Electric Eye
When electric power was first used to light up streets at night, someone in each street became in charge of turning on the light at nights and turn it back off in the mornings. Today electric eyes automatically turn on the lights when it becomes dark. Electric eyes are used for security in the banks, shopping malls, warehouses and industrial buildings. They are also used for safety of workers and automatically stop machinery if the worker takes his hand toward sharp blades. 
Material and instructions
Have hands on electronics and make some electronic circuits using an electric eye. Light sensor, light meter and remote control light are among the items that you may make during your experiments.  You may control any electrical device such as a light or a radio or a fan using an electric eye circuit. Depending on your project plan, you may need some or all of the following:
Photocell, Transistor, Diode, Relay, wire, bulb, socket, battery, mounting board.
Details of this project
More information or support on this project is available for the members of ScienceProject.com. You may also find a Science kit for this topic at MiniScience.com.