Data Acquisition System Based On Android

The data collector is a basic device widely used in industrial and agricultural production and daily life.However,the traditional wired network data collector has problems such as cumbersome wiring,poor mobility,and inconvenient update and upgrade.To this end,this paper combines mobile Internet technology with embedded system technology,and proposes to design a wireless network data acquisition system based on Android.The data acquisition system proposed in this paper has two working modes of continuous sampling and timing sampling,which can realize the functions of conditioning,acquisition,wireless transmission,storage and waveform display of 8 analog voltage signals with a maximum frequency of 128 KHz.The system consists of two parts: the data acquisition end designed with STM32F407 processor as the core and the data receiving end jointly developed by the Android system common hardware platform and APP software.At the same time,the related communication protocols are selected for the wireless WiFi communication,and a dedicated data frame format is designed.In the hardware design of the data acquisition end,the signal conditioning circuit realizes the limiting,low-pass filtering,isolation amplification,differential amplification,proportional amplification and voltage following of the 8 analog voltage signals respectively.The main control circuit is based on the STM32F407 processor.The A/D conversion of the analog signal is realized,and the sampled data is transmitted to the W5500 Ethernet communication circuit via the SPI interface by the DMA method,and finally forwarded to the data receiving end via the WiFi wireless router.In the STM32F407 program design of the data acquisition end,with the STM32 CubeMx software generated STM32F4 library function to achieve the STM32F407 processor main program,initialization program,multi-channel A/D conversion program,DMA interrupt service program,with the help of W5500 Ethernet controller official library Function that implements the Ethernet communication program.In addition,the W5500 Ethernet controller official library function has been improved and optimized to effectively improve the Ethernet data communication rate.The data receiving end is composed of a common hardware platform of the Android system with WiFi function and the APP software designed in this paper.The APP adopts the MVC software architecture mode,and designs three working interfaces: registration login,real-time acquisition and playback acquisition.It designs a multi-user registration login program,Socket communication program,waveform display program,data interaction and processing program,and data storage program.Login registration of multiple users,and data interaction with the data collection end under the TCP/IP protocol communication program of the Socket.And the data acquisition process is controlled by the graphical user interface for wireless control,waveform display,data file storage and Excel table display data.The test results show that the data acquisition system designed in this paper can effectively realize the functions of analog voltage signal conditioning,acquisition,WiFi wireless network transmission,storage,Excel spreadsheet display,real-time waveform display and historical data waveform playback.