Low-power Research On Wireless Sensors On Ships

To monitor the data sensed by all the instruments in the cabin under complex conditions on board ships,data is mainly transmitted between devices using wired cables.The number of cables will increase as the amount of data increases.The limited space in the ship’s cabin makes wiring difficult and not easy to install.Deploying wireless sensors on ships would be a useful exploration.Wireless sensor networks have many potential advantages in our military technology and applications,such as: easy and fast deployment,good concealment,fault tolerance,etc..However,there are also a number of unsolved problems,as wireless sensor nodes are usually used in a special environment,usually using battery power,and the sensor terminal is relatively small,making it possible to carry the battery size is also not large,the battery energy density is not high,then there is a lack of battery energy supply and other problems.To address the limitations of wired cable data transmission and the inability of batteries to last for long periods of time,it is necessary to study energy saving technologies for wireless sensors.The paper designs a low-power hardware architecture based on a real project,proposes a software energy saving strategy and conducts simulation experiments to verify it.The article first compares the more popular wireless exchange methods and chooses LoRa communication technology.An ultra-low-power STM32L071CBT6 core processor-based hardware module circuit scheme is proposed.The hardware circuit includes an RF module,a sensor module and a power module circuit,all using ultra-low energy devices.The two SX127 Xs have two low-power operating modes,which can be set directly through the SPI port,and are set to sleep mode when not transmitting or receiving.The temperature transmitter of the sensor module is a low-power temperature FST100 transmitter with an overall power consumption of approximately2 mA/3.3V,and the temperature sensor is embedded in an AD7124-8 chip with a low-end power start switch that allows the user to cut off a bridge sensor between conversions,thus ensuring that the system has an absolute power consumption.In the power supply module,we add a switch to the battery and these devices,both LDO regulator modules,which can be switched on and off by an MCU IO port to control the transmitter,thus achieving energy savings.Then according to the workflow of the nodes to collect data,the software aspect of the design was carried out,including time division frequency division energy-saving mode,optimization of energy-saving network protocol,dormant energy saving data collection method.After completing the development of the whole wireless sensor,the prototype of wireless temperature and pressure sensor was developed on the basis of the above hardware and software design.The prototype was tested for wireless communication distance and continuous operation,and was able to obtain real-time data accurately at a long distance without packet loss,and achieved the target of continuous operation time of no less than two years for a single sensor node to meet the design requirements.