TWI/I2C - Arduino to Arduino, sending float

Using Arduino Programming Questions
26

Ok, I've done all you said. It is still not working correctly. I am now going to use I2C_Anything, but I still wonder what the problem here is?

I have now:

Master:

// I2C BUS:

// Constants:
    const byte slaveAddress = 8;
    const byte dataCount = 24;

// Variables:
    union T {byte b[8]; double d;} T;
    union X {byte b[8]; double d;} X;
    union Y {byte b[8]; double d;} Y;

// Functions:
    void readPositions() // Requests coordinates (x and y) and the heading angle (theta) from the slave.
    {
      if (Wire.requestFrom(slaveAddress, dataCount) == dataCount)
      {
        for (byte i = 0; i < 8; i++)
        {
          T.b[i] = Wire.read(); Serial.print(T.b[i]); Serial.print(",");
          X.b[i] = Wire.read(); Serial.print(X.b[i]); Serial.print(",");
          Y.b[i] = Wire.read(); Serial.print(Y.b[i]); Serial.println();
        }
        Serial.println();

        t = T.d; x = X.d; y = Y.d;

        // Serial.print(t); Serial.print(",");
        // Serial.print(x); Serial.print(",");
        // Serial.print(y); Serial.println();
      }
    }

Slave:

// I2C BUS:

// Constants:
    const byte myAddress = 8;
    const byte dataCount = 24; // [bytes] Max:32

// Variables:
    union T {byte b[8]; double d;} T;
    union X {byte b[8]; double d;} X;
    union Y {byte b[8]; double d;} Y;
    byte data[dataCount];

// Functions:
    void writePositions() // The function that executes whenever data is requested by master.
    {
      T.d = t; X.d = x; Y.d = y;

      for (byte i = 0; i < 8; i++)
      {
        byte j = i * 3;
        data[j]     = T.b[i]; Serial.print(data[j]); Serial.print(",");
        data[j + 1] = X.b[i]; Serial.print(data[j + 1]); Serial.print(",");
        data[j + 2] = Y.b[i]; Serial.print(data[j + 2]); Serial.println();
      }
      Serial.println();

      Wire.write(data, sizeof data);

      // Serial.print(t); Serial.print(",");
      // Serial.print(x); Serial.print(",");
      // Serial.print(y); Serial.println();
    }

Outputs are:

Slave:
249,17,126
186,201,27
131,71,189
155,55,202
120,75,69
31,153,120
25,165,245
64,191,62

Master:
64,249,17
126,186,201
27,131,71
189,155,55
202,120,75
69,31,153
120,25,165
245,64,255