Add sanity check

crawler_software/arduino/crawler_slave/crawler_slave.ino

@@ -33,6 +33,7 @@ void loop() {
 
 // This method runs when we receive a message
 void receiveEvent(int n) {
+  if (Wire.available() == 2) { // Dont do anything if this is not true
     id  = Wire.read(); // ID of the servo/device to access
     val = Wire.read(); // Value to assign
   
@@ -42,3 +43,4 @@ void receiveEvent(int n) {
         break;
     }
   }
+}