Television Sensor

These days Kavin has become very careless about switching off the TV. He watches it for some time and goes away either to his room or to play on the PC while the TV is still running. So me and his Appa keeps telling him to switch-off the TV and help in saving the electricity. One day he totally got fed up with our reminders and said-"I want a TV sensor. It should sense that there's nobody in the room and switch-off the TV." Kabi asked him how to make such a sensor.
He said-"We can use the car's reverse-sensors to develop our TV sensor."

Kabi is trying to develop such a sensor using a relay switch and a motion sensor with the help of Kavin, let's see where it goes!