嵌入式-stm32-SR04超声波测距介绍及实战

一:超声波传感器介绍

1.1、SR04超声波测距硬件模块

嵌入式-stm32-SR04超声波测距介绍及实战_第1张图片

1.2、SR04的四个IO口

vcc:提供电源5V
gnd:接地
Trig:是**发送**声波信号的触发器
Echo:是**接收**回波信号的引脚
当TRIG信号被触发时,传感器会发送一定频率的声波信号,该信号被反射后,传感器会接收到回波信号,回波信号的时间差可以用来计算物体与传感器的距离。

1.3、SR04是高电平触发模块

所以默认是低电平
怎么让它发送波?
Trig ,给Trig端口至少10us的高电平
怎么知道它开始发了?
Echo信号,由低电平跳转到高电平,表示开始发送波
怎么知道接收了返回波?
Echo,由高电平跳转回低电平,表示波回来了
怎么算时间?
Echo引脚维持高电平的时间!

波发出去的那一下,开始启动定时器
波回来的拿一下,我们开始停止定时器,计算出中间经过多少时间
怎么算距离?
距离 = 速度 (340m/s)* 时间/2
嵌入式-stm32-SR04超声波测距介绍及实战_第2张图片

二、需求介绍

2.1、SR04超声波测距需求介绍

需求:使用超声波测距,当手离传感器距离小于5cm时,LED1点亮,否则保持不亮状态。

2.2、SR04超声波测距模块接线
Trig — PB6
Echo — PB7
LED1 — PB8
嵌入式-stm32-SR04超声波测距介绍及实战_第3张图片

三:stm32CubeMX实现步骤以及细节

3.1、打开Stm32CubeMX,界面如图

在这里插入图片描述

3.2、选芯片:stm32f103c8t6

在这里插入图片描述

3.3、读芯片引脚原理图

嵌入式-stm32-SR04超声波测距介绍及实战_第4张图片

3.4、先把LED灯设置为高电平模式

3.5、设置时钟

配置时钟频率
在这里插入图片描述

3.6、RCC配置

在这里插入图片描述

3.7、定时器

嵌入式-stm32-SR04超声波测距介绍及实战_第5张图片计数一次代表1us
在这里插入图片描述

Tout就是一次的溢出时间,PSC=71,Tclk=72000 000hz(s),此处ARR=0

3.8、代码自动设置生成的文件

在这里插入图片描述

3.9、图形化最后一步

项目名称:sr04_study

在这里插入图片描述

四:编写业务代码

4.1、在初始化完成的代码之后添加业务代码

第①处增加的代码:编写微秒级函数

//使用TIM2来做us级延时函数
void TIM2_Delay_us(uint16_t n_us)
{
/* 使能定时器2计数 */
__HAL_TIM_ENABLE(&htim2);
__HAL_TIM_SetCounter(&htim2, 0);
while(__HAL_TIM_GetCounter(&htim2) < ((1 * n_us)-1) );
/* 关闭定时器2计数 */
__HAL_TIM_DISABLE(&htim2);
}

嵌入式-stm32-SR04超声波测距介绍及实战_第6张图片

4.2、定义变量

第②处增加的代码

  /* USER CODE BEGIN 1 */
	int cnt;
	float distance;
  /* USER CODE END 1 */

嵌入式-stm32-SR04超声波测距介绍及实战_第7张图片

4.3、主函数:

//1. Trig ,给Trig端口至少10us的高电平
//2. echo由低电平跳转到高电平,表示开始发送波
//波发出去的那一下,开始启动定时器
//3. 由高电平跳转回低电平,表示波回来了
//波回来的那一下,我们开始停止定时器
//4. 计算出中间经过多少时间
//5. 距离 = 速度 (340m/s)* 时间/2(注意单位换算)
(计数1次表示1us) //每500毫秒测试一次距离

