byte variable[7];
byte index = 0;

void setup() {
  Serial.begin(200);
}

void loop() {
  while (Serial.available() > 0) {
    byte b = Serial.read();
    variable[index++] = b;
  }
  if (index == 7) {
    Serial.print("variable 0: "); Serial.println(variable[0], HEX);
    Serial.print("variable 1: "); Serial.println(variable[1], HEX);
    Serial.print("variable 2: "); Serial.println(variable[2], HEX);
    Serial.print("variable 3: "); Serial.println(variable[3], HEX);
    Serial.print("variable 4: "); Serial.println(variable[4], HEX);
    Serial.print("variable 5: "); Serial.println(variable[5], HEX);
    Serial.print("variable 6: "); Serial.println(variable[6], HEX);
  }

}