A flow meter is disclosed. The flow meter can include a housing that has a cavity. The flow meter can also include a deformable tube that is disposed in the cavity. The deformable tube can comprise a portion of a flow path of a fluid substance. The flow meter can further include a cam that is rotatably coupled to the housing. A portion of the cam is configured to press against a portion of the collapsible tube so as to deform the portion of the collapsible tube. The cam can be configured to rotate in response to a flow of the fluid substance in the flow path.