This application relates to a portable electronic device including a first sensing module and a second sensing module that are both in communication with a processor. The portable electronic device can include access ports that are formed in the housing, where the first and second sensing modules are capable of receiving an external stimulus by way of the access ports. A plate is positioned in the housing between a wall of the housing and the sensing modules. The plate and the wall define non-linear flow paths between the access ports to the first and second sensing modules. The non-linear flow paths can transmit the external stimulus to cause at least one of the first or second sensing modules to provide a detection signal to the processor that causes a display unit to present a notification that corresponds to the external stimulus.