Low Cost Visual Humidity And Temperature Control System Based On ARM

With the development of the internet and communications technology, through nearly 20 years development, Embedded-system entered a new historical stage: it comes from low-end to high-end in more and more applications.The sign is the 32 MCU has been used currently in recent years. Under the participation of more MCU manufacturers, the 32bit MCU based on ARM system will be applied widely in more fields. And this has been the main trend.The automatic-measure and the records display of temperature and humidity is one of the conventional monitoring projects in the factory. In the past, people collected data themselves. In this way, it needed much human resource with low reliability. Of course error is easy to happen. So this way was not fit to the requirements of industrial production. General temperature and humidity collection system display data monotonous and short of history data. Many of these system also don't support the communication with most of PLC. Furthermore, temperature and humidity collection module is difficult to layout as too many lines. It is restricted by the placement of plant also.This paper utilizes 32bit ARM micro-processor 'ARM926EJ-S' as the core of the platform to buildup system,which is applied widely at present. Main controller collects the data from sensors and display them in the LCD. At the same time it will exchange the date through RS485 with PLC. The main controller has a 5.7 inch STN LCD with 16 grayscale. It also has a resistor touch panal for human interface friendly.The humidity and temperature collection module uses AVR MEGA88 as the controllor. SHT10 is a single chip relative humidity and temperature multi sensor module which comprising a calibrated digital output. It collect temperature and humidity data outside accurately. And then, the data are sent back to main controller through wireless radio frequency transceiver nRF905.The hardware design of this item includes: design spec, part selection and Schematic drawing for main controller and temperature and humidity collection module, design PCB board, debug.