Abstract: In order to change the status of importing expensive equipment from abroad and fill the gap of no formaldehyde testing chamber domestic, this research developed a control system, which kept ATmega2560 as the core, applies fuzzy control arithmetic to control chamber temperature and relative humidity. The system has high stability and flexibility, and the cost was reduced by one third compared with PLC system. The result showed that the accuracy for temperature could achieve ±0.5 ℃ and that for relative humidity was less than ±3%.

Key words: formaldehyde testing, chamber, control system, microprocessor unit, temperature and relative humidity control