HOPPER CLOCK
Two hoppers facing each other with items bouncing between them. A comparator reads the item count to generate a signal. Clock period depends on the number of items.
When to Use
Long-period clocks for daylight cycles, slow farms, timed events that need minutes between pulses.
Materials
- ▸2 Hoppers
- ▸2 Redstone Comparators
- ▸Redstone Dust
- ▸Items (any stackable)
- ▸Solid blocks
Overview: what the Hopper Clock is and does
Two hoppers facing each other with items bouncing between them. A comparator reads the item count to generate a signal. Clock period depends on the number of items.
As a clock it produces a repeating on/off pulse on its own, driving anything that needs to fire at a steady rhythm.
In practice it is used for long-period clocks for daylight cycles, slow farms, timed events that need minutes between pulses. The build below targets vanilla Java Edition 1.21.
How it works: the redstone mechanics
Items shuttling between two opposed hoppers move one item every 8 game ticks (0.4s), so the period scales directly with how many items you load — a few items give seconds, a full inventory gives minutes. A comparator reads the fullness change to emit the clock pulse.
It is assembled from 2 Hoppers, 2 Redstone Comparators, redstone Dust, items (any stackable), and solid blocks, and each of those parts plays a specific timing or logic role in the circuit rather than being interchangeable filler.
Because this is a clock circuit, the thing to watch as you build is the period — the total tick delay around the loop sets how fast it runs.
How to build it
- 1Place two hoppers facing each other (shift-click placement).
- 2Put a comparator reading out of each hopper.
- 3Place items in one hopper (more items = longer period per side).
- 4The items transfer back and forth; comparators detect fullness changes.
- 5Use the comparator output as your clock signal.
- 6Add a lever to one hopper to lock it and pause the clock.
- 7Power it up and watch one full cycle: confirm it pulses at the rhythm you expected before wiring it into a larger contraption.
Uses & applications
- ▸Long-period clocks for daylight cycles, slow farms, timed events that need minutes between pulses.
- ▸Single-comparator hopper clock (simpler, one output) — a variant suited to particular space or timing needs.
- ▸Multi-hopper chain (for extremely long periods) — a variant suited to particular space or timing needs.
- ▸Adjustable hopper clock (add/remove items to change period) — a variant suited to particular space or timing needs.
Tips & common mistakes
- !Because transfer is item-paced it is slow by design; never reach for a hopper clock when you actually need a fast pulse.
- !If the clock will not be running constantly, add a lever in the loop so you can switch it off and spare the server the block updates.
- !Remember that bare redstone dust loses 1 signal strength per block, so insert a repeater before any run exceeds 15 blocks inside this circuit.
Hopper Clock FAQ
What is a Hopper Clock used for?
A Hopper Clock is used for long-period clocks for daylight cycles, slow farms, timed events that need minutes between pulses. As a clock it produces a repeating on/off pulse on its own, driving anything that needs to fire at a steady rhythm.
What do you need to build a Hopper Clock?
You need 2 Hoppers, 2 Redstone Comparators, redstone Dust, items (any stackable), and solid blocks. Place two hoppers facing each other (shift-click placement).
How does a Hopper Clock work?
Items shuttling between two opposed hoppers move one item every 8 game ticks (0.4s), so the period scales directly with how many items you load — a few items give seconds, a full inventory gives minutes. A comparator reads the fullness change to emit the clock pulse.
Are there different versions of the Hopper Clock?
Yes — common variants include single-comparator hopper clock (simpler, one output), multi-hopper chain (for extremely long periods), and adjustable hopper clock (add/remove items to change period). Pick the one that fits your available space and timing requirements.