The Design Of A Thermal Printing System Based On Bluetooth 4.0

With the development of information technology,the thermal printing solution is widely used in every field of social life.A thermal imaging printing process is closely related to the heating characteristics of the printing head.This printing system requires high performance of real-time computing,so the ARM microprocessor is suitable to be used.Traditional thermal printer with wired communication has many drawbacks of inconvenient cable connection,so,the Bluetooth thermal printer is recently developed.In this paper,based on BLE4.0,a wireless thermal printing system with low cost,high performance and reliability is detailedly studied.Based on the analysis of the thermal printer technology and its evolvement,comparing the pros and cons of mainstream ARM chip applications and each Bluetooth version's technology features,the solution based on ARM Cortex-M3 main logic controller and BLE4.0 wireless communication is proposed in this thesis,proceeding with optimization design of Bluetooth antenna by using simulation software.According to the system's power requirements,comparing the mainstream power supply solutions,the SMPS consisting of TM PFC and LLC resonant converter is proposed.Finally,based on the principle of improving reliability and advantaging software development,the modular programming is used in software design.The tasks in the project consist of hardware design,software design and validation tests.Firstly,the main logic control hardware circuit is designed,including main control chip's power supply circuit,main control chip's interface circuit,driving circuit for stepping motor and print head,key press and display circuit,Bluetooth chip's interface circuit,and the optimization design of the meandered inverted-F BLE antenna is achieved by using simulation software HFSS.Then,the simulation softwares,PSIM and Saber,are used in aiding the SMPS' design and verification.The system software design is finalized into Cortex-M3 microprocessor's control program and Bluetooth 4 master's and slave's programs,including modular programming for Bluetooth data transmission and receiving,character printing,print head and stepper motor driving.Finally,printer performance test and printing tests via Bluetooth communication are implemented.The results show that the system can reliably complete the thermal printing tasks via Bluetooth 4.0 wireless communication.