A flow sensor sub-assembly for sensing flow of a fluidic medicament is disclosed. The flow sensor sub-assembly includes a first spring contact and a second spring contact. The spring contacts are secured to a base that has a circuit for conducting an electrical signal to and from the spring contacts to a microprocessor. The first spring contact is in electrical communication with a first piezo element and the second spring contact is in electrical communication with a second piezo element. The first spring contact has a first contact force against the first piezo element and the second spring contact has a second contact force against the second piezo element, and the first and second contact forces are equivalent. A circuit board for interfacing to a flow sensor having a plurality of piezo elements for transmitting a flow signal indicative of flow of fluidic medicament is also disclosed.