Relying on the perfect Beidou satellite communication positioning system, GPRS communication network and various technical platforms equipped with sensor equipment, it has the measurement of wind, temperature, humidity, pressure and other meteorological parameters and the collection of ocean currents, salinity, chemistry and other required oceans. The research and development of hydrological parameters, target positioning, emergency alert reporting, information transmission, statistical reports and other perfect functions of the reporting equipment have a broader application prospect. This paper presents a two-way communication circuit system design. With low power consumption, miniaturization, rich interface and high reliability, it can provide various functions such as ship positioning, maritime communication, and distress and help, which can improve safety and prevention capabilities, and therefore has important significance to relevant industry authorities. ARM9 processor S3C2440A Based on the ARM920T core, the S3C2440A is a system central processor with 128M SDRAM, 256M NAND FLASH and 16M NOR FLASH to handle the memory consumed by the embedded Linux operating system. S3C2440A integrates MMC/SD card read/write controller, LCD and touch screen interface, 3-channel UART serial port, 1-channel master control and 1-way slave USB interface, 1 IDE interface can be connected to large-capacity hard disk, real-time clock, AC' 97 audio interfaces, up to 130 general-purpose IO ports and many other hardware resources. The S3C2440A's integrated 3-way serial port can be connected to the Beidou satellite communication positioning terminal, GPRS module and wind sensor through an external RS232 level conversion chip. In addition, the ARM9 processor S3C2440A can be connected to a 16-bit ADC via an internally integrated two-way SPI interface, which is connected to sensors for temperature, humidity, salinity, and pressure. The general-purpose IO port of the S3C2440A acts as a digital input detection and output control interface and can be expanded according to user requirements. At the same time, the S3C2440A also meets the needs of scalable applications such as Ethernet controllers, USB peripherals, electronic compasses, current meters, and underwater acoustic transmission. Beidou satellite communication module circuit design The design of Beidou satellite communication module circuit can be developed from three levels of signal receiving, signal processing and function interface display. Correspondingly, the cost-effective Beidou satellite communication terminal is used, and the serial communication circuit and LCD liquid crystal display circuit are designed. Beidou satellite communication module can use UM220 module, which supports Beidou II (BD2) and GPS dual system navigation timing, with small size (only 40 & TImes; 30 & TImes; 3.7mm), low power consumption (only 350mW), high integration, etc. The module has a three-dimensional positioning accuracy of 3m, a speed accuracy of 0.1m/s, and a data update rate of up to 1Hz. The UM220 is also equipped with the satellite control software CDT (Control & Display Tool), which provides a simple graphical user interface for easy control of the satellite receiver and the ability to set up and get the information you need. The Beidou satellite communication module circuit mainly includes UM220 interface, antenna, backup power supply, reset and serial communication circuit. The circuit schematic diagram is shown in Figure 4. The serial port 0 pins TXD0 and RXD0 of the ARM9 processor S3C2440A are connected with the RXD3 and TXD3 of the UM220 to form a serial communication circuit. The pin GPE0 of S3C2440A is connected to the PPS pin of UM220 to receive the PPS signal with adjustable pulse width and polarity of UM220 output. The pin GPE1 of S3C2440A is programmable. Figure 4 UM220 circuit schematic The output pulse width and polarity adjustable event signal is provided to the EVENT pin of the UM220. UM220 power supply pin VCC and GND are connected in parallel with electrolytic capacitor CT1 and ceramic capacitor C1 to filter high frequency and low frequency clutter signals, making UM220 power supply stable and pure, and the voltage peak-to-peak value does not exceed 50mV. The UM220 has a precise timing function. To maintain the system clock, the VBAT pin of the UM220 is connected to a 3V lithium battery via a current limiting resistor R1 and voltage drop diodes D2 and D3. Among them, the diode D3 voltage drop is 0.3V, and the D2 voltage drop is 0.7V to ensure that the VBAT pin of the UM220 is normally powered by the main power supply 3.3V, and when the main power supply is de-energized, it is powered by the backup power supply 3V lithium battery. The GNSS_ANT pin of the UM220 needs to be routed 50Ω on the PCB board to match the antenna impedance, and then externally connected to the Beidou satellite cellular antenna. In addition, the resistors R2, R3 and the capacitor C2 and the diode D1 form a stable low-level reset circuit, and the low-level hold time is greater than 2ms. GPRS module circuit design The measuring instrument mainly relies on the satellite communication network for data communication and positioning. In order to reduce the power consumption and operating cost of the measuring instrument system, the GPRS/CDMA network can be used for remote communication. The peripheral application circuit design of the GPRS module includes a module startup circuit, a data communication circuit, a voice communication circuit, and a SIM card application circuit. The GPRS module can be selected from Siemens MC55. The MC55 is a new generation from Siemens. Figure 5 MC55 circuit schematic The wireless communication GPRS module can quickly and reliably realize data, voice transmission, short message service and fax in the system scheme. The module is compact in structure, light in weight, built-in TCP/IP protocol, and can be easily controlled by AT commands. Access to the network. The GPRS module circuit mainly includes MC55 interface, SIM card circuit, starting power supply and serial communication circuit connected with S3C2440A. The circuit schematic diagram is shown in Figure 5. The RXD1 and TXD1 pins of the S3C2440A serial port 1 are connected to the TXD0 and RXD0 pins of the MC55 to form a serial communication circuit. The MC55 CCGND, CCIN, CCREST, CCIO, CCVCC and CCCLK pins form a SIM card interface, and are connected with filter capacitors C4 and C5. The MC55's power supply VBATT is stepped down by 5V through diode D2. The GPE3 driver of the S3C2440A controls the IGT pin of the MC55 to put it into normal operation mode. The GPE2 of the S3C2440A can detect the pulse signal output from the MC55 RING pin to determine whether the system sleeps into a low power state. In order to generate a synchronization signal when there is GPRS data information transmission, it can be realized by configuring the MC55's SYNC pin to control the LED status indication. When there is data transmission, the SYNC pin outputs a high level to turn on the base of the transistor T1, and the red LED LED1 is illuminated. Aquarium Equipment,Aquarium Air Pump,Submersible Pump,Intelligent Aquarium Lamp Sensen Group Co., Ltd.  , https://www.sunsunaquariums.com
----------------------