Using ultrasonic ranging module

Ultrasonic ranging module:

Ultrasonic Ranging module performs a variety of types, now more commonly used URM37 ultrasonic sensor 232 is by default an interface, the interface can be adjusted to TTL, URM05 high-power ultrasonic transducer can be 10 meters from the test, the test is considered to be the more distant a the models, in addition to the more common abroad several SRF series of ultrasonic module, the module current ultrasonic energy to the accuracy of 1cm

working principle:

Ultrasonic Ranging module is used to measure the distance of a product, and on receiving an ultrasonic wave transmitted by using the time difference and the speed of sound, the module calculates the distance to the front obstacle.

And the specific use of the code

1. Definitions pin

#include<reg52.h>
#include<stdio.h>
sbit Trig = P1^0;
sbit Echo = P1^1;

2, setting the baud rate

void init_115200()
{
	SCON = 0x50;
	T2CON |= 0X30;
	TH1 = 0xFF;
	TL1 = 0xFD;
	RCAP2H = 0XFF;
	RCAP2L = 0XFD;
	TR2 = 1;
	ES = 1;
	EA = 1;
	ET0=1;
}

3, the transmission time set

void Delay10us()
{
	TMOD |= 0x1;
	TH0 = 0xFF;
	TL0 = 0xF6;
	TR0 = 1;
	while(!TF0);
	TF0 = 0;
}

 void CSB_Rstart () // start ultrasonic module initialization
{
	Trig=0;
	Trig=1;
	Delay10us();
	Trig=0;
}

4, acquisition time and distance

int gettime () // get time
{
	unsigned int time = 0;
	time = TH0<<8 | TL0;  //TH0*256+TL0
	return time;
}

 float CSB_Getdis (unsigned int time) // get the distance 
{
	float distance;
	distance = (float)time * 0.0017;
	TH0=0;
	 TL0 = 0; // clear the timer ·
	return distance;
}

void star()
{
	TH0 = 0;
	TL0 = 0;
	TR0 = 1;
}

void end()
{
	TR0 = 0;
}

   void CSB_GetOnce () // Get a distance of ultrasonic ranging module
{
	CSB_Rstart();
	 while (Echo!); // wait zero when Echo
	star();
	 while (Echo); // if the count is 1 and Echo wait
	end();
}

5, the measured distance printed

int main()
{
	unsigned int time = 0;
	float dis;
	char buf[24]={'\0'};
	init_115200();
	
	while(1)
	{  
		CSB_GetOnce();
		time = gettime();
		dis = CSB_Getdis(time);
		sprintf(buf,"dis=%fcm\r\n",dis);
		delay();
		upt(buf);
	}
	return 0;
}

Print function

void shuchu(char c)
 {
	SBUF = c;
	while(TI==0);
	TI = 0;	   
}

void upt(char *p)
 {
 	while(*p != '\0'){
	shuchu(*p);
	p++;
	}
 }

Delay function

void delay()
{
	int i;
	int j;
	for(i=0;i<100;i++)
		for(j = 0;j<2000;j++);
}