Design Of Wireless Data Acquisition System Based On Micro Hotplate Gas Sensors

Wide range sensors'application has become a trend with the fast development of Internet of things. For gas sensor applications gas sensor node should have the advantages of low power consumption, high stability and networking properties. This paper have taken fully advantages of low power consumption and rapid thermal response of micro hotplate also considered the demand of Internet of things'application, temperature-controllable data collection network system has been developed. It consists of wireless gas sensor node, computing server, database, web server and mobile terminal. This system has the power of data acquisition, sensor temperature control, data processing, cross platform data access, data visualization.This paper uses CC3200 integrated Wi-Fi chip to design two kinds of heating nodes, one of them is DC heating node, the other is pulse heating node. In order to enhance the sensors stability under different environmental conditions, this paper develops a remote temperature control function. Using TI code composer studio we develop an embedded software for the nodes which realizes the functions of automatic network, automatic acquisition and temperature control. The system using MATLAB software environment to construct real-time data acquisition and processing software on computing server. Also using MySQL database construct historical sensor database. At the web server, this paper designs a website using HTML5, CSS and JavaScript which unities the access pages from different terminals and have remote control ability. A PHP software is designed for MySQL data downloading. At last, this paper designs an Augment Reality application for sensor data visualization.The temperature control ability and the functions of system were tested. The test results show that the two temperature control nodes have better stability than the constant voltage heating. The system can dynamically manage the state of the network node, adjusting the sensor nodes temperature, and insert data into database in real time through the web server from the Web page. Through the virtual reality the system achieves a direct reading of the sensor nodes through the marker icon in real time.