Development Of A Low-power Bluetooth Monitoring System For Pure Electrical Intelligent Car

Due to serious global warming, new energy vehicles become a mainstream trend. Aiming to optimize circuit and operation for the real-time monitoring system of pure electric vehicles, this paper developed a wireless real-time intelligent car monitoring system based on Bluetooth 4.0 and the “Freescale Cup” model B car.The main work is as follows:Hardware circuits design mainly include: LTC2943 and LTC1732 had been used to measure the lithium battery charge and discharge. Using three DS18B20 temperature sensors to measure multiple sites temperature of the single lithium battery. For the measure of intelligent car speed, the EA62-CS3 C Omron encoder had been utilized. The CC2541 module had been used to design Bluetooth 4.0 slave and master for achieving the wireless communication of the intelligent car status data. Two high current half-bridge driver BTN7970 B are used to form a complete H-bridge for driving the RS-540SH-7520 DC motor. Low dropout regulator LM2940 and LM1117 had been utilized to design the power supply circuit of each module. The experimental results showed that the hardware can run normally and realize the design function.The programs design include: The I2 C bus communication program for LTC2943. The single-wire bus program for DS18B20. The PWM driver for RS540 servo motor and TRS-D05 steering engine. Using the structural analysis knowledge of mechanical principles to analyze the Model B car steering mechanical structure, then set up the model of a spacial three bar mechanism, deduced finally the formula for the steering angle θ of model B car by using the steering engine angle γ. The AT command configuration for Bluetooth 4.0 slave and master. The experimental results showed that the program had been debugged successfully and had realized the hardware driving.Software design includes:The serial communication module of battery monitoring, temperature acquisition and vehicle control unit(VCU). Parsing, calculating and displaying the message of the lithium battery data(voltage, current, temperature, power). The message of intelligent car speed and steering angle had been parsed, calculated and displayed. Generating the software installation package. The experimental results showed that the software had been installed and run under windows operating system stably.Software and hardware debugging includes: Monitor of the lithium battery status. PWM drive of the intelligent car VCU. The bluetooth 4.0 wireless communication. Comprehensive debugging of the intelligent car monitoring system. By debugging, the software and hardware can work normally, the intelligent car had been monitored successfully.