this is a picture on how to setup the wiring and the photo resistor and the LED light. if you hook it up identical to this it will work fine.

Step 1: Materials List

1. arduino

2. LED light

3. bread board

4. wires (20ga)

5. Photo resistor

6. regular resistor

7. power source

Step 2: Programming

Night_Light.ino
Download

Step 3: Functioning Night Light

when the photo resistor is covered to simulate being in the dark, the light comes on. this is made possible by programming it with an "if, else" statement that states if the sensor senses dark it turns the light on and if it senses there is light the LED turns off.