第③处增加的代码


  while (1)
  {
    /* USER CODE END WHILE */
		/* USER CODE BEGIN 3 */
					//1. Trig ,给Trig端口至少10us的高电平
		HAL_GPIO_WritePin(GPIOB, GPIO_PIN_6, GPIO_PIN_SET);//拉高
		TIM2_Delay_us(20);
		HAL_GPIO_WritePin(GPIOB, GPIO_PIN_6, GPIO_PIN_RESET);//拉低
		//2. echo由低电平跳转到高电平,表示开始发送波
		//波发出去的那一下,开始启动定时器
		while(HAL_GPIO_ReadPin(GPIOB, GPIO_PIN_7) == GPIO_PIN_RESET);//等待输入电平拉高
		HAL_TIM_Base_Start(&htim2);
		__HAL_TIM_SetCounter(&htim2,0);
		//3. 由高电平跳转回低电平,表示波回来了
		while(HAL_GPIO_ReadPin(GPIOB, GPIO_PIN_7) == GPIO_PIN_SET);//等待输入电平变低
		//波回来的那一下,我们开始停止定时器
		HAL_TIM_Base_Stop(&htim2);
		//4. 计算出中间经过多少时间
		cnt = __HAL_TIM_GetCounter(&htim2);
		//5. 距离 = 速度 (340m/s)* 时间/2(计数1次表示1us)
		distance = cnt*340/2*0.000001*100; //单位:cm
		//2*0.000001表示了发送和接收时间的差值(单位为秒),*100是把米变成厘米
		if(distance < 5)
		HAL_GPIO_WritePin(GPIOB, GPIO_PIN_8, GPIO_PIN_RESET);
		else
		HAL_GPIO_WritePin(GPIOB, GPIO_PIN_8, GPIO_PIN_SET);
		//每500毫秒测试一次距离
		HAL_Delay(500);


  }
  /* USER CODE END 3 */
}

嵌入式-stm32-SR04超声波测距介绍及实战_第8张图片

4.4、main.c总代码,直接复制可用

只有main.c有增加,下面的gpio.c、tim.c等等文件都没有变动

/* USER CODE BEGIN Header */
/**
  ******************************************************************************
  * @file           : main.c
  * @brief          : Main program body
  ******************************************************************************
  * @attention
  *
  * Copyright (c) 2023 STMicroelectronics.
  * All rights reserved.
  *
  * This software is licensed under terms that can be found in the LICENSE file
  * in the root directory of this software component.
  * If no LICENSE file comes with this software, it is provided AS-IS.
  *
  ******************************************************************************
  */
/* USER CODE END Header */
/* Includes ------------------------------------------------------------------*/
#include "main.h"
#include "tim.h"
#include "gpio.h"

/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */

/* USER CODE END Includes */

/* Private typedef -----------------------------------------------------------*/
/* USER CODE BEGIN PTD */

/* USER CODE END PTD */

/* Private define ------------------------------------------------------------*/
/* USER CODE BEGIN PD */
/* USER CODE END PD */

/* Private macro -------------------------------------------------------------*/
/* USER CODE BEGIN PM */

/* USER CODE END PM */

/* Private variables ---------------------------------------------------------*/

/* USER CODE BEGIN PV */

/* USER CODE END PV */

/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
/* USER CODE BEGIN PFP */

/* USER CODE END PFP */

/* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */
	//使用TIM2来做us级延时函数
	void TIM2_Delay_us(uint16_t n_us)
	{
	/* 使能定时器2计数 */
	__HAL_TIM_ENABLE(&htim2);
	__HAL_TIM_SetCounter(&htim2, 0);
	while(__HAL_TIM_GetCounter(&htim2) < ((1 * n_us)-1) );
	/* 关闭定时器2计数 */
	__HAL_TIM_DISABLE(&htim2);
	}
/* USER CODE END 0 */

/**
  * @brief  The application entry point.
  * @retval int
  */
int main(void)
{
		/* USER CODE BEGIN 1 */
		int cnt;
		float distance;
		/* USER CODE END 1 */

