Have you ever come home at night and realized you forgot to turn your outdoor light on? It makes it very difficult to find your keys and unlock your door. Or maybe you just don't want to have to keep your light on all day while you are out, just so you can use it when you arrive home. Well the Keylight can solve your problem. The Keylight system involves a force sensing doormat, light sensor, and light bulb. When you arrive home and step on the door mat the light by your door will turn on to help you find your keys and unlock your door. Additionally, the light sensor will be able to tell how much sunlight there is, and only turn your light on if it is necessary. This device is great to help you get in the door at night without having to waste electricity by leaving your light on all day.
Provided below are photos of the circuit and the status of the sensors and light for three different situations. The first, when no one has stepped on the door mat (activated the force sensor), the light remains off. The second, when the mat is stepped on, but it is still daytime and the light is not needed (the photoresistor reads a value higher than 100), the light still remains off. The third, when the door mat is stepped on and it is night time, the light remains on while you are at your door.