LDR - Laser Pointer

Major Interactive - Second sensor 

* Materials :

- an LDR (photoresistor);

- an LED;

- a resistor (100 Ω);

- 3 volts battery.

* The connection results : LED lights up when there is light (A shadow will make the LED to dim down).

*The reverse connection : LED dims down when there is light (A shadow will make the LED to light up).

* Using laser pointer, light dims.

* Laser pointer off, light lights up.