Light sensors are used to measure the current intensity of light in the ambient environment. Light intensity is measured in lumen units depending on the sensor and the amount of light emitted by the source. Lux is also used to indicate the light amount in the environment Lux means the luminous flux per unit area, which is equal to one lumen per square meter. For example, when there is full daylight, the amount of light is around 10000-25000 Lux. During full moon days, the amount of light is around 0.267 Lux.

Light intensity data can help you to automate your lighting system to switch it on or off. Switching off light automatically with your home automation system, where light intensity is high enough to see, will save energy. You can also create your own luminance data table and use it to automate your application to regulate when to switch lights on or off.

There are many sensors compatible with the Intel Galileo pinout. You can either use photocells or digital light sensors...