Redstone circuits/Clock/Hopper clocks

Single-item hopper clocks

A single-item hopper clock simply moves a single item in a loop of hoppers.

Hopper-Loop Clock

• Period: 14gt (7rt, 0.7s)‌^{[JE only]} | 16gt(8rt, 0.8s)‌^{[BE only]}
• Pulse lenght: on-pulse: 7gt (3.5rt, 0.35s), off-pulse: 7gt (3.5rt, 0.35s)‌^{[JE only]} | 8gt (4rt, 0.4s), off-pulse: 8gt (4rt, 0.4s)‌^{[BE only]}
• Frequency: ~1.43Hz‌^{[JE only]} | 1.25Hz‌^{[BE only]}
  • 1×3×2 (6 block volume), 1-wide, flat, silent

This clock just bounces an item back and forth between the two hoppers. This clock runs while the input is off, and turns its clock signal output off when the input turns on.

Variations: Another comparator can be added to the other hopper to get another clock signal inverted from the other.

N-Hopper-Loop Clock^[1]

• Period: n*7gt‌^{[JE only]} | n*8gt‌^{[BE only]}
• Pulse lenght: on-pulse: 7gt (3.5rt, 0.35s), off-pulse: (n-1)*7‌^{[JE only]} | 8gt (4rt, 0.4s), off-pulse: (n-1)*8‌^{[BE only]}
• Frequency: ~1.43Hz‌^{[JE only]} | 1.25Hz‌^{[BE only]}
  • 2×(N/2+1)×2 (2×N+4 block volume), flat, silent

An n-hopper-loop clock consists of a loop of hoppers moving a single item around which occasionally powers a comparator output. This clock runs while the input is off, and turns its clock signal output off when the input turns on.

Variations: Other comparators can be added to the other hoppers to get other clock signals out-of-phase with each other.

Multi-item hopper clocks

A multi-item hopper clock achieves longer clock periods by using multiple items in the hoppers, and using a latch to keep the items flowing first one way then the other (rather than just bouncing back and forth between two hoppers).

For most of the multi-item hopper clocks, see the Items Required for Common Clock Periods table (right).

Etho Hopper Clock (EHC)

This compact timer was invented by Minecraft YouTuber EthosLab (also known as Etho), hence the name.

• (Single-item Etho Hopper Clock)
  • First cycle period: 9gt (4.5rt, 0.45s)‌^{[JE only]} | 16gt (8rt, 0.8s)‌^{[BE only]}
  • Following cycles period: 14gt (7rt, 0.7s)‌^{[JE only]} | 16gt (8rt, 0.8s)‌^{[BE only]}
  • First cycle pulse length: on-pulse: 4gt (2rt, 0.2s), off-pulse: 5gt (2.5rt, 0.25s);‌^{[JE only]} | on-pulse: 8gt (4gt, 0.4s), off-pulse: 8gt (4gt, 0.4s)‌^{[BE only]}
  • Following cycles pulse length: on-pulse: 5gt (2.5rt, 0.25s), off-pulse: 9gt (4.5rt, 0.45s)‌^{[JE only]} | on-pulse: 8gt (4gt, 0.4s), off-pulse: 8gt (4gt, 0.4s)‌^{[BE only]}
  • First cycle frequency: ~2.22Hz‌^{[JE only]} | 1.25Hz‌^{[BE only]}
  • Following cycles frequency: ~1.43Hz‌^{[JE only]} | 1.25Hz‌^{[BE only]}
• (Multiple items Etho Hopper Clock)^[2]
  • Period: [(n-1)*8+2]*2gt‌^{[JE only]} | [(n-1)*8+4]*2gt‌^{[BE only]}
  • Pulse lenght: on-pulse: (N-1)x8gt, off-pulse: (N-1)x8+4gt‌^{[JE only]} | on-pulse: (N-1)x8gt, off-pulse: (N-1)x8+8gt‌^{[BE only]}
  • Frequency: 5/[(n-1)*4+1]Hz‌^{[JE only]} | 5/[(n-1)*4+2]Hz‌^{[BE only]}
• 2×6×2 (24 block volume)
• flat

When the items finish moving in one direction, the empty hopper's comparator turns off, allowing the associated sticky piston to pull the block of redstone to the other hopper, reversing the direction of item movement. The movement of the block of redstone also updates the other sticky piston (which has been powered for a while) causing it to extend and prevent the first sticky piston from extending again when its comparator turns back on.

Powering the hoppers will freeze the clock. Powering one of the blocks or the redstone dust will allow the clock to finish its current cycle before halting.

