Mid-infrared absorption-spectroscopy-based carbon dioxide sensor network in greenhouse agriculture: development and deployment

Abstract

A mid-infrared carbon dioxide (CO₂) sensor was experimentally demonstrated for application in a greenhouse farm environment. An optical module was developed using a lamp source, a dual-channel pyre-electrical detector, and a spherical mirror. A multi-pass gas chamber and a dual-channel detection method were adopted to effectively enhance light collection efficiency and suppress environmental influences. The moisture-proof function realized by a breathable waterproof chamber was specially designed for the application of such a sensor in a greenhouse with high humidity. Sensor structure of the optical part and electrical part were described, respectively, and related experiments were carried out to evaluate the sensor performance on CO₂ concentration. The limit of detection of the sensor is 30 ppm with an absorption length of 30 cm. The relative detection error is less than 5% within the measurement range of 30-5000 ppm. The fluctuations for the long-term (10 h) stability measurements on a 500 ppm CO₂ sample and a 2000 ppm CO₂ sample are 1.08% and 3.6%, respectively, indicating a good stability of the sensor. A wireless sensor network-based automatic monitoring system was implemented for greenhouse application using multiple mid-infrared CO₂ sensor nodes. A monitor software based on LabVIEW was realized via a laptop for real-time environmental data display, storage, and website sharing capabilities. A field experiment of the sensor network was carried out in the town of Shelin in Jilin Province, China, which proved that the whole monitoring system possesses stable sensing performance for practical application under the circumstances of a greenhouse.

Development and Measurements of a Mid-Infrared Multi-Gas Sensor System for CO, CO2 and CH4 Detection

“…The development of multi-gas detection technology plays an important role in many areas, such as environmental atmospheric monitoring [ 1 , 2 ], medical diagnosis [ 3 , 4 ], industrial process control [ 5 , 6 ], gas monitoring and fire alarm systems in coal mines [ 7 , 8 , 9 , 10 ]. So far, the most widely used technology for multi-gas instruments is photo-acoustic spectroscopy (PAS) and catalytic reaction.…”

Theoretical Research on Ellipsoidal Structure Methane Gas Detection Based on Near Infrared Light Sources of PbSe Quantum Dots

“…Existing methods for methane detection rely mostly on vector catalytic combustion, thermal conductivity, optical interferometry, and infrared absorption. Among various available methods, infrared spectroscopy absorption has its unique advantages over the other techniques [5,6]. The sensing parts of infrared spectroscopy absorption gas detection system include an infrared launch system, a gas chamber, and a photoelectric conversion device.…”

Multi-Layer Aperiodic Dielectric Stack Structures for High Performance Electromagnetic Spectral Shaping from mm-Wave to mid-IR Frequencies

“…Due to the periodic nature of this device, the response is also expected to be periodic. Expanding the spectral sweep to f ∈ [40,80] GHz, this periodicity is demonstrated in Fig. 2.19(a) as opposed to the suppressed periodicity shown in the performance of the aperiodic structure in Fig.…”

“…For example, mid-IR optical devices have important applications, one of which is sensing of a wide variety of gases such as carbon dioxide (CO 2 ) and sulfur dioxide, (SO 2 ), with work demonstrating this application [31,32,33,34,35,36,37,38,39,40,41,42,43]. In this work, a direct thermal testing of an aperiodic all-dielectric stack is performed, with its high-Q characteristics being experimentally verified, where samples are heated to produce the mid-IR emission at around 71 THz, being near to the absorption peak of CO 2 .…”