You probably don’t know what I’m talking about because you probably don’t go to boarding school. In the dorms (bedrooms) everyone talks at night. You lose your break time if you’re caught talking. So Room guard xtra protection (the best version) scans the corridors for teachers and tells you if you are being too noisy. How? Well RGXP consists of two NXTs. One in the dorm, and one placed outside the dorm in the corridor. The one in the dorm has two lights. Green light is OK amount of noise and blue too much or no lights STOP TALKING IT’S THE TEACHER! How does it measure the sound. Well outside the nxt in the corridor has a sound sensor. If it can “hear” you then you’re too loud and it tells the nxt in the dorm to show the blue light. If the nxt sees someone in the corridor then it tells the nxt to switch off the light.