  /* MCU Configuration--------------------------------------------------------*/

  /* Reset of all peripherals, Initializes the Flash interface and the Systick. */
  HAL_Init();

  /* USER CODE BEGIN Init */

  /* USER CODE END Init */

  /* Configure the system clock */
  SystemClock_Config();

  /* USER CODE BEGIN SysInit */

  /* USER CODE END SysInit */

  /* Initialize all configured peripherals */
  MX_GPIO_Init();
  MX_TIM2_Init();
  /* USER CODE BEGIN 2 */

  /* USER CODE END 2 */

  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
	
  while (1)
  {
    /* USER CODE END WHILE */
		/* USER CODE BEGIN 3 */
					//1. Trig ,给Trig端口至少10us的高电平
		HAL_GPIO_WritePin(GPIOB, GPIO_PIN_6, GPIO_PIN_SET);//拉高
		TIM2_Delay_us(20);
		HAL_GPIO_WritePin(GPIOB, GPIO_PIN_6, GPIO_PIN_RESET);//拉低
		//2. echo由低电平跳转到高电平,表示开始发送波
		//波发出去的那一下,开始启动定时器
		while(HAL_GPIO_ReadPin(GPIOB, GPIO_PIN_7) == GPIO_PIN_RESET);//等待输入电平拉高
		HAL_TIM_Base_Start(&htim2);
		__HAL_TIM_SetCounter(&htim2,0);
		//3. 由高电平跳转回低电平,表示波回来了
		while(HAL_GPIO_ReadPin(GPIOB, GPIO_PIN_7) == GPIO_PIN_SET);//等待输入电平变低
		//波回来的那一下,我们开始停止定时器
		HAL_TIM_Base_Stop(&htim2);
		//4. 计算出中间经过多少时间
		cnt = __HAL_TIM_GetCounter(&htim2);
		//5. 距离 = 速度 (340m/s)* 时间/2(计数1次表示1us)
		distance = cnt*340/2*0.000001*100; //单位:cm
		//2*0.000001表示了发送和接收时间的差值(单位为秒),*100是把米变成厘米
		if(distance < 5)
		HAL_GPIO_WritePin(GPIOB, GPIO_PIN_8, GPIO_PIN_RESET);
		else
		HAL_GPIO_WritePin(GPIOB, GPIO_PIN_8, GPIO_PIN_SET);
		//每500毫秒测试一次距离
		HAL_Delay(500);


  }
  /* USER CODE END 3 */
}

/**
  * @brief System Clock Configuration
  * @retval None
  */
void SystemClock_Config(void)
{
  RCC_OscInitTypeDef RCC_OscInitStruct = {0};
  RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};

  /** Initializes the RCC Oscillators according to the specified parameters
  * in the RCC_OscInitTypeDef structure.
  */
  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;
  RCC_OscInitStruct.HSEState = RCC_HSE_ON;
  RCC_OscInitStruct.HSEPredivValue = RCC_HSE_PREDIV_DIV1;
  RCC_OscInitStruct.HSIState = RCC_HSI_ON;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
  RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
  RCC_OscInitStruct.PLL.PLLMUL = RCC_PLL_MUL9;
  if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
  {
    Error_Handler();
  }

  /** Initializes the CPU, AHB and APB buses clocks
  */
  RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
                              |RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;
  RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
  RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
  RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2;
  RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;

  if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK)
  {
    Error_Handler();
  }
}

/* USER CODE BEGIN 4 */

/* USER CODE END 4 */

/**
  * @brief  This function is executed in case of error occurrence.
  * @retval None
  */
void Error_Handler(void)
{
  /* USER CODE BEGIN Error_Handler_Debug */
  /* User can add his own implementation to report the HAL error return state */
  __disable_irq();
  while (1)
  {
  }
  /* USER CODE END Error_Handler_Debug */
}

