A device for monitoring arterial blood flow includes: a carrier substrate positioned on or affixed to a users body an array of light emitting elements on the carrier substrate, in which each light emitting element is arranged to emit light into the user when the carrier is positioned on the users body an array of light detecting elements on the carrier substrate, in which each light detecting element is arranged to detect light generated by one or more of the light emitting elements after the light has reflected from an object within the users body and an electronic controller to discretely activate one or more of the light emitting elements while simultaneously deactivating one or more other light emitting elements in the array, receive a signal generated by at least one light detecting element, and determine, based on the received signal, a condition of the users body.