There are a number of useful outputs from this clock:

• Normal output: a regular on/off clock signal can be taken from one position of the block of redstone. The signal will last for half the clock period.
• Comparator output: taking the output from one of the comparators results into an on-pulse that's [(n-1)*8+2]*2-2gt‌^{[JE only]} | [(n-1)*8+4]*2-2gt‌^{[BE only]} long and an off-pulse that's 2gt(1rt) long (when there's more than one item in the clock).

Earliest known publication: January 19, 2013^[3]

EHC Variations

Smoothed EHC

• (Single-item Smoothed EHC)
  • Period: 16gt (8rt, 0.8s)‌^{[JE only]} | 20gt (10rt, 1s)‌^{[BE only]}
  • Pulse length: on-pulse: 10gt (5rt, 0.5s), off-pulse: 6gt (3rt, 0.3s);‌^{[JE only]} | on-pulse: 12gt (6gt, 0.6s), off-pulse: 8gt (4gt, 0.4s)‌^{[BE only]}
  • First cycle frequency: 1.25Hz‌^{[JE only]} | 1Hz‌^{[BE only]}
• (Multiple items Smoothed EHC)^[4]
  • Period: [(n-1)*8+2+d]*2gt‌^{[JE only]} | [(n-1)*8+4+d]*2gt‌^{[BE only]}
  • Pulse length: on-pulse: (N-1)x8gt, off-pulse: (N-1)x8+4+dgt‌^{[JE only]} | on-pulse: (N-1)x8gt, off-pulse: (N-1)x8+8+dgt‌^{[BE only]}
  • Frequency: 5/[(n-1)*4+1+d/2]Hz‌^{[JE only]} | 5/[(n-1)*4+2+d/2]Hz‌^{[BE only]}

Variations: The single-item Etho Hopper Clock can be turned into a 16gt(8rt) clock with a repeater set to 3 redstone ticks. Adding more repeaters on one side of the clock can change its timings.

Other configurations are possible. The "1-Wide Compact" version is 1×6×3 (18 block volume). The "1-Wide Tileable" and "1-Wide Upside-Down" versions are both 1×8×3 (24 block volume).

Hopper timer

								H
		P					p
F

Hopper timer

• Period: 14-5108gt (7-2554rt, 0.7-255.4s)‌^{[JE only]} | 16-5112gt (8-2556rt, 0.8-255.6s)‌^{[BE only][note 1]}
• pulse length: on-pulse: 5-2552gt (2.5-1276rt, 0.25-127.6s), off-pulse: 9-2556gt (4.5-1278rt, 0.45-127.8s)‌^{[JE only]} | on-pulse: 8-2552gt (4-1276rt, 0.4-127.6s), off-pulse: 8-2560gt (4-1280rt, 0.4-128s)‌^{[BE only]}
• Frequency: ~1.43-~0.004Hz‌^{[JE only]} | 1.25Hz-~0.004Hz‌^{[BE only]}

• 9x5x2 (90 block volume)
• flat
• the right hopper contains the counter items (of the stackable-to-64 type).
• four different pulse outputs possible:
  • F once after the whole timer period.
  • H at the half way point.
  • P/p every time the related comparator measures a level change in its hopper.

This Hopper timer is basically just a self-locking EHC with trigger input and a falling edge detector to detect the end of the full timer period.

So it needs to be started by activating the input (= interrupting the self-locking circuit) and will stop on its own after one full clock period. Unless of course the input is powered continuously which will turn it into a regular EHC but with trigger outputs.

(improved by Nilbadimo)

Quick reset EHC

Using the Etho clock as a base, a timer can be created to allow a shorter cool-down time than the clock period.

Normally, a hopper timer would require all items to be transferred back to the original container to be triggered again.

This design uses both sides of the Etho clock and a T flip-flop to create a timer that will be available to use again almost immediately after it has stopped.

Thus, a "quick reset" effect is achieved, without actually resetting the position of the items.

RS NOR Latch Hopper Clock

• 4×6×2 (48 block volume)
• flat, silent
• clock period: 14gt(7rt)‌^{[JE only]} to ~256s (~4m16s) | 16gt(8rt) to ~256s (~4m16s)‌^{[BE only] [note 1]}

A silent multi-item hopper clock which uses an RS NOR Latch to control the direction of item movement.

Earliest known publication: January 19, 2013^[3]

1-Wide RS NOR Latch Hopper Clock

• 1×7×5 (35 block volume)
• 1-wide, silent
• clock period: 14gt(7rt)‌^{[JE only]} to ~256s (~4m16s) | 16gt(8rt) to ~256s (~4m16s)‌^{[BE only] [note 1]}

A 1-wide version of the RS NOR Latch hopper clock.

