LDRs or Light Dependent Resistors are very useful, especially in light/dark sensor circuits. Normally the resistance of an LDR is very high, sometimes as high as 20000 ohms, but when they are illuminated with light resistance drops dramatically.
Specification:
Can be used to sense Light
Easy to use on Breadboard or Perf Board
Easy to use with Microcontrollers or even with normal Digital/Analog IC
Small, cheap, and easily available
Dimension 10mm
