User:Sorceror Nobody/Sandbox2

Basic hopper clock
To create a switchable 4-clock (more or less), you can set up 2 hoppers facing each, drop an item in one hopper, and use a redstone comparator as the output. Four hoppers in a circular pattern will give a period of 16, but this is not properly an 8-clock, because the output will be "on" 4 only ticks out of 16. A switch can power the side of the comparator, to cut off output, or one of the hoppers, to stop the transfer itself. Note that in the schematic, the switch as positioned will power the hopper only; it would need redstone dust to power the comparator. Note that since it uses a comparator, building this in survival mode requires access to Nether Quartz.

Long period hopper clock
The basic principle of the above clock can be extended to create adjustable hopper clocks with periods of up to several minutes.

If the comparator output from a hopper in the loop is fed into the next hopper along, it prevents the items in the second hopper from passing into the third hopper until the first hopper has completely emptied into the second. This allows the period to be controlled by the number of items in the hoppers, whereas ordinarily, only one item will travel around the loop regardless of how many are stored.

The size of the design shown is 7x8x2. With this design, a pulse is output every  seconds, where   is the total number of items in the hoppers. From this, it follows that, with a single hopper able to store five stacks,

Switching the lever on halts the output and, eventually, the hoppers. The switch is also capable of forcing a pulse (triggered on the lever's falling edge), but this is not an entirely reliable feature, as it only works if the hopper nearest the lever is empty.

Variations

If the circuit is not required to output short pulses, the incorporated falling edge pulse generator can be removed (reducing the footprint to 6x6). The period of the clock will be unaffected by this change, but the output pulses will have a duration of  seconds (a quarter of the clock period).

It is also possible to remove two of the four comparator/repeater circuits, if the user wishes to save on resources, but the clock still requires all four hoppers, and the comparators removed must be on opposite sides of the hopper loop. This alteration also approximately halves the period, changing it to  seconds, with a maximum of   seconds (4m 16.8s).