People get really lazy after a long day of tiresome work. So when they go to bed, they forget to switch off the light. Here is solution for these people(marked with black arrows and numbers)..This comes with an added advantage of automatic switching off of your alarm clock (marked with red arrows and numbers)..
You climb onto your bed (1) which is hanging by means of a string. This causes the bed to come down to the floor(2) while the 100.01 kg concerte block rises (3). This causes green ball to roll down(4a) as well as the lever to go down (4b). The green ball falls on the floor(5) and the cat jumps off the basket to play with the ball(6), causing the basket to swing (7) and hit the billaird stick. The stick hits the cue ball(8) and the ball goes along the dotted line (9) and hits the red ball which moves and falls into the hole(10). The red ball bounces on the floor(11) and falls on a spring (12). It moves along 12 and falls on spring 13, bounces off it (14) and hits the glowing bulb(15) thus breaking it, and bringing the room to darkness.. Mission Accomplished..
In the morning, the alarm rings and wakes you up. You get off the bed(16) thus causing the bed to rise up (17), the concrete mass falls down(18). This sudden impact causes the lever to rise up(19) which causes the blue ball to fly along the trajectory (20) and smash into the alarm clock (21) breaking it.. Now u dont have to manually switch it off..
Troubleshooting: In case your cat decides to leave your house some day, do not replace the broken bulb from the previous night..
End of a long manual... :D (5 years and 2000 days ago)