Design And Implemention Of On-board Diagnostic Based STM32 And Upper Computer Software

In spite of a lot of conveniences that cars bring to people’s life and travel, they can create a lot of serious problems. With the surging of cars, environmental pollution is getting worse, and traffic accidents are also more likely to happen. In order to relieve traffic pressure and environmental pollution, while some take traffic restriction and widening roads measures, others want to resolve these issues by forming good driving habits. In view of the above background, this paper designs on-board diagnostic system based STM32 board diagnostic terminal and use Android phone as upper computer. On-board diagnostic terminal is responsible for collecting and processing vehicle data and upper computer is responsible for displaying vehicle data. Between the On-board diagnostic terminal and upper computer Bluetooth is responsible for transmitting data. The work is as follows in this paper:(1) This article analyse and research the related technologies involved in the on-board diagnosis technology, including the Bluetooth technology, OBD-II technology, SQLite database technology and Android technology.(2) The realization of the on-board diagnosis terminal: In terms of on-board diagnosis terminal hardware, first of all, this article introduces the chip of STM32 L which is used in on-board diagnosis terminal. Second, this article completes the design of hardware circuit which includes MCU system module, power module, Bluetooth module, real time clock module, SD module and EST527-miniS module. This article also completes the design of hardware PCB. In terms of on-board diagnosis terminal software, first of all, this article completes each module drive and initialization; second, this article completes data processing and data transmission of the on-board diagnosis terminal.(3) The realization of Android client: first of all, this article completes the design of the SQLite database which includes the creation of the database and the design of database table and the operation of database. Then, this article designs mobile phone Bluetooth program. The design of the phone Bluetooth program mainly includes the Bluetooth development process and data processing after data received. Finally, this article completes the design of user functions and interfaces. User functions include user login, user registration, password changes, driving habits, driving detection, the real time data of driving, the early warning of driving.The design has been tested on-board diagnosis terminal and upper computer many times, the test results show that the design of on-board diagnosis system is stable, friendly interface to operate and able to complete the intended function.