Hopper-Latch Hopper Clock

• 2×4×3 (24 block volume)
• silent
• clock period: 14gt(7rt)‌^{[JE only]} to ~256s (~4m16s) | 16gt(8rt) to ~256s (~4m16s)‌^{[BE only]}
• The top hopper in the bottom layer contains 1 item.
• The top hopper in the top layer contains multiple items.

A silent multi-item hopper clock which uses a hopper latch to control the direction of item movement.

Earliest Known Publication: March 18, 2013.^[5]

SethBling's Hopper Clock

• 6×6×2 (72 block volume)
• flat, silent
• clock period: 1.6 seconds to 512 seconds (8m32s)

A loop of hoppers with multiple items, where each hopper prevents the next hopper from pushing items further until the previous hopper has emptied.

This clock can create a clock signal twice as long as the other multi-item hopper clocks. However, in less space players could build a multiplicative hopper-dropper clock with a clock period hundreds of times longer.

Variations: The "simplified" version uses slightly fewer resources, by simply replacing the repeaters with blocks. The "amputated" version (two "arms" have been removed) only goes up to 256 seconds, but is one-third the size.

Earliest known publication: January 22, 2013^[6]

Multiplicative hopper clocks

A multiplicative hopper clock uses a hopper clock to regulate the item flow of secondary stages to produce very long clock periods (the secondary stages "multiply" the clock period of the first hopper clock).

Multiplicative Hopper Clock (MHC)

Multiplicative Hopper Clock

• 5×6×2 (60 block volume)
• flat
• clock period: up to 45 hours

The repeaters in the middle keep the bottom hopper clock from transferring items except for the brief period when the top hopper clock reverses direction. Thus, the bottom hopper clock will transfer 1 item every time the top hopper clock completes a full cycle (except when the bottom clock reverses direction, when the bottom clock transfers an item after only half a cycle).

The bottom clock will have a clock period of X × (2Y - 1) × 0.8 seconds, where X is the number of items in the top clock and Y is the number of items in the bottom clock (both max. 320 items).

Multiplicative Hopper-Dropper Clock (MHDC)

• 5×6×2 (60 block volume)
• flat
• clock period: up to 81.9 hours (3.4 real-life days)

The top part is a regular Etho Hopper Clock. Once per cycle, the block of redstone will move left and activate both of the droppers in the second stage (the left dropper is powered directly, while the right dropper is activated because it's next to a powered block: the left dropper). The block of redstone in the second stage ensures that only one dropper will actually push an item, forcing the items to move in one direction until the block of redstone moves.

The dropper clock multiplier will have a clock period of X × Y × 1.6 seconds, where X is the number of items in the hoppers (max. 320 items) and Y is the number of items in the droppers (max. 576 items).

Items Required for Useful Clock Periods
Period	Hoppers	Droppers
10 minutes	75	5
20 minutes	75	10
30 minutes	75	15
1 hour	225	10
2 hours	300	15
3 hours	225	30
6 hours	300	45
12 hours	300	90
24 hours	300	180
48 hours	300	360
72 hours	300	540

Variations: The most compact version of this circuit (2×6×4 = 48 block volume) can be achieved by moving the first stage above the second stage, and rotated 180°, with a single piece of redstone on one of the droppers. Each additional dropper stage should be rotated 180° to the one above.

Each additional dropper stage can multiply the previous stage's clock period by up to 1,152 (twice the number of items a dropper can hold). Adding just one additional dropper stage increases the maximum clock period to over 10 years. In practice, this may only be needed for clock periods measured in weeks or months (longer than the 2-stage version can provide), generally on servers.

2-Stage MHDC (without Sticky Pistons)
Q Level 1 (bottom layer)	Level 2 (top layer)
8x4x2 (64 block volume) 2 high, no sticky piston, multiplicative clock period: up to 81.9 hours (3.4 real-life days)[note 1] The right hopper and right dropper contain multiple items. (This is a combination of the 2-Stage MHDC and the Modified Etho Hopper Clock)

Multiplicative Hopper-Latch Clock (MHLC)

4×5×3 (60 block volume)

silent

clock period: up to 81.9 hours (3.4 real-life days)

The MHLC uses hopper-latch hopper clocks for each stage, replacing the top hoppers in the secondary stage with droppers, and connecting the stages with a comparator to pulse the secondary stage.

The MHLC uses the same number of items as the MHDC for the same clock periods, with a similar volume, but is silent.

Variations: Each additional dropper stage can multiply the previous stage's clock period by up to 1,152 (twice the number of items a dropper can hold).