An acoustic means for rendering key respiratory measurements accessible to hand-held mobile digital devices with audio input capabilities (such as mobile phones, personal digital assistants, mobile gaming platforms, and tablets). One or more embodiments comprise: a compact and portable whistle (101) that encodes a users expiratory airflow rate as audio frequency, and a software process with local or remote access to mobile-device audio that decodes said audio frequency to regain expiratory airflow rate and derive key respiratory measurements, so that these measurements and related information may conveniently be made available to the user (100) and the users health network of family members (103) and physicians (104). Embodiments enable leveraging the ubiquity and extensive capabilities of hand-held mobile digital devices, while simultaneously simplifying requirements for a dedicated spirometry device.
