使用超声波传感器时，距离等于什么度量单位？

Question

我目前正在使用超声波接近传感器来测量水箱中的水被充满了多少。我首先尝试接收传感器和反射波的对象之间的距离测量。我已经尝试构建自己的代码（使用C语言），但是我不确定我的问题在哪里。我已编写代码以在LCD上显示。我得到的数字是669，A45，h45。下面是我为执行此任务而编写的注释函数。

void distance_sensor(void)
{
    DDRC= 0x0F;    //enables only one nybble to be an output

    double timecnt;
    double distance;
    int echo;

    char distb [16] = {"Container up to:"};
    lcd_write(distb, 16, line_1);  //displays banner on LCD

    echo = (PINC & 0x10);  //declares the input echo from the 2nd nybble

    distance= 0;           //initialization
    timecnt = 0;

    PORTC = 0x00;
    _delay_ms(1.0);

    PORTC = 0x0F;
    _delay_ms(5.2);        //creating a 10 us output square wave and sending it out through port c
    PORTC = 0x00;

    while(echo==0) 
    {
        echo = (PINC & 0x10);   //rechecking the input
        timecnt = timecnt + 1;  //time taken for the wave to reflect back to the sensor             
        _delay_us(100.0);
    }

    timecnt= timecnt*100;
    distance = (timecnt*0.000343)/2;  
    hextodec(distance);         //function made to split the value into msd, nsd, lsd and displays on LCD

    return; 
}

Answer 1

一旦[[TRIG]]输入上出现高电平，超声模块就会在ECHO

输出上将其设置为低电平，并发出一阵声音脉冲。如果有障碍物，声音突发会作为回声反射回去。一旦模块检测到回声，就会在ECHO