我有一個圖片18F4550如何從超聲波傳感器讀取距離

Question

我有PIC 18f4550，需要在picBasic pro中編寫代碼。
我正在連接直流電動機，超聲波傳感器和紅外傳感器等
我已經做了所有事情，但仍然對如何連接超聲波傳感器感到困惑。

這是PIC中的超聲波針

trisb.3=0    'trigger ultrasound
trisb.4=1    ' Echo from Ultrasound

我需要一個示例代碼

Answer 1

對其進行編程的基本步驟：

1-為TRIGGER提供超聲波模塊
2-聽回音
收到ECHO HIGH時的3啟動定時器
當ECHO變為低電平時的4停止定時器
5讀取定時器值
6-將其轉換為距離
7-顯示它

距離計算

• 距離=速度*時間
  
• 令d為超聲波傳感器與目標之間的距離
  
• 超聲波脈沖傳播的總距離：2d（向前和向后）
  
• 空氣聲速：340 m / s = 34000 cm / s
  
• 因此，d =（34000 *時間）/ 2，其中時間=（TMR1H：TMR1L）/（1000000）
  
• 因此，d =（TMR1H：TMR1L）/58.82 cm
  
• TMR1H：TMR1L = TMR1L | （TMR1H << 8）
  

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MikroC代碼

// LCD module connections
sbit LCD_RS at RD2_bit;
sbit LCD_EN at RD3_bit;
sbit LCD_D4 at RD4_bit;
sbit LCD_D5 at RD5_bit;
sbit LCD_D6 at RD6_bit;
sbit LCD_D7 at RD7_bit;

sbit LCD_RS_Direction at TRISD2_bit;
sbit LCD_EN_Direction at TRISD3_bit;
sbit LCD_D4_Direction at TRISD4_bit;
sbit LCD_D5_Direction at TRISD5_bit;
sbit LCD_D6_Direction at TRISD6_bit;
sbit LCD_D7_Direction at TRISD7_bit;
// End LCD module connections

void main()
{
  int a;
  char txt[7];
  Lcd_Init();
  Lcd_Cmd(_LCD_CLEAR);          // Clear display
  Lcd_Cmd(_LCD_CURSOR_OFF);     // Cursor off

  TRISB = 0b00010000;           //RB4 as Input PIN (ECHO)

  Lcd_Out(1,1,"Developed By");
  Lcd_Out(2,1,"Mina Karam");

  Delay_ms(3000);
  Lcd_Cmd(_LCD_CLEAR);

  T1CON = 0x10;                 //Initialize Timer Module

  while(1)
  {
    TMR1H = 0;                  //Sets the Initial Value of Timer
    TMR1L = 0;                  //Sets the Initial Value of Timer

    PORTB.F0 = 1;               //TRIGGER HIGH
    Delay_us(10);               //10uS Delay
    PORTB.F0 = 0;               //TRIGGER LOW

    while(!PORTB.F4);           //Waiting for Echo
    T1CON.F0 = 1;               //Timer Starts
    while(PORTB.F4);            //Waiting for Echo goes LOW
    T1CON.F0 = 0;               //Timer Stops

    a = (TMR1L | (TMR1H<<8));   //Reads Timer Value
    a = a/58.82;                //Converts Time to Distance
    a = a + 1;                  //Distance Calibration
    if(a>=2 && a<=400)          //Check whether the result is valid or not
    {
      IntToStr(a,txt);
      Ltrim(txt);
      Lcd_Cmd(_LCD_CLEAR);
      Lcd_Out(1,1,"Distance = ");
      Lcd_Out(1,12,txt);
      Lcd_Out(1,15,"cm");
    }
    else
    {
      Lcd_Cmd(_LCD_CLEAR);
      Lcd_Out(1,1,"Out of Range");
    }
    Delay_ms(400);
  }
}