Redstone Basics: From Torch to Clock Circuits

Signal and signal strength

Redstone dust carries a signal with strength from 15 (at the source) down to 0, losing 1 per block. Sources: lever, button, pressure plate, redstone torch, block of redstone, observer, comparator, target block.

• Lever: constant signal, on/off.
• Button: a pulse (stone 1 s, wooden 1.5 s).
• Observer: a 2-tick pulse when the block in front of it changes.

One redstone tick = 2 game ticks = 0.1 seconds.

The three key components

Redstone torch

An inverter: it stays lit while the block beneath it does not receive a signal. All logic gates (NOT, AND, OR) are built from torches.

Repeater

It does three things: restores signal strength to 15, delays it by 1–4 ticks (right-click), and lets current through in one direction only. A repeater locked from the side by another repeater "freezes" its state: the simplest memory cell.

Comparator

The smartest component:

• Compare mode (front torch off): output = rear signal if it is not less than the side signal, otherwise 0.
• Subtract mode (torch on): output = rear − side.
• Container reading: signal strength 0–15 is proportional to how full a chest, hopper or furnace is. The basis of every item sorter.

Basic circuits

Clock

Two repeaters facing each other, connected with dust, make an endless loop. The comparator version is more compact: a comparator in subtract mode with its output fed back into its own side.

T flip-flop (button toggle)

A button toggles the state: press for on, press again for off. The most compact variant is the hopper-based one: two hoppers facing each other, a single item inside, a comparator reading it, and the button locking one of the hoppers.

Item sorter

A hopper with 41 items of the target type (18 + 1 + 1 + 1 + 1 across the slots, first slot holds 18) + a comparator reading it + a subtracting chain that lets an item pass only when the hopper "overflows". Place them in a row and you get an auto-storage.

Practical rules

1. Build modularly: debug each unit separately, then connect them.
2. A signal doesn't pass through glass, but does pass through top slabs.
3. A powered hopper stops: that's how delays and filters are made.
4. A piston can't pull obsidian or containers; a sticky piston "drops" its block on a pulse shorter than 1 tick (spam pulse); sometimes that's a feature.
5. Re-test contraptions after a version change: quasi-connectivity mechanics and hopper timings occasionally change.

What to build next

An auto-smelter with three hoppers → a 10-type item sorter → an observer-based sugar cane farm → a clock-driven stone farm. Each next project reuses all the previous techniques.