#ifdef  USE_FULL_ASSERT
/**
  * @brief  Reports the name of the source file and the source line number
  *         where the assert_param error has occurred.
  * @param  file: pointer to the source file name
  * @param  line: assert_param error line source number
  * @retval None
  */
void assert_failed(uint8_t *file, uint32_t line)
{
  /* USER CODE BEGIN 6 */
  /* User can add his own implementation to report the file name and line number,
     ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */
  /* USER CODE END 6 */
}
#endif /* USE_FULL_ASSERT */

4.5、gpio.c

/* USER CODE BEGIN Header */
/**
  ******************************************************************************
  * @file    gpio.c
  * @brief   This file provides code for the configuration
  *          of all used GPIO pins.
  ******************************************************************************
  * @attention
  *
  * Copyright (c) 2023 STMicroelectronics.
  * All rights reserved.
  *
  * This software is licensed under terms that can be found in the LICENSE file
  * in the root directory of this software component.
  * If no LICENSE file comes with this software, it is provided AS-IS.
  *
  ******************************************************************************
  */
/* USER CODE END Header */

/* Includes ------------------------------------------------------------------*/
#include "gpio.h"

/* USER CODE BEGIN 0 */

/* USER CODE END 0 */

/*----------------------------------------------------------------------------*/
/* Configure GPIO                                                             */
/*----------------------------------------------------------------------------*/
/* USER CODE BEGIN 1 */

/* USER CODE END 1 */

/** Configure pins as
        * Analog
        * Input
        * Output
        * EVENT_OUT
        * EXTI
*/
void MX_GPIO_Init(void)
{

  GPIO_InitTypeDef GPIO_InitStruct = {0};

  /* GPIO Ports Clock Enable */
  __HAL_RCC_GPIOD_CLK_ENABLE();
  __HAL_RCC_GPIOA_CLK_ENABLE();
  __HAL_RCC_GPIOB_CLK_ENABLE();

  /*Configure GPIO pin Output Level */
  HAL_GPIO_WritePin(GPIOB, GPIO_PIN_6, GPIO_PIN_RESET);

  /*Configure GPIO pin Output Level */
  HAL_GPIO_WritePin(GPIOB, GPIO_PIN_8, GPIO_PIN_SET);

  /*Configure GPIO pins : PB6 PB8 */
  GPIO_InitStruct.Pin = GPIO_PIN_6|GPIO_PIN_8;
  GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);

  /*Configure GPIO pin : PB7 */
  GPIO_InitStruct.Pin = GPIO_PIN_7;
  GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);

}

/* USER CODE BEGIN 2 */

/* USER CODE END 2 */

4.6、tim.c

/* USER CODE BEGIN Header */
/**
  ******************************************************************************
  * @file    tim.c
  * @brief   This file provides code for the configuration
  *          of the TIM instances.
  ******************************************************************************
  * @attention
  *
  * Copyright (c) 2023 STMicroelectronics.
  * All rights reserved.
  *
  * This software is licensed under terms that can be found in the LICENSE file
  * in the root directory of this software component.
  * If no LICENSE file comes with this software, it is provided AS-IS.
  *
  ******************************************************************************
  */
/* USER CODE END Header */
/* Includes ------------------------------------------------------------------*/
#include "tim.h"

/* USER CODE BEGIN 0 */

/* USER CODE END 0 */

TIM_HandleTypeDef htim2;

/* TIM2 init function */
void MX_TIM2_Init(void)
{

  /* USER CODE BEGIN TIM2_Init 0 */

  /* USER CODE END TIM2_Init 0 */

  TIM_ClockConfigTypeDef sClockSourceConfig = {0};
  TIM_MasterConfigTypeDef sMasterConfig = {0};

