A micro-electro-mechanical, micro-fluidic flow sensor (14) includes a flow separating element (15) for separating a first portion (24) of a fluid flow (25) from a second portion (26) of the fluid flow. The flow sensor also includes a flow obstructing member (17) disposed in the first portion of the flow for at least partially obstructing the first portion of the flow. The flow obstructing member deflects in response to the first portion of the flow so that a degree of partial obstruction of the first portion of the flow by the flow obstructing member varies in response to the first portion of the fluid flow.