Redstone for Beginners: How Signals Actually Work
Every redstone circuit is a power source, a wire and a device. Dust carries a signal of up to 15 that loses one per block, so a line dies after 15 blocks.
Between the source and the device, repeaters, comparators and torches reshape the signal, and a plain block such as Stone can pass it along.
Power sources: what switches a circuit on
Most sources give 15; they differ in how long they stay on.
| Source | Signal | Stays on |
|---|---|---|
| Lever | 15 | Until flipped back |
| Stone Button | 15 | 1 second |
| Wooden buttons (Poplar too, since 26.3) | 15 | 1.5 seconds |
| Redstone Torch | 15 | Always, unless its block is powered |
| Block of Redstone | 15 | Always |
| Stone Pressure Plate | 15 | While a player or mob stands on it |
| Wooden pressure plates (Poplar too, since 26.3) | 15 | While almost any entity, even an item, is on it |
| Light Weighted Pressure Plate | 1 per entity, up to 15 | While entities are on it |
| Heavy Weighted Pressure Plate | 1 per 10 entities (rounded up), up to 15 | While entities are on it |
| Tripwire Hook | 15 | While an entity touches the String between hooks |
| Daylight Detector | 0 to 15; inverted under open sky, 11 on a clear night | Follows daylight, or darkness when inverted |
| Target | 1 to 15, higher near the centre | 0.4 seconds, or 1 second for arrows and tridents |
Levers, buttons and tripwire hooks also strongly power the block they are fixed to, and a pressure plate the block beneath it. So a button on one side of a Stone block can feed dust on the other.
How Redstone Dust carries a signal
The first dust carries the source's strength and each block after it one less. From 15, the sixteenth block gets nothing, so a long line needs a repeater every 15 blocks. A signal of 5 fades after 5 blocks.
Strength does not change what a device does: a piston fed 1 extends like one fed 15. It only decides how far the signal reaches along dust and what a Redstone Comparator reads.
Dust follows four placement rules:
- It bends toward power, not devices. Dust points at sources, repeaters, comparators and other dust, never at a lamp, door or piston, so a line running past a lamp leaves it dark. Run it into the device or over its top.
- A lone dust is a plus sign that powers all four sides. Use it once and it becomes a dot that powers only the block beneath it.
- It climbs one block at a time. Dust runs up and down a staircase, but a conductive block (stone, dirt, planks) directly above the lower dust cuts the connection.
- Glass and slabs are one-way. Dust sits on Glass, Glowstone, upside-down slabs and stairs, and hoppers, but a signal only climbs these, never descends.
Strong power and weak power
Most full solid blocks, such as stone, dirt and wood, are conductive: they can be powered and pass that power on. Glass, slabs, stairs, leaves, fences and walls are non-conductive, and so are a Block of Redstone, an Observer and a Piston: they never pass power on. A powered conductive block triggers devices touching it and repeaters pointing away from it, but lights dust beside it only when strongly powered.
| What powers the block | Type | Lights dust next to it |
|---|---|---|
| Dust on top of it or pointing into it | Weak | No |
| A repeater or comparator facing into it | Strong | Yes |
| A Redstone Torch directly under it | Strong | Yes |
| A lever or button on it, or a pressure plate on top | Strong | Yes |
So a dust line that runs into a block stops there. Point a repeater into the block instead, or read its weak power with a repeater on the far side, back against the block.
Redstone torches flip the signal
A Redstone Torch stays lit until the block it is attached to is powered, and relights when that power stops. Each change takes 0.1 seconds, and that inversion makes the torch a NOT gate.
A lit torch strongly powers the block above it and powers dust and devices beside it, but never its own block. On a non-conductive block such as glass, a slab or a fence it can never switch off. Force a torch off eight times within 3 seconds and it burns out for a while.
The components that shape a signal
| Component | What it does | Timing |
|---|---|---|
| Redstone Repeater | Boosts any signal back to 15, one way only | 1 to 4 redstone ticks of delay |
| Redstone Comparator | Keeps the strength, compares or subtracts a side input, reads how full a container is | 1 redstone tick of delay |
| Observer | Fires a signal of 15 when the block in front changes | A pulse 1 redstone tick long |
One redstone tick is 0.1 seconds; the redstone tick calculator converts ticks to seconds and works out a repeater chain's delay. A repeater takes three Stone (not Cobblestone), two Redstone Torches and one Redstone Dust (the repeater recipe); comparators and observers need Nether Quartz. Each has its own guide: repeaters, comparators and observers.
The dust comes from Redstone Ore, found from Y=15 down to the world's bottom and commonest around Y=-59 (best Y level for every ore). An Iron Pickaxe or better gets 4 to 5 dust a block, up to 8 with Fortune III.
What redstone can switch
- Piston and Sticky Piston: extend while powered and push up to 12 blocks. A sticky piston pulls its block back when power stops.
- Doors, trapdoors and fence gates: open while powered. An Iron Door opens only with redstone.
- Redstone Lamp: light level 15 while powered, off 0.2 seconds after power ends.
- Dispenser and Dropper: fire once each time power switches on. Use a redstone clock to repeat.
- Copper Bulb: toggles with each new pulse and keeps its state unpowered.
- Hopper: power locks it, so it moves no items.
Your first circuit: a night light
You need a Daylight Detector (3 Glass, 3 Nether Quartz, 3 wooden slabs), a Redstone Lamp per light (a Glowstone block inside 4 Redstone Dust), dust and a Redstone Repeater. The quartz and Glowstone are found in the Nether.
- 1.Place the Daylight Detector under open sky. Shade keeps an inverted detector on in daylight.
- 2.Use it once to invert it, so it gives a signal as daylight fades.
- 3.Put a Redstone Repeater right after it, so every lamp gets full strength from the first signal.
- 4.Run dust straight into each Redstone Lamp, with another repeater after every 15 blocks.
The lamps switch on together at dusk, and also in rain or thunder, which dim the sky. A hidden piston door is the natural next build.
When a circuit misbehaves
- A device stays off: dust runs beside it instead of into it.
- The signal fades: the line passes 15 blocks without a repeater, or starts from a weak source.
- A repeater ignores the signal: it arrives at the side, not the back.
- A torch never turns off: it sits on a non-conductive block such as Glass.
- A piston fires unasked: something powers the space above it (quasi-connectivity).