20/01/08 - RGB Led Mood Light Lamp:

This is a modded IKEA lamp. I removed the light bulb and fitted the lamp with a 1-watt RGB led driven by a microcontroller (Microchip PIC16F84).
The device includes a 1-wire thermometer and an ethernet interface (with a TCP/IP stack).
- Thermometer mode: lamp changes its color depending on the ambient temperature.
- Ethernet mode: one can remotely control the color of the lamp, or automatically switch from color to other depending on events (ie: blinks when you have unreaded emails - like Nabaztag)

How it works: each led (red, green, blue) is driven by an output of the microcontroller, through a transistor.
To get all the colors from the visible spectrum the intensity of each led (color) is defined by the flicking rate of each led (Pulse Width Modulation).
Note: It would probably have been easier to choose a microcontroller which has 3 PWM output instead of calculating the timings in tight loops...

Click on the video to watch the "rainbow effect".

The (simplified) schematic

1W Star PCD RGB led.
These tiny bonding wires can handle 400 mA each !

Any question ? fblancp@9online.fr