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11. Ultrasonic follow

Ultrasonic follow

Ultrasonic follow1. Software-Hardware2. Brief principle1. Hardware schematic diagram2. Physical connection diagram3. Control principle3. Main functions4. Experimental Phenomenon

This tutorial is a comprehensive experiment combining multiple peripherals. You can first understand a single peripheral before performing this experiment.

1. Software-Hardware

STM32F103CubeIDE
STM32 Robot Development Board
Ultrasonic module, 310 motor*4: external
Type-C data cable or ST-Link
Download programs or simulate the development board

2. Brief principle

1. Hardware schematic diagram

2. Physical connection diagram

Ultrasonic Installation

Motor Wiring


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For battery pack assembly, please see [5. Smart Car Experiment: Car Line Patrol]

3. Control principle

The distance of the object in front is obtained through the ultrasonic module, and the car is controlled to move forward and backward according to the distance.


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The ultrasonic module can obtain the distance of the object in front, and we judge the position of the car based on this distance:
If the car is close to the object, we call the car's backward function in the corresponding judgment function;
If the car is far away from the object, we call the function of the car moving forward in the corresponding judgment function;
If the car happens to be at the distance we set, we call the car stop function in the corresponding judgment function.

Program flow chart

External modules	Functions
Ultrasonic module	External information collection: Obtain object distance
Motor	Motion Control

3. Main functions

This tutorial does not use PID to control the movement of the car


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The functions introduced before will not be introduced again!

Function: Ultrasonic_follow

Function prototype	void Ultrasonic_follow(uint16_t Max_distance,uint16_t Min_distance)
Function description	Ultrasonic following
Input parameter 1	Max_distance: follow the maximum distance
Input parameter 2	Min_distance: follow the minimum distance
Return value	None

Function: Get_distance

Function prototype	float Get_distance(void)
Function description	Ultrasonic ranging
Input parameters	None
Return value	Distance (five times average)

Function: wheel_State

Function prototype	void wheel_State(uint8_t state, uint16_t speed)
Function description	Control car movement
Input parameter 1	state: Car status
Input parameter 2	speed: speed control
Return value	None


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For the underlying driver, you can refer to the tutorials in Chapter 3 and Chapter 4.
For the application layer, you can read the source code in the project file yourself

4. Experimental Phenomenon

After successfully downloading the program, press the RESET button on the development board to observe the effect of the car!


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For program download, please refer to [2. Development environment construction and use: program download and simulation]

Phenomenon:

Hand close to the ultrasonic module: The car moves backwards

Hands away from the ultrasonic module: The car moves forward. When the distance exceeds the maximum following value, the car stops.

Keep your hand within the following distance: The car will move forward first and then stop.


You can see the experimental phenomenon [Ultrasound Follow_Experimental Phenomenon.mp4]

Car line patrol

Ultrasonic obstacle avoidance