by engunneer, published
This is a printed frame to hold some LED modules that I bought at American Science and Surplus. The modules were originally intended for a Cricket (darts) scoreboard, but the rings are made of 4 LEDs each with two LED slashes inside..
I bought the DS1307 kit from Adafruit (http://adafruit.com/products/264) to act as the RTC, and the main PCB is one I designed to hold an Atmega328 which I burned with an Arduino bootloader. Full details and discussion over at my blog (http://www.engunneer.com/content/blog/cricket-clock)
Print both parts and tap the holes for 3mm
Install the LED module and the circuit boards
Wire and program