  /* USER CODE BEGIN TIM2_Init 1 */

  /* USER CODE END TIM2_Init 1 */
  htim2.Instance = TIM2;
  htim2.Init.Prescaler = 71;
  htim2.Init.CounterMode = TIM_COUNTERMODE_UP;
  htim2.Init.Period = 65535;
  htim2.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
  htim2.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_ENABLE;
  if (HAL_TIM_Base_Init(&htim2) != HAL_OK)
  {
    Error_Handler();
  }
  sClockSourceConfig.ClockSource = TIM_CLOCKSOURCE_INTERNAL;
  if (HAL_TIM_ConfigClockSource(&htim2, &sClockSourceConfig) != HAL_OK)
  {
    Error_Handler();
  }
  sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;
  sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
  if (HAL_TIMEx_MasterConfigSynchronization(&htim2, &sMasterConfig) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN TIM2_Init 2 */

  /* USER CODE END TIM2_Init 2 */

}

void HAL_TIM_Base_MspInit(TIM_HandleTypeDef* tim_baseHandle)
{

  if(tim_baseHandle->Instance==TIM2)
  {
  /* USER CODE BEGIN TIM2_MspInit 0 */

  /* USER CODE END TIM2_MspInit 0 */
    /* TIM2 clock enable */
    __HAL_RCC_TIM2_CLK_ENABLE();
  /* USER CODE BEGIN TIM2_MspInit 1 */

  /* USER CODE END TIM2_MspInit 1 */
  }
}

void HAL_TIM_Base_MspDeInit(TIM_HandleTypeDef* tim_baseHandle)
{

  if(tim_baseHandle->Instance==TIM2)
  {
  /* USER CODE BEGIN TIM2_MspDeInit 0 */

  /* USER CODE END TIM2_MspDeInit 0 */
    /* Peripheral clock disable */
    __HAL_RCC_TIM2_CLK_DISABLE();
  /* USER CODE BEGIN TIM2_MspDeInit 1 */

  /* USER CODE END TIM2_MspDeInit 1 */
  }
}

/* USER CODE BEGIN 1 */

/* USER CODE END 1 */

4.7、stm32f1xx_it.c

/* USER CODE BEGIN Header */
/**
  ******************************************************************************
  * @file    stm32f1xx_it.c
  * @brief   Interrupt Service Routines.
  ******************************************************************************
  * @attention
  *
  * Copyright (c) 2023 STMicroelectronics.
  * All rights reserved.
  *
  * This software is licensed under terms that can be found in the LICENSE file
  * in the root directory of this software component.
  * If no LICENSE file comes with this software, it is provided AS-IS.
  *
  ******************************************************************************
  */
/* USER CODE END Header */

/* Includes ------------------------------------------------------------------*/
#include "main.h"
#include "stm32f1xx_it.h"
/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */
/* USER CODE END Includes */

/* Private typedef -----------------------------------------------------------*/
/* USER CODE BEGIN TD */

/* USER CODE END TD */

/* Private define ------------------------------------------------------------*/
/* USER CODE BEGIN PD */

/* USER CODE END PD */

/* Private macro -------------------------------------------------------------*/
/* USER CODE BEGIN PM */

/* USER CODE END PM */

/* Private variables ---------------------------------------------------------*/
/* USER CODE BEGIN PV */

/* USER CODE END PV */

/* Private function prototypes -----------------------------------------------*/
/* USER CODE BEGIN PFP */

/* USER CODE END PFP */

/* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */

/* USER CODE END 0 */

/* External variables --------------------------------------------------------*/

/* USER CODE BEGIN EV */

/* USER CODE END EV */

/******************************************************************************/
/*           Cortex-M3 Processor Interruption and Exception Handlers          */
/******************************************************************************/
/**
  * @brief This function handles Non maskable interrupt.
  */
void NMI_Handler(void)
{
  /* USER CODE BEGIN NonMaskableInt_IRQn 0 */

  /* USER CODE END NonMaskableInt_IRQn 0 */
  /* USER CODE BEGIN NonMaskableInt_IRQn 1 */
  while (1)
  {
  }
  /* USER CODE END NonMaskableInt_IRQn 1 */
}

