Improving the energy characteristics of optical measurement chanel of digital portable spirometer

The purpose of the paper: reducing the power consumption of the optical measuring channel and the quantify of its impacting on the parameters of turbine flow transducer spirometer are considered. In the work the studying of channel transmission characteristics and its dependence on the most common external factors were carried out. The methods: the paper proposed and implemented a new functional scheme of optical transducer based on digital portable spirometer DSP-14/1. The research adjusting optical characteristics of measuring channel and its dependence on external interferences such as changing light room and the appearance of condensation on the surface of the turbine during exhalation is carried out. The results: the main consumer of energy in the digital portable spirometer serves a turbine flow transducer. The dependence of LED power of the control signal has a parabolic character. The saturation of parameters of pulse sequence and moment of extinction pulses reach earlier with increasing ambient light intensity. The investigation of condensate impact in three points on the operating range of the control system was conducted. The slight change of level of additional constant component, which over time increases its value, was discovered. The conclusions: The research of transfer characteristic of optical channel performance revealed areas where power consumption of optical channel is significantly reduced. The results can be used to develop control algorithm of automatic optical measuring channel, reduce the power consumption of portable spirometer and increase operation time