The Grand Clock is a contraption designed by MTM that has the same purpose of the clock item, on a way bigger scale. it was built on November 2013.
A big cage contains all it's circuitry, which is wired with slab bridges to a big dial with redstone lamps, labelled as different parts of the day: Sunrise, morning, noon, afternoon, sunset, night, late night, early morning, and dawn.
An equally purposed clock was (long time) later fitted by Molster inside Hans_Krebs 's obelisk, making the Clock Tower , although it ha 8 lamps instead of the 10 of the grand clock, and it's circuitry is based on command blocks, instead of the analog redstone gates on this one.
The grand clock is actually, two independent light meters on the same enclosure, with one having it's light sensors covered, to make it a nightlight meter.
As the sun rises , the power given by the day sensor rises, lighting the furthest redstone lamp reached by the signal, and turning off the ones that were on before it.
When the day reaches the noon, the day sensor gives all it's power, and activates a gate that switches from the AM set of lamps to the PM set of lamps (making it go from state 0 to 1, as a 1 bit binary memory), so after the noon lamp, the afternoon lamp comes on, instead of the morning lamp as the Voltage decreases. After the sunset lamp, the day sensor gives no power, making the AM-PM gate go back to 0 state (AM)
The night period works exactly like the day one, but using covered daylight sensors.
The clock has two periods where no lamp on it's dial is on, and it's a transition period where none of it's sensors gives any signal, at this moment an idiot light will come on inside it's cage, indicating that both of it's 1 bit binary memory gates have been reset to 0, this happens before sunrise and after sunset.