Abstract
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 = 15 mm, D2 = 10 mm ) connected to a differential pressure sensor (SDP816-125 Pa) allows accurate measurement of flow between 5 - 75 L · min-1 , with Pearson Correlation over 4 min at 50 Hz ⩾ 0.97 , and distance correlation ⩾ 0.96 . The pressure measurement was similarly accurate using a MPVZ4006GW7U. Both sensors provide an analogue output from a 5.0 V 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 250 L · min-1 , increased resolution for specific ranges, and different physical characteristics.