by QcTH, published
This is a unique clock design. You can tell time with by looking at a series of twelve pegs on top of the clock, or with the LCD screen, if you need a more precise time. As time passes, a belt with a bump on it passes under the pegs (all happens hidden inside it) and rises them. One pass from left to right takes 12 hours, after which it takes another twelve hours to do it from right to left.
You can read time by looking at the pegs. If it's AM, then, if the second peg from the left is up, it's 2 AM. If it's PM, then it's the opposite : the second peg on the left means 10 PM. Take a look at my images, one explains it better.
To be build with a MakerBot in plastic. Time control works with an Arduino, linked to an external time keeping device (for more precision). The controller turns a 1 rotation per hour motor for 12 hours in one direction, then in the other direction for 12 hours. For even more precision, a full turn, free turning potentiometer can be connected to the output of the motor to calculate through the controller the speed of the motor, and then do any appropriate modification to speed.