A low-cost but reliable flow and pressure sensor is an impediment to development of medical equipment, and studies of human respiratory function, which is characterised by relatively low pressures and flows. A Venturi tube (D1=15mm,D2=10mm) connected to a differential pressure sensor (SDP816-125 Pa) allows accurate measurement of flow between 5-75L·min-1, with Pearson Correlation over 4 min at 50Hz ⩾0.97, and distance correlation ⩾0.96. The pressure measurement was similarly accurate using a MPVZ4006GW7U. Both sensors provide an analogue output from a 5.0V supply, aiding compatibility and customisation. Each populated PCB costs approximately $50USD, and each Venturi sensor costs approximately $1USD. Multiple configurations exist, allowing flow rates up to 250L·min-1, increased resolution for specific ranges, and different physical characteristics.