Quick Answer
Sandustry logic uses sending devices, receiving devices, and Signal Linker wires. Drag a wire from a sender to a receiver. The official wiki says a transmitting On signal makes the wire green, while an Off signal makes it red. Use a Signal Switch for a manually toggled constant state, a Signal Button for a brief manual On pulse, or one of the three documented 4×4 sensors for material-driven input. AND turns On only when all its inputs are On; OR turns On when any input is On. Treat NOT as a special one-input device: its official page requires exactly one input and says multiple inputs produce Off.
Know the Confirmed Logic Set
The official wiki’s main page currently places these names in its Logic collection: Signal Linker, Signal Switch, Signal Button, Signal Sensor, Pulse Sensor, Presence Sensor, Buffer, Toggle (T-FlipFlop), Signal Lamp, AND Gate, OR Gate, NOT Gate, NAND Gate, NOR Gate, XOR Gate, XNOR Gate, and Repeater. This list confirms that the components are categorized as Logic; it does not, by itself, document every component’s behavior.
This guide explains only the components whose dedicated official pages are included in the source set below. Buffer timing, Toggle state rules, Repeater behavior, Signal Lamp behavior, and the truth rules of NAND, NOR, XOR, and XNOR are therefore pending confirmation here.
| Component | Officially documented behavior | Best-supported use |
|---|---|---|
| Signal Linker | Drag from a sending device to a receiving device; green is On, red is Off | Create and inspect a connection |
| Signal Switch | Manually toggles a constant On or Off signal | Stable manual test input |
| Signal Button | Sends a brief On signal when manually activated | Manual pulse input |
| Signal Sensor | Constant signal while its 4×4 area is full of elements | Full-area state detection |
| Pulse Sensor | One brief signal when its 4×4 area becomes full; resets after it is no longer full | One event per fill cycle |
| Presence Sensor | Constant signal while any element is in its 4×4 area | Presence detection |
| AND Gate | On only if all inputs are On; accepts multiple linkers | Require several conditions |
| OR Gate | On if any input is On; accepts multiple linkers | Accept any of several conditions |
| NOT Gate | Inverts exactly one input; more than one input produces Off | Invert one documented condition |
Wire a Signal in the Correct Direction
Select the Signal Linker, start at a sending device, and drag to a receiving device. Direction matters because the official instructions distinguish sender from receiver. Once linked, read the wire as a live state indicator: green means the sender is transmitting On, and red means it is not.
A sensible first test is a Signal Switch connected directly to a known receiver in the current game build. Click the switch and watch whether the wire changes between green and red. This is a suggested diagnostic derived from the documented constant output and wire colors. It does not establish port counts, maximum wiring distance, signal delay, power use, or the behavior of the receiver.
Use the Signal Button when the input should be brief rather than persistent. Its official page describes one short On signal after manual activation. Do not describe the pulse with a number of ticks or seconds unless an official page supplies that value. Observe the wire while activating it, but do not claim an exact duration.
Choose the Right 4×4 Sensor
All three documented sensors inspect a 4×4 area, but they answer different questions. Signal Sensor asks whether that area is full of any combination of elements and maintains a signal while that condition holds. Pulse Sensor also reacts when the area is full, but sends one brief signal and does not become ready for another fill event until the area is no longer full. Presence Sensor has the lowest stated threshold: any amount of any element inside its 4×4 area creates a constant signal.
Choose by desired signal shape, not by the sensor’s name alone. For a state that should remain On while an area stays full, use Signal Sensor. For one action per transition to full, use Pulse Sensor and make sure the area later becomes not full so it can reset. For a state that should remain On whenever anything is detected, use Presence Sensor. The official pages do not distinguish material types, so this guide does not claim filtering by Sand, Water, or another element.
Combine Inputs with AND, OR, and NOT
AND and OR accept input from multiple Signal Linkers. AND produces On only when every input is On. OR produces On when at least one input is On. A safe learning circuit uses two manual Signal Switches feeding one gate: toggle each switch separately, observe the two input wires, and then observe the gate’s outgoing state. This is a suggested way to verify the published rule without assuming a hidden timing model.
NOT needs stricter handling. The official page says it outputs the inverse of a single input and “requires exactly 1 input.” It also explicitly says that although multiple linkers can be attached, more than one input makes the output Off. Do not generalize this device as a textbook NOT implementation that will simply ignore extra wires. If a NOT circuit stays Off, count its incoming connections before investigating anything else.
Build a First Reliable Circuit
Start with the smallest path. The following sequence is a recommended debugging workflow inferred from the official component descriptions:
- Link one Signal Switch directly to a confirmed receiver and verify red/green state changes.
- Replace the Switch with a Signal Button only when you specifically need a brief manual pulse.
- Test one sensor directly before adding a gate; deliberately change only the contents of its 4×4 area.
- Add an AND or OR gate after both inputs behave correctly on their own.
- Use NOT with exactly one incoming linker and inspect for accidental extra connections.
- Change one component or wire at a time, then repeat the same input condition.
This order separates sender, wire, gate, and receiver problems. It is not an official factory blueprint, and it makes no promise about transmission range, tick delay, ports, energy, unlock price, or compatibility with a particular door or production machine.
Diagnose a Signal That Does Not Work
First inspect the wire color. A red wire indicates an Off sender, so return to the Switch, Button, or sensor condition. For a Signal Sensor, confirm the entire 4×4 area is full; for a Presence Sensor, confirm at least one element is inside; for a Pulse Sensor, remember that it sends only one brief signal per full state and resets only after becoming not full. These checks follow the official descriptions.
If the incoming wires are green but a gate’s output is unexpected, compare the exact inputs with the gate rule. AND needs all On; OR needs any On. NOT needs exactly one connection, and multiple inputs force the documented Off output. If the logic output looks correct but the final device does nothing, verify that the final link was dragged from sender to receiver and consult the receiving device’s current official or in-game instructions. Do not invent a door truth table to fill that documentation gap.
Keep Unsupported Details Out of the Design
No source used here establishes maximum link distance, per-tick latency, port limits, energy draw, unlock costs, or version-specific placement rules. The selected pages also do not document Buffer, Toggle, Repeater, Signal Lamp, NAND, NOR, XOR, or XNOR behavior. Those details remain pending confirmation rather than being completed from conventional electronics terminology.
Label your own observation with the game version and treat it as a test result. Use visible wires, test one state at a time, and preserve a direct manual Switch path while diagnosing. This advice is an inference from observable official states, not a claim about internal timing.
Sources
- Sandustry Official Wiki — Logic component list
- Signal Linker, Signal Switch, and Signal Button
- Signal Sensor, Pulse Sensor, and Presence Sensor
- AND Gate, OR Gate, and NOT Gate
This independent guide is not affiliated with Lantto Games, Hooded Horse, or the Sandustry Official Wiki.