Lesson 6 - Light Sensor

A light sensor is actually a resistor that changes its resistance according to how much light is hitting the sensor area.

The Arduino will send power to the light sensor and measure how much is coming back.  The difference can be used to detect how much light is present.

The light sensor can work either way you put it in.

Similar to buttons, another input option, you will need a 10k Ohm resistor to use this.