures vital signs based on arterial pressure waveforms are described. In some embodiments, the apparatus includes an infrared sensor configured to capture at least a portion of an arterial pulse pressure waveform from a user. The apparatus further includes a processor configured to determine a maximum point for each of a plurality of peaks of the arterial pulse pressure waveform, and a corresponding first timestamp. The processor also determines one or more vital signs (e.g., a heart rate for a user, a heart rate variation of the user, a respiration rate of the user, and/or an arterial pulse pressure of the user) based at least in part on the plurality of maximum points and the plurality of corresponding timestamps. Related systems, methods, and articles of manufacture are also described.