Development Of Multi-parameter Indoor Environment Auto Monitor

Human spent80%of whole life time indoors. Indoor environmentalquality is closely related to people’s health and work efficiency, so the monitoring ofthe indoor environment has been a subject of importance in the field ofenvironmental monitoring. In order to improving indoor air quality, protect humanhealth and improving work efficiency, the development of an indoor environmentmonitor of low-cost, low power, for the general population, integrated real-timemonitoring of a number of parameters and has the function of exceeding standardalarming is the trend for environmental monitoring.This paper formulated detection objects and their technical specifications ofmulti-parameter indoor environment auto monitor, according to GB/T18883-2002indoor air quality standards. With the detection principles of each parameter, overallscheme of the monitor was designed, and an overall evaluation index of indoorenvironment, comfort evaluation methods, was proposed.The hardware circuit of monitor based on ATmega128embedded MCU,combined with the CPLD sample pretreatment, liquid crystal display together withthe key control function of human-computer interaction to guarantee automatization,intellectualization and real-time of the instrument. Modularized and logic-optimizeddesign was introduced in the software, improved the overall performance of theinstrument.Fluent simulation software was used to simulate standard gas changes over timein gas mask during multi-parameter indoor environment auto monitor calibrationprocess. Dimension of the calibration gas mask was determined. According theverification regulation of each parameters, calibration to the seven indexes of themonitor were done. Based on experimental data, indication error and repeatability ofthe instrument were analyzed.This multi-parameter indoor environment auto monitor solves problems thatindoor environmental monitors on market are of relatively single measuring parameter, poor real-time and low measurement accuracy and so on. Large numberof experimental results show that the maximum indication error and repeatability of7measurement parameters, that CO, CO₂, SO₂, formaldehyde, respirable particulatematter, temperature and relative humidity, are within the allowed range ofverification regulation.