Sparkfun Electronics Inventor's Kit Manual page 26

Troubleshooting
Sporadically Working
This is most likely due to a slightly dodgy connection with the potentiometer's pins. This can usually
be conquered by holding the potentiometer down or moving the potentiometer circuit somewhere
else on your breadboard.
Not Working
Make sure you haven't accidentally connected the wiper (center pin), the resistive element in the
potentiometer, to a wrong pin!
LED Not Lighting Up
LEDs will only work in one direction. Double check your connections.
Experiment 3: Reading a Photoresistor
Introduction
In Experiment 2, you got to use a potentiometer, which varies resistance based on the twisting of a
knob and, in turn, changes the voltage being read by the analog input pin. In this circuit you'll be
using a photoresistor, which changes resistance based on how much light the sensor receives. You
will read the light value of the room and have an LED turn on if it is dark and turn off if it is bright.
That's right; you are going to build a night light!