RGB LED Fading with Arduino

In this tutorial an RGB LED is interfaced with Arduino Uno and then it is used to fade the LEDs of different colors one by one.

In fact there are two different types of RGB LEDs - common cathode type (common negative) and common anode type (common positive). In CC (Common Cathode or Common Negative), there will be three positive terminals each terminal representing a color and one negative terminal representing all three colors. The internal circuit of a CC RGB LED can be represented as below.

Here you can see the demonstration video of fading RGB LEDs:

See here the full project: Arduino RGB LED Tutorial

Emergency Light Circuit

In this emergency light circuit, when the Power goes OFF, the emergency light activates automatically. We have used four bright white LEDs, more LEDs can be added to produce more light considering that total current consumption should not exceed the supply current. Ultra bright white LED consumes 3v and 20mA current.

See here the full article with circuit diagram: emergency light circuit