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【STM32】超声波传感器HC-SR04知识_hc-sr04超声波传感器

作者：小蓝xlanll | 2024-04-08 03:39:00

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hc-sr04超声波传感器

一、超声波HC_SR04简介

        超声波传感器模块上面通常有两个超声波元器件，一个用于发射，一个用于接收。

        电路板上有四个引脚：VCC、GND、Trig（触发）、Echo（回应）。

        工作电压与电流：5V，15mA

        感应距离：2~400cm

        感测角度：不小于15度

        被测物体的面积不要小于50平方厘米并且尽量平整

        具备温度补偿电路

二、超声波原理

        距离公式：

        高电平持续时间*声速(340m/s)/2

三、超声波测距步骤

  1. 配置GPIO引脚结构体(Trig,Echo)
  2. 配置定时器4结构体
  3. 配置定时器4中断结构体
  4. 开启时钟（定时器、GPIO）
  5. Trig引脚输出高电平(10us以上)，然后关闭
  6. 等待Echo引脚输出高电平开始，定时器打开->开启计数器计数
  7. 等待Echo引脚输出高电平结束，定时器关闭->停止计数器计数

四、硬件接线

  1. GND——GND
  2. VCC——5V
  3. Trig——PB11
  4. Echo——PB10

五、模块化程序

  1. #ifndef __SYS_H
  2. #define __SYS_H	
  3. #include "stm32f10x.h"
  4.  
  5.  
  6. #define SYSTEM_SUPPORT_UCOS		0		
  7.  
  8. #define BITBAND(addr, bitnum) ((addr & 0xF0000000)+0x2000000+((addr &0xFFFFF)<<5)+(bitnum<<2)) 
  9. #define MEM_ADDR(addr)  *((volatile unsigned long  *)(addr)) 
  10. #define BIT_ADDR(addr, bitnum)   MEM_ADDR(BITBAND(addr, bitnum)) 
  11.  
  12. #define GPIOA_ODR_Addr    (GPIOA_BASE+12) //0x4001080C 
  13. #define GPIOB_ODR_Addr    (GPIOB_BASE+12) //0x40010C0C 
  14. #define GPIOC_ODR_Addr    (GPIOC_BASE+12) //0x4001100C 
  15. #define GPIOD_ODR_Addr    (GPIOD_BASE+12) //0x4001140C 
  16. #define GPIOE_ODR_Addr    (GPIOE_BASE+12) //0x4001180C 
  17. #define GPIOF_ODR_Addr    (GPIOF_BASE+12) //0x40011A0C    
  18. #define GPIOG_ODR_Addr    (GPIOG_BASE+12) //0x40011E0C    
  19.  
  20. #define GPIOA_IDR_Addr    (GPIOA_BASE+8) //0x40010808 
  21. #define GPIOB_IDR_Addr    (GPIOB_BASE+8) //0x40010C08 
  22. #define GPIOC_IDR_Addr    (GPIOC_BASE+8) //0x40011008 
  23. #define GPIOD_IDR_Addr    (GPIOD_BASE+8) //0x40011408 
  24. #define GPIOE_IDR_Addr    (GPIOE_BASE+8) //0x40011808 
  25. #define GPIOF_IDR_Addr    (GPIOF_BASE+8) //0x40011A08 
  26. #define GPIOG_IDR_Addr    (GPIOG_BASE+8) //0x40011E08 
  27.  
  28.  
  29. #define PAout(n)   BIT_ADDR(GPIOA_ODR_Addr,n)  //Êä³ö 
  30. #define PAin(n)    BIT_ADDR(GPIOA_IDR_Addr,n)  //ÊäÈë 
  31.  
  32. #define PBout(n)   BIT_ADDR(GPIOB_ODR_Addr,n)  //Êä³ö 
  33. #define PBin(n)    BIT_ADDR(GPIOB_IDR_Addr,n)  //ÊäÈë 
  34.  
  35. #define PCout(n)   BIT_ADDR(GPIOC_ODR_Addr,n)  //Êä³ö 
  36. #define PCin(n)    BIT_ADDR(GPIOC_IDR_Addr,n)  //ÊäÈë 
  37.  
  38. #define PDout(n)   BIT_ADDR(GPIOD_ODR_Addr,n)  //Êä³ö 
  39. #define PDin(n)    BIT_ADDR(GPIOD_IDR_Addr,n)  //ÊäÈë 
  40.  
  41. #define PEout(n)   BIT_ADDR(GPIOE_ODR_Addr,n)  //Êä³ö 
  42. #define PEin(n)    BIT_ADDR(GPIOE_IDR_Addr,n)  //ÊäÈë
  43.  
  44. #define PFout(n)   BIT_ADDR(GPIOF_ODR_Addr,n)  //Êä³ö 
  45. #define PFin(n)    BIT_ADDR(GPIOF_IDR_Addr,n)  //ÊäÈë
  46.  
  47. #define PGout(n)   BIT_ADDR(GPIOG_ODR_Addr,n)  //Êä³ö 
  48. #define PGin(n)    BIT_ADDR(GPIOG_IDR_Addr,n)  //ÊäÈë
  49.  
  50.  
  51.  
  52. void NVIC_Configuration(void);
  53.  
  54.  
  55.  
  56. #endif
  1. #include "sys.h"
  2. #include "stm32f10x.h" 
  3.  
  4. void NVIC_Configuration(void)
  5. {
  6.  
  7.     NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);	
  8.  
  9. }
  1. #include "hc.h"
  2. #include "Delay.h"
  3.  
  4. #define HCSR04_PORT     GPIOB
  5. #define HCSR04_CLK      RCC_APB2Periph_GPIOB
  6. #define HCSR04_TRIG     GPIO_Pin_11
  7. #define HCSR04_ECHO     GPIO_Pin_10
  8.  
  9. u16 msHcCount = 0; 
  10.  
  11. void HC_Init(void)
  12. {  
  13.     TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;   
  14.     GPIO_InitTypeDef GPIO_InitStructure;
  15.     RCC_APB2PeriphClockCmd(HCSR04_CLK, ENABLE);
  16.  
  17.     GPIO_InitStructure.GPIO_Pin =HCSR04_TRIG;      
  18.     GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  19.     GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
  20.     GPIO_Init(HCSR04_PORT, &GPIO_InitStructure);
