如何用WiFi实现无线定位

      ② 使用“ESP8266调试工具”将与主控板连接的WiFi模块设置为Statino模式，按照下面方法连接ESP8266模块和BigFish主控板，OLED显示屏使用四芯输入排线与BigFish进行连接。

③ 将实验例程（ESP8266RSSIPosition.ino）下载到主控板中。

/*------------------------------------------------------------------------------------
  版权说明：Copyright 2023 Robottime(Beijing) Technology Co., Ltd. All Rights Reserved.
           Distributed under MIT license.See file LICENSE for detail or copy at
           https://opensource.org/licenses/MIT
           by 机器谱 2023-09-12 https://www.robotway.com/
  ------------------------------*/
 
/*将与主控板相连接的wifi模块使用“esp8266调试工具软件”设置为Station模式
  将其余三个模块设置为AP模式，并记录其NAME,存储在程序中*/
 
//#define DEBUG
 
#define ESP_AP_NUMBER 3
 
#include 
 
#include 
 
#include 
 
#include 
 
SoftwareSerial myESP(2,3);
 
RssiPositionComputer myPositionComputer;
 
Point2D master_point;
 
LCD_SSD1306 lcd;
 
char esp_ap_name[ESP_AP_NUMBER][10] = {"ESP826601","ESP826602","ESP826603"};
 
int   rssi[ESP_AP_NUMBER];
 
float distance[ESP_AP_NUMBER];
 
void setup()
 
{
 
delay(1000);
 
Serial.begin(115200);
 
myESP.begin(9600);
 
#ifdef DEBUG
 
Serial.println("begin");
 
#endif
 
while(myESP.available()&&myESP.read());
 
while(!myESP.available())
 
{
 
myESP.println("AT");
 
delay(1000);
 
}
 
while(myESP.available()&&myESP.read());
 
#ifdef DEBUG
 
Serial.println("Resonse ok");
 
#endif
 
lcd.begin();
 
    lcd.clear();
 
    lcd.setCursor(30,4);
 
    lcd.print("Hello, world!");
 
}
 
void loop()
 
{
 
int n = searchESPAP(esp_ap_name,rssi);
 
for(int i=0;i
 
{
 
distance[i] = rssiToDistance(rssi[i]);
 
Serial.print(distance[i]);
 
Serial.print('\t');
 
}
 
Serial.print(n);
 
Serial.print('\t');
 
if(myPositionComputer.distanceToPoint(distance[0],distance[1],distance[2],&master_point)==true)
 
    {
 
      Serial.print(master_point.x);
 
      Serial.print('\t');
 
      Serial.print(master_point.y);
 
      Serial.print('\t');
 
      Serial.println("position okok");
 
      lcd.clear();
 
      lcd.setCursor(30,2);
 
      lcd.printLong(master_point.x*100,FONT_SIZE_LARGE);   //按厘米输出
 
      lcd.setCursor(30,5);
 
      lcd.printLong(master_point.y*100,FONT_SIZE_LARGE);
 
    }
 
    else
 
    {
 
    lcd.clear();
 
    lcd.setCursor(30,4);
 
    lcd.print("position ERROR!");
 
        Serial.println("position ERROR");   
 
    }
 
}
 
int nameToNumber(char in[],char name[][10])
 
{
 
for(int i=0;i<3;i++)
 
{
 
for(int j=0;j<9;j++)
 
{
 
if(in[j] != name[i][j])
 
break;
 
if(j==8)
 
return(i);
 
}
 
}
 
return(-1);
 
}
 
byte searchESPAP(char name[][10], int rs[])
 
{
 
byte search_result_number = 0;
 
int state = 0;
 
int n;
 
int ap_n;
 
char name_string[10];
 
char rssi_string[4];
 
while(myESP.available()&&myESP.read());
 
myESP.println("AT+CWLAP");
 
delay(100);
 
while(myESP.available()&&myESP.read());
 
unsigned long t = millis();
 
while(!myESP.available())
 
{
 
if(millis()-t<3000)
 
delay(5);
 
else
 
return(0);
 
}
 
#ifdef DEBUG
 
Serial.println("received........");
 
#endif
 
t = millis();
 
while(myESP.available()||(millis()-t<3000))
 
{
 
if(!myESP.available())
 
continue;
 
char in_char = myESP.read();
 
#ifdef DEBUG
 
Serial.print(in_char);
 
#endif
 
if( (state == 0)&&(in_char=='(') )
 
{
 
state = 1;
 
n = -4;
 
}
 
else if(state == 1)
 
{
 
n++;
 
if(n>=0)
 
name_string[n] = in_char;
 
if(n == 8)
 
{
 
n = -3;
 
ap_n = nameToNumber(name_string,name);
 
if(ap_n != -1)
 
{
 
state = 2;
 
#ifdef DEBUG
 
Serial.print('\n');
 
Serial.print("ap_n:");Serial.println(ap_n);
 
#endif
 
}
 
else
 
{
 
state = 0;
 
}
 
}
 
}
 
else if(state==2)
 
{
 
n++;
 
if(n>=0)
 
rssi_string[n] = in_char;
 
if(n == 2)
 
{
 
rs[ap_n] = atof(rssi_string);
 
state = 0;
 
search_result_number++;
 
#ifdef DEBUG
 
Serial.print('\n');
 
Serial.print("rssi["+String(ap_n)+"]:");Serial.println(rs[ap_n]);
 
#endif
 
}
 
}
 
}
 
return(search_result_number);
 
}
 
float rssiToDistance(int rssi)
 
{
 
float dis = 0;
 
dis = pow(10.0,((abs(rssi)-47)/10.0/2.212));
 
return dis;
 
}

④ 将不同模块按照三点定位摆放开（在1m×1m的空间内），如下图所示，观察实验效果。

程序源代码、ESP8266调试工具、ESP8266相关学习资料详见 如何用WiFi实现无线定位