The framework to build a cheap circular LED display. This is based around the led matrix displays using the MAX7219 driver chip, these boards cost about £1 each and can be found on ebay by searching for MAX7219. The display is driven from a microcontroller such as an Arduino. There is a bracket to mount an Arduino Uno to the top or bottom of the display, assuming you use 16 display segments. Display overview and build - https://www.youtube.com/watch?v=cu6kMsd_Y8MThe display can use any number of screens but it is designed for 16, if you use more or less than this the flat brackets won't work as they are very specific with the hole separation. The smaller clips can accommodate a bit of variation but probably only +- 2 displays. For a bit more info there is an instructable for this. http://www.instructables.com/id/Circular-LED-Display/