The SEWRGB v2.0 pixel is a sewable RGB pixel for wearable projects. The boards are available for purchase from my Tindie store.
At the heart of the SEWRGB pixel is a WS2812 LED. The WS2812 is an interesting device which has a SMD5050 RGB LED combined with a built in WS2811 controller chip. This chip controls the current to each of the internal LEDs and using PWM can produce 24-bit colour.
Many SEWRGB pixels can be daisy-chained into strings that can all be individuality controlled by a single pin on a micro controller.
Note for designs which use lots of pixels you need to plan and layout the circuit carefully. As depending on the colour patterns shown, up to ~60mA of current might be needed for each pixel. You power supply (battery) needs to be able to supply about number of pixels * 60mA. Also with such high current demands a voltage drop can occur from the resistance of conductive thread used, causing a noticeable dimming of the LEDs. So plan to use a low resistance Stainless Steel Thread or many strands of Silver Coated Thread, or even thin Stranded Copper Wire.
The SEWRGB pixels are software compatible with the Adafruit NeoPixel Arduino library. They have been used with the LilyPad Arduino and Adafruit Flora wearable micro controllers.
The board is 14mm in diameter with a thickness of 1.6mm and supplied pre-assembled.