Personnel positioning system control module circuit design

Design of positioning card: The positioning module uses STM32 as the main control core. The positioning module uses the ST (STMicroelectronics) STM32WCBU6x chip, which uses a 32-bit ARM Cortex-M3 core; STM32WCBU6x integrates a 2.4GHz IEEE8.2.15.4 compatible transceiver, with 128KB Flash and 8KB RAM , is a high-performance wireless system-on-chip (SoC). The main control schematic diagram is shown in Figure 1.

Figure 1 Main controller schematic diagram

Circuit analysis : This system requires an external MCU to control the data transmission and reception of the module, so the external MCU needs to communicate with the module, and its connection method is the (USART) serial port. The module provides a standard USART interface, its IO level is limited to 2.4~3.6V, and the nominal 3.3V logic level is used. When the module serial port does not use hardware flow control, its transmitting (TX) end is connected to the receiving (RX) end of the external MCU; the receiving (RX) end of the module is connected to the transmitting (TX) end of the external MCU.

Summary : The Zigbee module in the hardware part of the design of this positioning system uses STM32 as the main controller, which improves the work efficiency of the entire system and provides great help for the accuracy of personnel positioning. The Zigbee devices in this solution can be powered by ordinary batteries, and one battery can be used for at least 6 months, which reduces costs to a certain extent. For the discussion of the relationship between communication distance and signal strength, the maximum likelihood estimation method is used to reduce the error.