images are CC BY-NC-SA 3.0
Description: This is the NeoPixel Shield from Adafruit. This Arduino shield is equipped with 40 WS2812 RGB LEDs arranged in an 5x8 matrix with on one pin (Digital #6) needed to control them all.
Each shield is powered by the 5V onboard Arduino supply and as long as you aren't lighting up all the LEDs full power white that should be fine. You can also solder in the included terminal block to attach an external 4-6VDC power supply in case you need more power than what the Arduino provides.
Additionally, you can chain as many of these panels together as you'd like when tiled separetely from the Arduino. For the second panel, connect the DIN connection to the first panel's DOUT, connect the ground pins together and power with 5V. It should be noted that after five or more panels you may run low on RAM if you're using an Arduino Uno.