Rex to Arduino

#include <Wire.h>
const int sensorPin = 7;
int sensorValue = 0;
void setup () {
  Wire.begin(4);
  Wire.onRequest(requestEvent);
}
void loop() {
  delay(500);
  sensorValue = analogRead(sensorPin);
}
void requestEvent() {
  uint8_t data[1];
  data[0] = (uint8_t)sensorValue;
  Wire.write(data, 2);
}