To display a clock on 5 x 1m strips of addressable LEDs using an arduino:

Updated (December 2018) It now accounts for daylight saving time, changes colour every hour and shorting pin 12 to ground will turn the LEDs off - intended for use with a door switch or movement sensor.
Changing the colour scheme is very easy and it would be simple to use more LEDs for larger and clearer numbers.
Be sure to use a power supply with sufficient amps and connect it to the led strip, not through the Arduino's power socket. Flickering LEDs are a sign of low voltage.

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