| With the rapid development of Internet of things technology,the demand for monitoring systems of electric power,water and gas consumption is increasing day by day.How to collect and apply these data in a timely,effective and accurate way is the business that enterprises like to invest.At present,the wireless meter reading equipment often uses the battery power supply way,how to reduce the meter reading equipment power consumption,lets it have the longer service life,also is the question which needs to solve.Based on the above situation,a low power wireless meter reading data transmission node based on LoRa technology was designed and implemented in this thesis.Through analyzing the factors that affect the power consumption of data transmission nodes in wireless meter reading system,the power consumption of nodes is reduced from two aspects of hardware and software.By selecting low power STM8L151K4 microcontroller chip and RF chip SX1278 based on LoRa technology to ensure the node low-power comsumption;software using node power control technology,transmit power based on link state regulation to reduce the power consumption of network nodes.Secondly,the dynamic centralized polling TDMA protocol is used to solve the problem of energy consumption due to the competition channel when the data is transmitted between nodes.In order to reduce power consumption further,the improved asynchronous wake mechanism is adopted to improve the power consumption by increasing the sleep duration of the acquisition cycle and decreasing the duty cycle of the monitor/hibernate.Finally,the hardware and software of the node are designed and implemented.After testing,the node hardware dormant power 21.75uW,power transmission and reception mode for 410.4m W and 51.9mW,a single reading success rate higher than 99%,the total success rate was 99.3%,no node in the obstacle condition,wireless transmission can achieve 3105.5m.The test meets the requirements,and can be widely used in wireless meter reading project. |
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