Research on Intelligent Temperature and Humidity Memory Instrument Based on USB Interface

The instrument uses a single chip relative humidity and temperature multi sensor SHT11 module comprising a calibrated digital output, which can measure temperature and relative humidity of environment at any moment, timely and real time. It displays temperature-humidity value, dew point value, date and time at the same time by lattice graphics LCM (Liquid Crystal Display Module) HGO12864. Temperature-humidity value and relevant time are saved in nonvolatile FRAM (Ferroelectric Random Access Memory) FM31256, which can assure data do not lose after power of system fail. Real-time data or data in FM31256 can be upload PC by USB interface, and then is protracted temperature-humidity history curve or real-time curve by internet applications. It can not only calculate maximum, minimum, average and variance among random measuring period of time but also make further statistics and analysis, report forms printing, and setup basic measure parameters of instrument. Its power supply is 3.6 V Li-battery or 220 V AC. It is low power-consuming, high precision, plug and play and better universal performance.