MSP430 Applicationin based on reversing radar design
source: "information technology" Author: Wen Jixia Zhang Yanbing time: 2012-04-17-
ultrasonic transmitting and receiving part of the software
The distance between the receiver and the judgment method of ultrasonic obstacle and cars, and according to the judgment of the distance to trigger an alarm to work, the working principle of the process is shown in figure 2.1.
The ultrasonic transmitting subprogram task: control the time-base circuit outputs a plurality of ultrasonic, and simultaneously start the T0 start time. In this process, to time used maskable interrupt, disconnected operation, to avoid the influence of effective implementation of the external interrupt subroutine.
The system uses an interrupt, external interrupt INTO is indicating signal ultrasonic effective echo, when the interrupt is triggered, the transmission distance can be calculated according to the time difference of ultrasonic. Internal timer TO used for timing, the emission subroutine starts, start the T0 began to work, and in the INTO interrupt service program, stop the T0 timing, and read the value of time to calculate distance.
The distance is calculated according to the transmission time of the subroutine MSP430 chip counter offer, and according to the propagation distance of ultrasonic calculated. According to the needs of the main program, data will be stored in the relevant unit, for the main program for the next step of processing. INTO interrupt service program timer value in a R1, R0 two registers, according to model numerical value obtained by the time difference minus the disposal. The transmission distance is calculated according to the formula S=V*T. The distance from the object value, also calculate according to the formula, wherein T is the amount of counter measure the timing difference, calculate the object and the vehicle distance units for us. using the formula.
design of
reversing radar based on MSP430
System using ultrasonic in the air can be transmitted, a real-time measurement of ultrasonic propagation in air time and propagation velocity, the multiplication time and speed to obtain the distance principle, a design based on the MSP430 ultrasonic reversing radar monitoring alarm system, used for real-time measurement of the rear of the car and the obstacle distance, through LCD display distance, the distance value provided to the driver, the system has the advantages of low cost, non-contact, fast speed, high reliability, good adaptability, convenient operation, has a broad application prospect.
The practice application shows that, this design has certain value in application and scientific research. A product design man-machine interface more humane, the driver can directly through the LCD display of detailed status after the car, do not need to go back to back, greatly reducing driver workload, avoid the lead car accidentally caused the traffic accident; on the other hand system continuously acquires the distance between the vehicle and obstacles, and the voice alarm system to warn the driver, provides more security for our car, so we in the car when the more convenient, but also more safe and reliable.
