// master
#include <Wire.h>

char comeMove;
char comeLat[10]={}; 
char comeLong[10]={}; 
char comeTargetLat[10]={}; 
char comeTargetLong[10]={}; 

void setup() {
    Wire.begin(); 
    Serial.begin(9600);  
}

void loop() {
    receiveFromSlave();
    delay(1000);
}

// função para receber dados do slave
void receiveFromSlave() {
    Wire.requestFrom(8, 41);    
    int i=0; 
    while (Wire.available()) { 
      Serial.print(Wire.read());
      	/*if (i < 1) {
            comeMove = Wire.read(); 
        } 
        else if (i < 11) {
            comeLat[i-1] = Wire.read(); 
        }
        else if (i < 21) {
            comeLong[i-11] = Wire.read(); 
        } 
        else if (i < 31) {
            comeTargetLat[i-21] = Wire.read(); 
        } 
        else {
            comeTargetLong[i-31] = Wire.read(); 
        }
        i=i+1;*/
    }
    Serial.print("Move = "); 
    Serial.println(comeMove);  
    Serial.print("Latitude = "); 
    Serial.println(comeLat);  
    Serial.print("Longitude = ");
    Serial.println(comeLong);  
    Serial.print("targetLatitude = "); 
    Serial.println(comeTargetLat);  
    Serial.print("targetLongitude = ");
    Serial.println(comeTargetLong); 
    delay(500);
}

********************************************************************

// slave
#include <Wire.h>

char goMove[1]={};
char goLat[11]={}; 
char goLong[11]={};
char goTargetLat[11]={}; 
char goTargetLong[11]={};
char dataToSend[45]={};
float move = 1;
float latitude = -11.111111;   
float longitude = -22.222222;
float targetLatitude = -33.333333;
float targetLongitude = -44.444444;

void setup() {
    Wire.begin(8);                
    Wire.onRequest(requestEvent); 
    Serial.begin(9600);  
}

void loop() {
    gatherData();
	delay(1000);
}

// função para reunir os dados na variável a ser enviada
void gatherData() {
    memset(dataToSend, 0, sizeof(dataToSend));
    dtostrf(move, 1, 0, goMove);
    dtostrf(latitude, 3, 6, goLat); 
    dtostrf(longitude, 3, 6, goLong);
    dtostrf(targetLatitude, 3, 6, goTargetLat); 
    dtostrf(targetLongitude, 3, 6, goTargetLong);
    strcat(dataToSend, goMove);
    strcat(dataToSend, goLat);
    strcat(dataToSend, goLong);
    strcat(dataToSend, goTargetLat);
    strcat(dataToSend, goTargetLong);
    Serial.println(dataToSend);
}

// função para enviar dados ao master quando solicitado
void requestEvent() {
    Wire.write(dataToSend);
}