I originally used this idea in fifth grade for Invention Convention. I decided that it would be a good project to put on Instructables.

I first got the idea for this gadget when I noticed that the lights by my garage would turn on when there was still sunlight outside. The light would turn on too early because the sensor that controls the light is beneath the soffit. When the sun begins to set it casts a shadow on it which causes the light to turn on too early in the evening. Similarly, it turned off too late in the morning when it was already bright outside. Also on cloudy days when the sunlight is blocked the light goes on. I decided that something had to be done about these problems because energy was being wasted which could easily be prevented.

This gadget works by reflecting light from the bright sky into the light sensor. After testing I estimated that in my case, I save 30 minutes of energy in one day including dusk, dawn, cloudy and rainy days.

Step 1: Materials

This is a very simple instructable and it is not very hard to make. All you need is:

A metal clamp size 36
Any ordinary wire that can easily be bent, but it holds its shape
A wire connector
A small mirror (In my case I used a periscope mirror. You can also use any small mirror, such as a disposable dental mirror)
Super glue
A screw driver

This should all cost you a little less than five dollars.

Step 2: How to Make It

1.Glue the wire connector to the mirror.
2. Attach the wire to the wire connector.
3.Attach the other end of the wire to the metal clamp.
4.Go outside and attach the metal clamp around the light fixture and put the wire under the clamp.
5.Adjust your energy saving gadget, so that the light doesn't turn on too early.

Step 3: Environmental Impact With This Instructable

I calculated how much energy can be saved for two 100-watt light bulbs with my device when each bulb is turned on for 30 minutes less. Two light bulbs would save one hour of electricity. For different watt light bulbs you need to make an adjustment in the calculation.

Energy used in one year is 36kWh (kilowatt-hours). I am assuming that each house has two 100-watt light bulbs.

In one year the amount of coal to generate this energy for:
- 1 house=30 lbs.
- 1,000,000 houses=30,000,000 lbs ( 15,000 tons).
- 10,000,000 houses=300,000,000 lb (150,000 tons).

Number of 100-ton train cars needed for:
- 1 house: none
- 1,000,000=150
- 10,000,000=1,500

Pollutants released by a regular coal power plant in this case:
Sulfur dioxide:
- 1 House - 0.2 lb
- 1,000,000houses - 200,000 lb
- 10,000,000 - 2,000,000 lb

Nitrogen dioxide:
- 1 house- 0.2 lb
- 1,000,000- 200,000 lb
- 10,000,000- 2,000,000 lb

Carbon dioxide:
1 House- 77 lb
1,000,000- 77,000,000 lb
10,000,000- 770,000,000 lb

If only one house uses my invention then it will not make a big impact on the environment. However if 1,000,000 or even 10,000,000 houses use this, then it could reduce millions of pounds of toxins released into the atmosphere just by the use of such a simple device.

My calculations are based on an article "How much coal is required to run a 100-watt light bulb 24 hours a day for a year?" that I found on the Internet.