Irrigation flow sensor systems and methods of detecting irrigation flow

Some embodiments provide an irrigation flow sensor system, comprising: a housing forming a fluid channel to cooperate with conduits of an irrigation system; a paddle wheel device with at least a first blade of a set of the blades comprises a magnetic element; the paddle wheel device is positioned with at least a portion of the blades extends into the fluid channel as the blades rotate about an axis; a magnetic sensor proximate a pathway of the magnetic element as it rotates configured to provide a sensor output every time the magnetic element passes the magnetic sensor; a switch coupled to the magnetic sensor and a current loop, wherein the switch in an activate state is configured to temporarily change the current in the current loop in response to the sensor output, with a rate of change in current corresponding to a flow rate of the fluid flowing.