In this work we developed a Smart Breath Analyzer device devoted to the tele-monitoring of exhaled air in patients suffering chronic respiratory failure and home-assisted by mechanical ventilation. The device originates from the need for continuous and remote monitoring of the patient during a ventilo-therapy session; monitoring data acquired by sensors are transmitted to the healthcare center by TCP/IP communication through a cloud remote platform in order to check continuously the effectiveness of therapy and/or any state of disease exacerbation. The device was both characterized and calibrated with known concentrations of O2/CO2in laboratory field and in a real condition of exhaled air from an healthy volunteer.