Mood lighting with Raspberry Pi
Mood lighting or ambience lighting refers to using different colors of light to create an ambience reflecting a particular mood. With incandescent or CFL bulbs, mood lighting was very restrictive - color of the light would be restricted to the color of the enclosure of the bulb. However advent of RGB (Red Green Blue) LEDs has opened up a new dimension in mood lighting. A good example is Philips Hue (http://www2.meethue.com/en-xx/). Not only one is not restricted by the color of the enclosure, one gets a choice of colors not previously possible which can be dynamically changed too!! If you don't want to invest in a proprietary solution, here's one way to achieve the same using RGB LED strip and RPi. Hardware A typical RGB strip needs 12V. However, RPi provides only 3.3V at the GPIO pins. Hence we need a bridge between these two circuits. A ULN2803 chip acts as this bridge - it takes TTL input and allows one to drive a high voltage circuit. Software We ...