ABSTRACT
In clinical treatments, reliable flow rate measurements ensure accurate drug delivery during infusions, precise gas delivery during artificial ventilations, etc., thereby reducing patient morbidity and mortality. However, precise flow rate sensors are costly, so medical devices with limited budgets choose cheaper but unsatisfactory flow rate measurement approaches, leading to increased medical risks. Here, a photoelectric flow rate sensor based on a flexible planar curved beam structure (FPCBS) is proposed. The FPCBS ensures low out-of-plane stiffness of the sensitive sheet and allows large deformation in the elastic range, enabling the flow rate sensor to measure the flow rate with high sensitivity over a wide range. Meanwhile, the flow rate sensor can be mass-produced using mature materials and manufacturing technology at less than $5 each. The flow rate sensors are integrated into a commercial infusion pump to measure drug infusion and a home ventilator to monitor respiration. The results are comparable to those measured by a commercial flow rate sensor, demonstrating the applicability of the sensor. Considering its proven outstanding performance at low cost, the flow rate sensor shows great potential in clinical treatment, medical diagnosis, and other medical fields.