Research And Implementation Of Wireless Temperature And Humidity Measurement System

Wireless temperature and humidity measurement system is designed for highprecision temperature and humidity measurement and recording, using wirelesscommunications to achieve data exchange. Based on embedded technology and wirelesssensor network technology, this paper analyzes the requirements of high precision, strongnetwork coverage, stable and reliable operation, and then design the wireless temperatureand humidity measurement system.This design uses Zigbee to achieve wireless communication. Wireless measurementterminal is designed as a basic unit responsible for collecting multi-channel sensor data.Wireless base station is responsible for maintenance and management of the entire network.Wireless base station using AT91SAM9263industrial grade microprocessor as corecontroller, combines with CC2530which supporting for Zigbee application andhigh-capacity SD card storage device for the hardware platform. Wireless measurementterminal’s core controller is low-power microprocessor MSP430F2618, using platinumresistance temperature sensor and humidity sensor HC2-S, equipped with CC2530moduleto join on-site measurement network and upload measurement data. On the software side,we use operating system abstraction layer (OSAL) to realize multi-task resource allocationfor software programming, combined with TI Z-STACK to achieve Zigbee networkapplication development.This paper studies the multi-channel sensor measurement solutions. Based oncomparison of existing measurement circuit, we design a flexible, strong reliabilitymeasuring circuit to achieve high precision. In this paper we use polynomial to fit platinumresistance temperature characteristic curve. In positive temperature range, the use ofnon-uniform sub-fitting calibration strategy can make full use of hardware and softwareresources and improve measurement accuracy.The problem of energy consumption of wireless sensor networks has been studied anddiscussed, we analyze the differences of node energy consumption throughout the network,propose single node energy control strategy and overall energy balance control strategybased on dynamic adjustment mechanism. Finally we conduct simulation verification.This paper has completed the design of wireless temperature and humiditymeasurement system, and produced a prototype. Test and field application show that thedeveloped system meets the design requirements of stability, reliability and measurementprecision.