What is the composition and working mode of the ultrasonic sensor in SmartCAR2.0?

The working mode of SmartCAR2.0 ultrasonic sensor

    The ultrasonic sensor in SmartCAR2.0 has a receiving part and a transmitting part on a board. The transmitting part sends ultrasonic waves, and the receiving part receives the data reflected from the obstacle. According to this ultrasonic sensor to detect obstacles and realize autonomous search. This chapter will continue to share the composition and working methods of the ultrasonic sensor in SmartCAR2.0.

    According to this ultrasonic sensor to detect the obstacle, the ultrasonic wave sent by the transmitter is reflected on the obstacle, and the distance of the obstacle can be known by calculating the return time. Ultrasonic sensors are mounted on the front and back of the vehicle-shaped robot. When the robot moves forward or backward, all obstacles in the front and back can be detected. The following table shows the specifications of the ultrasonic sensors installed on the vehicle-shaped robot SmartCAR2.0.

Table 11-2-1|Specifications of SmartCAR2.0 Ultrasonic Sensor

    The two TXD lines of the transmitter are driven by the ultrasonic sensor, and 40KHz signals are transmitted to each other while driving the transmitter of the ultrasonic sensor. Therefore, the signal generated by the transmission to the AT91SAM3X8EA is transmitted to the transmitting unit, and the ultrasonic sensor in the transmitting unit emits ultrasonic waves. There are also signals reflected in the receiving unit to calculate whether there are obstacles before and after the obstacles, and to detect where the obstacles are.

    In other words, the inverted 40KHz clock in the TXD line of the 2 lines of the ultrasonic sensor will be given 7-8 times. The waveform at this time is amplified by the RS232 level by UART (MAX232), and the ultrasonic wave request transmission is transmitted in the ultrasonic sensor transmitting module. The ultrasonic sensor emitted by the reflection of the obstacle is transmitted to the receiving part. The waveform received in this sensor is amplified by OP (amplifier), and the waveform generated by analyzing the voltage is transmitted by AVR. The following figure is the related circuit diagram of the ultrasonic sensor equipped on the car-shaped robot.

    Through ATmega16U2 and mainMCU (AT91SAM3X8EA) communicate through the serial port, confirm the definition value.          The ultrasonic sensor installed in SmartCAR2.0 of the car-shaped robot can measure the distance within 4cm~50cm, and the measurement outside this distance will cause the error of the sensor value.

    Ultrasonic sensors are equipped with 3 forward sensors on SmartCAR2.0, 2 rear orientation, and 1 ultrasonic sensor on the left and right sides. At the same time, SmartCAR2.0 has a lithium battery power detection function.

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