A flow measurement assembly includes a coupler and a flow channel. The coupler maintains a magnet and a sensor spaced from the magnet. The flow channel is positionable between the magnet and the sensor. The flow channel includes a housing having an inlet, an outlet spaced from the inlet, and a flow conduit fluidly open to the inlet and the outlet. A ferrous body is movably disposed in the conduit. The sensor is configured to detect a frequency of a change within a magnetic field as the ferrous body travels within the flow conduit between the magnet and the sensor.
