CO_2 Gas Detection Device Design Based on TDLAS Technology for Agricultural Environment

摘要

At present, the electrochemical mode is extensively adopted for carbon dioxide gas monitoring sensors in agricultural fields covering agricultural greenhouses, fruits gardens and flower gardens in China, but it has defects like easy ageing, short lifetime, slow response, low precision and requirement for calibration. In this paper, a gas detection device based on the spectrum absorption mode of TDLAS is designed. DFB laser with the wavelength of 1572.3nm is set as the light source of CO_2 gas detection, and the detection sensitivity of the system is improved through wavelength modulation technique and phase locked amplifier technology. With advantages including fast response speed, long lifetime, high precision and no need for calibration, it can effectively solve the above problems. The test and study show that this device does not need pre-sampling. According to the field survey, distortion will not easily happen to gas information. Automatic calibration is realized for timing, and manual calibration is not required. Moreover, the response time is short. In this way, it has a very extensive application prospect in the aspect of real-time detection for gases like carbon dioxide during agricultural production.