Peristaltic pumps are described herein. In certain embodiments, a peristaltic pump includes a plunger and a feeler pin. The plunger is movable to selectively engage a pumping volume of a tubing segment to expand the pumping volume to draw fluid flow into the pumping volume and to contract the pumping volume to conduct fluid flow from the pumping volume. The feeler pin extends through the plunger and movable to maintain contact with the tubing segment, wherein the feeler pin is movable in response to a height of the pumping volume.