  21.     GPIO_ResetBits(HCSR04_PORT,HCSR04_TRIG);
  22.  
  23.     GPIO_InitStructure.GPIO_Pin = HCSR04_ECHO;     
  24.     GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
  25.     GPIO_Init(HCSR04_PORT, &GPIO_InitStructure);  
  26.     GPIO_ResetBits(HCSR04_PORT,HCSR04_ECHO);    
  27.  
  28.  
  29.     RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4, ENABLE);   
  30.  
  31.     TIM_DeInit(TIM2);
  32.     TIM_TimeBaseStructure.TIM_Period = (1000-1); 
  33.     TIM_TimeBaseStructure.TIM_Prescaler =(72-1); 
  34.     TIM_TimeBaseStructure.TIM_ClockDivision=TIM_CKD_DIV1;
  35.     TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;  
  36.     TIM_TimeBaseInit(TIM4, &TIM_TimeBaseStructure);          
  37.  
  38.     TIM_ClearFlag(TIM4, TIM_FLAG_Update);  
  39.     TIM_ITConfig(TIM4,TIM_IT_Update,ENABLE);    
  40.  
  41.     NVIC_InitTypeDef NVIC_InitStructure;
  42.     NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);
  43.  
  44.     NVIC_InitStructure.NVIC_IRQChannel = TIM4_IRQn;             
  45.     NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;  
  46.     NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;         
  47.     NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;       
  48.     NVIC_Init(&NVIC_InitStructure);
  49.  
  50.     TIM_Cmd(TIM4,DISABLE);     
  51. }
  52.  
  53.  
  54.  
  55. static void OpenTimerForHc()  
  56. {
  57.     TIM_SetCounter(TIM4,0);
  58.     msHcCount = 0;
  59.     TIM_Cmd(TIM4, ENABLE); 
  60. }
  61.  
  62.  
  63. static void CloseTimerForHc()    
  64. {
  65.     TIM_Cmd(TIM4, DISABLE); 
  66. }
  67.  
  68.  
  69. void TIM4_IRQHandler(void)  
  70. {
  71.     if (TIM_GetITStatus(TIM4, TIM_IT_Update) != RESET)  
  72.    {
  73.        TIM_ClearITPendingBit(TIM4, TIM_IT_Update  ); 
  74.        msHcCount++;
  75.    }
  76. }
  77.  
  78.  
  79.  
  80.   u32 GetEchoTimer(void)
  81. {
  82.     u32 t = 0;
  83.     t = msHcCount*1000;
  84.     t += TIM_GetCounter(TIM4);
  85.     TIM4->CNT = 0;  
  86.     Delay_ms(50);
  87.     return t;
  88. }
  89.  
  90.   float HC_Get(void )
  91. {
  92.     int t = 0;
  93.     int i = 0;
  94.     float lengthTemp = 0;
  95.     float sum = 0;
  96.     while(i!=5)
  97.    {
  98.        TRIG_Send = 1;      
  99.        Delay_us(20);
  100.        TRIG_Send = 0;
  101.        while(ECHO_Reci == 0);      
  102.        OpenTimerForHc();        
  103.        i = i + 1;
  104.        while(ECHO_Reci == 1);
  105.        CloseTimerForHc();        
  106.        t = GetEchoTimer();        
  107.        lengthTemp = ((float)t/58.0);//cm
  108.        sum = lengthTemp + sum ;
  109.  
  110.    }
  111.     lengthTemp = sum/5.0;
  112.     return lengthTemp;
  113. }
  1. #ifndef __HC_H
  2. #define __HC_H	
  3. #include "sys.h"
  4.  
  5. void HC_Init(void);
  6. static void OpenTimerForHc(void);
  7. static void CloseTimerForHc(void);
  8. void TIM4_IRQHandler(void);
  9. u32 GetEchoTimer(void);
  10. float HC_Get(void );
  11.  
  12. #define TRIG_Send  PBout(11)
  13. #define ECHO_Reci  PBin(10)
  14. #endif
  1. #include "stm32f10x.h"                  // Device header
  2. #include "Delay.h"
  3. #include "OLED.h"
  4. #include "HC.h"
  5.  
  6. uint32_t Length;
  7. float length;
  8.  
  9.  
  10. int main(void)
  11. {
  12. 	
  13.   OLED_Init();
  14.   OLED_ShowString(1,1,"Length:");
  15.   OLED_ShowString(2,10,"cm");
  16.   HC_Init();
  17.  
  18. while(1)
  19. 	{
  20. 		length =HC_Get(); 
  21. 		Length = length*100; //eg:54.25->5425
  22. 		OLED_ShowNum(2,4,Length/1000,1);  // 千
  23. 		OLED_ShowNum(2,5,Length%1000/100,1); //百
  24. 		OLED_ShowString(2,6,".");
  25. 		OLED_ShowNum(2,7,Length%100/10,1); //十
  26. 		OLED_ShowNum(2,8,Length%10/1,1);  //个
  27. 		
  28.   }
  29. }

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