非分散红外二氧化碳检测仪研制

Carbon Dioxide Detector Based on Non-Dispersed Infrared Principle

设计一种电调制、一体化的二氧化碳体积分数检测系统.该系统基于CO2气体分子对红外光的特征吸收和Lambert-beer定律,采用双通道设计,由热释电传感器检测到的两路信号经过1 Hz低通放大电路处理后,输入示波器显示.为了避免光源波动对测量结果的影响,采用5V稳压电路驱动红外光源,单片机对其进行1Hz亮灭调制.对两路输出信号进行计算,可得CO2体积分数.结果表明:检测仪量程为0%80%,响应时间小于1.5s.

A compact nondispersed infrared CO2measuring system using electrical modulated infrared source is designed.The system uses dual channel pyroelectric sensors to detect CO2molecular based on characteristic infrared absorption and Lambertbeer low.Two channels signals detected from pyroelectric sensor are filtered by1Hz low pass amplifier circuit.The measured result is displayed on an oscilloscope.In order to avoid measurement result is affected by light source fluctuation,the infrared light source is powered by5V voltage regulator circuit,and it is switched on and off with1Hz modulation frequency controlled by a single chip.The volume fractions of CO2is obtained according to the calculation of the tow output signal.Result shows that the detector has the measurement rang of0%80%,the response time less than1.5s.