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abhilash_patel
Published © GPL3+

Ultrasound Sensor: 2D Tracking With Arduino

Typically ultrasound sensor used to measure the range of the target, this project can locate the target in two dimensions.

BeginnerFull instructions provided11,005
Ultrasound Sensor: 2D Tracking With Arduino

Things used in this project

Hardware components

Arduino UNO
Arduino UNO
×1
Ultrasonic Sensor - HC-SR04 (Generic)
Ultrasonic Sensor - HC-SR04 (Generic)
×4

Software apps and online services

Arduino IDE
Arduino IDE

Story

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Code

Multi sensor 2D tracking

Arduino
// below code is for target tracking in 2D using 2 ot more ultrasound sensor
//more details: https://youtu.be/MFVwW3jtXvw
//by abhilash

int n=4;  //nos of sensor
int Tx[4]={12,8,6,4};       //pin number: sensor 1, sensor 2,...
int Rx[4]={11,7,5,3};       //pin number: sensor 1, sensor 2,...
float Raw[4];
float Position[4]={0,41,85,130}; //all sensor midpoint are located in one line only, 
                                 // position mentoined from mid point for left most sensor
float Calc_X[6];        //for 4 sensor, total calculated outpurt wil be 4C2=6 combinations
float Calc_Y[6];
int test[6];

float Final_X, Final_Y; // final calculated values wil be stored in these variables

void setup() 
{
      Serial.begin(250000); // Starting Serial Terminal

        for(int i=0;i<n;i++)
        {
         pinMode(Tx[i], OUTPUT);   
         pinMode(Rx[i], INPUT);
        }
}

void loop() 
{

Raw_cap();
Position_calc();
Fuse_data();
Serial.print(Final_X);  // X coordinate
Serial.print("\t");
Serial.println(Final_Y);

}






//==============================Functions==============================//



//Raw_cap is function to capture data from various sensor
//by setting value of samples, average of defined samples can be taken as output
void Raw_cap()          
{ 
  float sample=1;
  for(int i=0; i<n; i++)
        { 
          Raw[i]=0;
            for(int j=0; j<sample; j++)
             {              
                digitalWrite(Tx[i], LOW);   
                pinMode(Rx[i], INPUT);
                digitalWrite(Tx[i], LOW);
                delayMicroseconds(2);
                digitalWrite(Tx[i], HIGH);
                delayMicroseconds(10);
                digitalWrite(Tx[i], LOW);
                Raw[i] =Raw[i] +  pulseIn(Rx[i], HIGH,5000);
                delay(15);
             }
          Raw[i]=Raw[i]/sample;
          Raw[i]=Raw[i]*343/2000;
    //      Serial.println(Raw[i]);
          
        }
}


//-------------------------------------------------------------------------------------//
// this function applies tringle properties to find co-ordinates of 
// various combination of ultrasound sensor
void Position_calc()
{float d1,d2,a;
int  count,test_temp;
count=0;
  for(int i=0;i<n;i++)
  {
    for(int j=i+1;j<n;j++)
    {
    d1=Raw[i]; d2=Raw[j]; a=Position[j]- Position[i];
    test_temp=check(d1,d2,a);
   
      if(test_temp==0)
        {      
            Calc_X[count]=0;
            Calc_Y[count]=0;
            test[count]=0;        
        }
    
      if(test_temp==1)
        {
   //  Serial.print(d1);Serial.print("\t");
   //  Serial.print(d2);Serial.print("\t");
   //  Serial.print(a);Serial.print("\t");
          
      //applying cosine rule to calculate angle    
              float theta=acos((((d1*d1)+(a*a)-(d2*d2)))/(2*d1*a));
              Calc_X[count]=d1*cos(theta)+ Position[i]; // y coordinate 
              Calc_Y[count]=d1*sin(theta);            // X coordinate  
              test[count]=1;  
           //   Serial.print(Position[i]);Serial.print("\t");
        }  
 // Serial.print(Calc_X[count]);Serial.print("\t");
 // Serial.print(Calc_Y[count]);Serial.print("\t");
 // Serial.print(test[count]);Serial.print("\n");

      count=count+1;   
    } 
  }
}



//-------------------------------------------------------------------------------------//
// this function check if triangle is possible our not for selected combination of sensor data
int check(float d1,float d2,float a) 
{
  int temp_test;
if(d1>d2+a || d2>d1+a  ||  a>d2+d1){return 0;}
else{return 1;}
}


//-------------------------------------------------------------------------------------//
//this function combines data of various sensor data combination with
// weitage as per accuracy of perticular combination
// and proportional to distance in between sensors
void Fuse_data()
{
float temp_sum=0;
int count=0;
Final_X=0;
Final_Y=0;
for(int i=0;i<n;i++)
    {
    for(int j=i+1;j<n;j++)
      {
        if(test[count]==1){temp_sum=temp_sum+Position[j]-Position[i];}
   
        Final_X=Final_X+Calc_X[count]*test[count]*(Position[j]-Position[i]);
        Final_Y=Final_Y+Calc_Y[count]*test[count]*(Position[j]-Position[i]);
        
        count=count+1;
      }
    }
    
  Final_X=Final_X/temp_sum;
  Final_Y=Final_Y/temp_sum;

}

Tracking with 2 sensor

Arduino
float  X,Y;
void setup() {
    Serial.begin(9600); // Starting Serial Terminal

    
    pinMode(8, OUTPUT);   
    pinMode(7, INPUT);
    
    pinMode(4, OUTPUT);
    pinMode(6, INPUT);
}

void loop() 
{
Track();
Serial.print(X);
Serial.print("\t");
Serial.println(Y);
}



//------------Function For Object Track with Ultrasound------------//
//this method use triangulates Position of object by Using measurement 
// of two ultrasound sensor saperated by known distance.
//output is based on mid point of two sensor
//for more details refer following link
//
//             by-ABHILASH

void Track()
{
   float d1,d2,theta;
   float dist=81; //distance between two sensors

   //pins for sensor 1 need to be uploaded
   digitalWrite(8, LOW);
   delayMicroseconds(2);
   digitalWrite(8, HIGH);
   delayMicroseconds(10);
   digitalWrite(8, LOW);
   d1 = pulseIn(7, HIGH);
   d1=d1*343/2000;

  
   delay(10);
   //pins for sensor 2 need to be uploaded
   digitalWrite(4, LOW);
   delayMicroseconds(2);
   digitalWrite(4, HIGH);
   delayMicroseconds(10);
   digitalWrite(4, LOW);
   d2 = pulseIn(6, HIGH);
   d2=d2*343/2000;
  
theta=acos((((d1*d1)+(dist*dist)-(d2*d2)))/(2*d1*dist));

if(theta<3 && theta>0){               // to avoid impossible values
  X=d1*cos(theta)+ dist/2; // y coordinate 
  Y=d1*sin(theta); // X coordinate
}
else{Serial.println("bad track");}
/*Serial.print(d1);
Serial.print("\t");
Serial.print(d2);
Serial.print("\t");
Serial.print(theta*180/3.14);           //for debugging
Serial.print("\t");
Serial.print(X);
Serial.print("\t");
Serial.print(Y);
Serial.print("\n");*/
delay(10);

}

Credits

abhilash_patel

abhilash_patel

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