Design and development of CO2 sensor controller using solid electrolyte

This paper focuses on an electrochemical CO₂ sensor controller based on solid electrolyte using electrochemical CO₂ sensor. The controller applied the unique principle of converting a voltage state, which results from electrochemical reaction using a new material (electrode supplementary material) reacting selectively with CO₂ in air, to CO₂ concentration. Because the output of a CO₂ sensor is too small, accurate CO₂ concentration cannot be obtained with an ordinary opamp. We obtained accurate EMF values through experiment using an instrument opamp containing high impedance. In addition, for fast conversion, we sampled the data of the thermocouple, thermistor and CO₂ sensor using software and processed the data using interpolation, which reduced the load of processing by numerical formulae. In particular, a processor internal clock was used to reduce the size of the CO₂ sensor.