Short answer
The four documented Logic pieces form a small signal path in Sandustry: Signal Sensor and Presence Sensor detect elements in a 4×4 area, Signal Linker wires a sender to a receiver, and Buffer forwards its input unchanged. The steps below stay within those documented behaviors so you can test a circuit without assuming extra rules.
What each component does
Signal Sensor
Signal Sensor emits a signal when its 4×4 area is full of elements. The official mechanics description specifies that any combination of elements in the sensor box triggers a constant signal. In practice, fill the complete 4×4 area when you want to test this condition.
Presence Sensor
Presence Sensor emits a signal while at least one element is inside its 4×4 area. Any amount of any element inside the sensor box triggers a constant signal. In practice, place one or more elements in the area when you want to test this condition.
Signal Linker
With Signal Linker, press the sending and receiving devices, then drag the wire from the sending device to the receiving device. When the sending device transmits an on signal, the wire is green; otherwise, it is red.
Buffer
Buffer forwards its input unchanged. Use Signal Linker to extend a signal through Buffer when the path needs an intermediate device.
Build a test signal path
- Choose one sensor and prepare its 4×4 area. For Signal Sensor, make the area full of elements; for Presence Sensor, place at least one element inside it.
- Use Signal Linker to connect the sending device to a receiving device. Start the wire at the sender and drag it to the receiver.
- If you need to route the signal through Buffer, connect the sender to Buffer, then continue the signal path from Buffer with Signal Linker.
- Read the wire color: green means the sending device is transmitting
on; red means it is not. - Change the elements in the sensor area—fill or clear the 4×4 area for Signal Sensor, or add/remove the element for Presence Sensor—and observe the documented signal condition again.
The key distinction between the sensors
The sensors use different conditions:
- Signal Sensor: its 4×4 area is full of elements; the official page describes a constant signal when the box is full, regardless of the combination of elements.
- Presence Sensor: at least one element is inside its 4×4 area; the official page describes a constant signal while any amount of any element is present.
Both pages describe the contents of the sensor box as the input condition. The receiving device determines what it does with the signal, so use that device’s own documentation for its behavior.
Troubleshooting with the documented behavior
- The sensor does not emit the expected signal: check the exact area condition. Signal Sensor needs its entire 4×4 area full; Presence Sensor needs at least one element inside its 4×4 area.
- The wire is not connected: redraw the Signal Linker wire from the sending device to the receiving device.
- The wire color is unexpected: green means the sender is transmitting
on; red means it is not. Use this color as the visible signal check. - The path uses a Buffer: remember that Buffer forwards its input unchanged. Check the Signal Linker connection into and out of the Buffer.
- You need to extend the path: place Buffer in the route and use Signal Linker to carry the signal through it.
Scope of this guide
These four official pages document element detection, sender-to-receiver wiring, the wire’s green/red state, and unchanged forwarding through Buffer. They do not establish additional sensor readings or control rules; follow the documentation for any other Logic device connected to the receiving end.