You don't have to be in Times Square to enjoy large bright displays of lights. You can create that in the comfort of your own home with some foam board, LEDs, and our little friend Arduino.
My sister-in-law decided to get married on New Year Eve, and the venue she chose stays open until 1am that night, so I started thinking it would be great to have a nice big countdown clock. I ran the idea past her and her fiance and they both loved it, so I went to work.
When I made it I intended it for just one use, but it's a very impressive display that can be seen across a huge room. This is pretty simplified and what I'm showing you is on a breadboard. Optimizing and taking it beyond prototyping (e.g. replacing the breadboard with some pcb boards) are outside of the scope for this but shouldn't be too difficult.
Step 1: Gather Materials
1 20"x30" piece of foam board (any desired color - my sister-in-law was even considering one of those holographic ones for a short while), we're using plain white in this example
1 roll of 12v LED strips (any desired color) (120 LEDs/m recommended but not mandatory)
1 Arduino (I'm using the UNO R3)
14 2N3904 NPN Transistors
14 1Kohm Resistors
1 7805 Voltage Regulator
1 12v power source (plug or battery)
1 Soldering iron
Enough wire and solder to connect everything, including jumper wires (I used about 50 the first time)
(optional) 2 seven-segment display modules, if you want to tweak the design before taking it full scale. I'm providing a diagram on how to connect to a typical common cathode display.
(optional) Conductive copper tape
(optional) Liquid electrical tape