/**
  * @brief This function handles Hard fault interrupt.
  */
void HardFault_Handler(void)
{
  /* USER CODE BEGIN HardFault_IRQn 0 */

  /* USER CODE END HardFault_IRQn 0 */
  while (1)
  {
    /* USER CODE BEGIN W1_HardFault_IRQn 0 */
    /* USER CODE END W1_HardFault_IRQn 0 */
  }
}

/**
  * @brief This function handles Memory management fault.
  */
void MemManage_Handler(void)
{
  /* USER CODE BEGIN MemoryManagement_IRQn 0 */

  /* USER CODE END MemoryManagement_IRQn 0 */
  while (1)
  {
    /* USER CODE BEGIN W1_MemoryManagement_IRQn 0 */
    /* USER CODE END W1_MemoryManagement_IRQn 0 */
  }
}

/**
  * @brief This function handles Prefetch fault, memory access fault.
  */
void BusFault_Handler(void)
{
  /* USER CODE BEGIN BusFault_IRQn 0 */

  /* USER CODE END BusFault_IRQn 0 */
  while (1)
  {
    /* USER CODE BEGIN W1_BusFault_IRQn 0 */
    /* USER CODE END W1_BusFault_IRQn 0 */
  }
}

/**
  * @brief This function handles Undefined instruction or illegal state.
  */
void UsageFault_Handler(void)
{
  /* USER CODE BEGIN UsageFault_IRQn 0 */

  /* USER CODE END UsageFault_IRQn 0 */
  while (1)
  {
    /* USER CODE BEGIN W1_UsageFault_IRQn 0 */
    /* USER CODE END W1_UsageFault_IRQn 0 */
  }
}

/**
  * @brief This function handles System service call via SWI instruction.
  */
void SVC_Handler(void)
{
  /* USER CODE BEGIN SVCall_IRQn 0 */

  /* USER CODE END SVCall_IRQn 0 */
  /* USER CODE BEGIN SVCall_IRQn 1 */

  /* USER CODE END SVCall_IRQn 1 */
}

/**
  * @brief This function handles Debug monitor.
  */
void DebugMon_Handler(void)
{
  /* USER CODE BEGIN DebugMonitor_IRQn 0 */

  /* USER CODE END DebugMonitor_IRQn 0 */
  /* USER CODE BEGIN DebugMonitor_IRQn 1 */

  /* USER CODE END DebugMonitor_IRQn 1 */
}

/**
  * @brief This function handles Pendable request for system service.
  */
void PendSV_Handler(void)
{
  /* USER CODE BEGIN PendSV_IRQn 0 */

  /* USER CODE END PendSV_IRQn 0 */
  /* USER CODE BEGIN PendSV_IRQn 1 */

  /* USER CODE END PendSV_IRQn 1 */
}

/**
  * @brief This function handles System tick timer.
  */
void SysTick_Handler(void)
{
  /* USER CODE BEGIN SysTick_IRQn 0 */

  /* USER CODE END SysTick_IRQn 0 */
  HAL_IncTick();
  /* USER CODE BEGIN SysTick_IRQn 1 */

  /* USER CODE END SysTick_IRQn 1 */
}

/******************************************************************************/
/* STM32F1xx Peripheral Interrupt Handlers                                    */
/* Add here the Interrupt Handlers for the used peripherals.                  */
/* For the available peripheral interrupt handler names,                      */
/* please refer to the startup file (startup_stm32f1xx.s).                    */
/******************************************************************************/

/* USER CODE BEGIN 1 */

/* USER CODE END 1 */

4.8、超声波测距效果

1.代码编译,烧录之后
嵌入式-stm32-SR04超声波测距介绍及实战_第9张图片2.测试超声波测距
把手放在距离sr04 5cm以内,led灯会亮,再远灯会灭
嵌入式-stm32-SR04超声波测距介绍及实战_第10张图片

嵌入式-stm32-SR04超声波测距介绍及实战_第11张图片

以上,完

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