Carbon dioxide (CO₂) is produced during the fire smoldering process; thus, a fire alarm system based on non-dispersive infrared (NDIR) is employed to monitor the CO₂ concentration to prevent fire accidents. Using the fundamental absorption band of CO₂ molecules at 4.26 μm and mid-infrared absorption spectroscopy, the early fire alarming system uses an infrared broadband heat source and dual-channel pyroelectric detector to achieve highly sensitive CO₂ detection. Using prepared CO₂ gas samples, the sensor characteristics of the CO₂ sensor system are studied. Early fire alarm system must work with agricultural machinery; thus, the sensor must be damped. Based on the model and application of the Duhamel integral in solving vibration system response, a vibration damping module is designed, and the damping structure is modeled and simulated. The results demonstrate that the vibration amplitude is reduced by 82%. The outdoor vibration test of the damping module demonstrates that, when using the damping module, the vibration amplitude of the instrument is reduced by 86%-87%, and the measurement variance of CO₂ concentration is reduced by 50.01% and the uncertainty is reduced by 29.52% compared to the case when the damping module is not used. Simulation analysis and outdoor vibration experiment results demonstrate that the damping module provides good vibration reduction effect with the advantages of high cost-performance, simple vibration reduction structure, etc., and is of obvious value in engineering applications.