This instructable show us how to build the smallest USB led! It uses a USB plug made with a piece of perfboard, a resistor and of course a led. Basic soldering skills are required to build your own. Follow the instructions on the link below.
The Smallest USB LED - [Link]
This project shows how to build a mood vase using a battery powered unit. The unit shines different colors using three leds and a PIC12F683 microcontroller. It’s easy to follow the instructions below to build the unit as schematic and source code are included.
Mood vase – [Link]
This project shows how to modify an IKEA Lampan lamp to display RGB colors. It uses RGB LEDs and Atmel ATTiny1313 AVR. With the push of a button you can choose the desired color. You can find design files, schematic, PCB and firmware on the link below.
IKEA Lampan RGB LED Light – [Link]
This project shows how to build a LED temperature monitor. It is able to change color depending on room temperature. It is using an RGB led to display colors, an analog temperature sensor and a frosted glass sphere. The result is a high visible room temperature indicator. [via]
Nursery Room Temperature Monitor - [Link]
The circuit above is able to flash a 1.7V or 2.0V LED using 1.5V DC input battery. It is a charge pump design.
1.5V powered LED flasher – [Link]
Instructables user duesentrieb shows us how to build a multicolor flashlight including infrared and ultraviolet. He used a cheap torch found on ebay and some inexpensive parts.
How to build a multicolor flashlight - [Link]
PICtris project is a tetris game using dot led displays controlled by a PIC microcontroller. PIC18LF4520 is drawing 2D graphics on LED display and four buttons control and rotate the blocks. Find schematics and source code on the link below.
PICtris: Tetris on a PIC MCU - [Link]
In this article learn how to drive LEDs using linear circuits, including transistor constant current circuits.
Linear LED power supplies - [Link]
Simon Inns @ Waiting of Friday builds a cool VU meter using RGB leds. RGB leds are controlled by 3 TLC5940 LED driver chips and PIC18F2550 microcontroller. Source code and schematic is available on the link below. [via]
This project creates a RGB LED VU Meter which is controlled via USB by a Windows 7 or Vista host machine. The demonstration board consists of a 5V regulator (switching), a PIC18F2550 with the required USB components, 3xTLC5940 16 channel serial LED drivers with PWM and 16 high intensity RGB LEDs.
RGB LED VU Meter using TLC5940 LED Driver Chips – [Link]