NRF24l01 receiving problems

Floats are ugly when they are dumped as ASCII.

Serial.write((byte*)&allData, sizeof(allData));

try

Serial.print(F("temperature "));
Serial.print(allData.temperature);
Serial.print(F(", pressure "));
Serial.print(allData.pressure);
Serial.print(F(",  altitude "));
Serial.print(allData.altitude);
Serial.print(F(", humidity "));
Serial.println(allData.humidity);

You could also add a display function to the struct, which should be defined in a .h file,
or at the top of the sketch with the declarations.

    struct Data {
      float temperature;
      float pressure;
      float altitude;
      float humidity;
      void display() {
        Serial.print(F("temperature "));
        Serial.print(temperature);
        Serial.print(F(", pressure "));
        Serial.print(pressure);
        Serial.print(F(",  altitude "));
        Serial.print(altitude);
        Serial.print(F(", humidity "));
        Serial.println(humidity);
      }        
    };

  Data  allData;

  allData.display();