The invention discloses an exhalation measuring module, which may comprise a housing, a turbine and an electromagnetic converter. The housing may be formed with a receiving space connecting to an inlet and an outlet for passing an exhalation flow from the inlet to the outlet. The turbine may comprise a plurality of magnetic vanes, which are capable of rotation under the exhalation flow. The electromagnetic converter, positioned near the turbine, may generate electrical signals representing rotational motion of the magnetic vanes. The electrical signal may be outputted by the electromagnetic converter for estimating volume of an exhalation.