An optical flow rate sensor system for a sprayer includes an optical sensor, an optical sensor window within a display housing, a projectile within a drum housing, and vortexing geometry upstream of the projectile. The optical sensor is located adjacent to the optical sensor window. The projectile includes a first section having a first optical absorption value and a second section having a second optical absorption value that is lower than the first optical absorption value. The projectile is configured to revolve around an axis of the drum housing.

After reading the consumption, through a turbine flow meter (7), the data is sent by an RF module (9) to the internet (11), which can be via a data concentrator (10) or directly, depending on the RF module technology to a data server (12) where they are stored and made available to the end user via access to a cell phone application (13) or computer software (14).

A system for measuring a flow rate of a fluid containing liquid includes a body in which the fluid flows, at least one rotor configured to be rotated by the fluid, and a device for measuring a rotation speed of the rotor. The measuring device includes an optical module configured to transmit an incident light radiation on vanes of the rotor, in a direction substantially perpendicular to an axis of rotation of the rotor and receive a reflected light radiation coming from the vanes. The measuring device further includes a conversion module configured to determine the rotation speed of the rotor according to the reflected light radiation and determine the flow rate of the fluid.