The project consists of developing a functional prototype (Beta) of an innovative reverse occlusion system (Relaxed Expiratory Occlusion Monitor or REOM) allowing effortless measurement of obstruction of the airways in sick lungs at low cost given the relative simple construction of the device compared to existing technologies. The prototype will be validated with mechanical resistance as well as in humans by comparing the resistances with those obtained with the oscillometry system Tremoflo marketed by Thorasys.