Hello Simon ,

Two years ago i made such a clock with a 8051 micro for my thesis project in the evening school.

You biggest challenge will be to provide power on the spinning arm .
In my case the micro and led 's where mounted on the arm .
I used a home made flyback transformator to forsee everything with power. The primary winding was fixed,the secundary winding was rotating into the primary with a small airgap.
I got this idea from Henk Soubry . You can find more of this on his website:
http://home.tiscali.be/henkenkat...llerclock/

Advantage of this is that you don't need mechanical parts for distrubution of the supply.

I can give you the advice to use some leds with verry high intensity (22000mcd or something) . You can drive them with low current and still have enough brightness.

You can write your software straight forward and should not be a big problem if you study your 8051 courses well.

If you wan't , i can sent you some photo's of the transformator.

Succes and good luck.

Luc Vandenborre