Shen Jin

A Remote Measurement and Control System for Greenhouse Based on GSM-SMS

A remote measurement and control system of large-scale greenhouse was developed based on GSM-SMS. The whole system consists of a central station and base stations. The central station is composed by a PC server along with its application software, the GSM module, and the database system. The base station consists of a microcontroller, sensors, the operation administer, and GSM module. Modularization is adopted in the design of the system hardware; and the software exploitation is realized by embedded operating system, all of which make the system easy to be extended, maintained and transplanted. The remote monitoring system can also realize remote real-time data analyzing and processing.

Design of weighing transmitter in corn yield measurement system

To reduce the interference and improve the weighing precision, a kind of weighing transmitter based on MSP430 Micro-Controller Unit (MCU), which is applicable to resistance strain sensor, is designed for corn yield measurement system and its hardware diagram and software design are given in detail. The design takes full advantage of 24-bit Analog to Digital Converter (ADC) ADS1232 to sample the output of weighing transducer, and weighted average method is used to process data. By comparing the results derived from weighted average method and arithmetic average method, it prove that the former is superior to the latter.

Remote Monitoring System of Power Network Based on Virtual Instrument and Wavelet Transform

This remote monitoring system of power network was developed by using the virtual instrument technology, network technology and database technology. The basic structure of the system is Browser/Server mode. Through Internet Explorer, remote client can browse the real-time monitoring data of power network, such as frequency; power factor; virtual value of voltage and current, etc. In the system, the wavelet transform was applied to virtual instrument by using the MATLAB script node in LabVIEW, and utilizes denoising method of sqtwolog soft threshold to eliminate the high-frequency noise. The remote storage and query for a large quantity of data in power network monitoring was realized by using ADO in LabVIEW, remote panel technology built-in LabVIEW 7 Express was applied to satisfy the real-time data display of remote monitoring.

Harmonic Analysis System of Power Network Based on Wavelet Transform

The harmonic analysis system of power network was developed based on wavelet transform by using the virtual instrument. The system consists of sensors, signal conditioning circuits, data acquisition and computers. Within the system, the wavelet packet was adopted to analyse harmonics and locate the distortion point by means of the MATLAB script node in LabVIEW, in which the signals were divided into multi -frequency band according to the power signal character, and the frequency band was selected adaptively so as to promote the time-frequency resolution of signals.

High Frequency Inductive Heat Power Supply Based on Microcontroller AT89C52

A high frequency inductive heat power supply consists of high-speed V-MOSFETS was introduced. The frequency and power of the power supply were 1 MHz and 5 kW respectively. A high-speed PLL MM74HC4046 was used for frequency following its track automatically. The rectifier of the power supply was controlled by microcontroller. The biggest power was attained when steady and reliability of equipment was guaranteed. The experiment results show that the power supply is feasible.