The Laser Detector is an item found at Link's Logic, which is located in the Tropics Biome that is only accessible via the Ferry. This can only be used with a Laser as it requires a laser being emitted into the detector to output a signal. It will only emit a signal when it detects a Laser going to the detector. This is useful for making scanning machines as it can help detect specific items as there is no signal at all when the laser is blocked. It is more effective to use a Signal Inverter as it will be outputting a signal when the Laser is being blocked, therefore it would make it easier to make circuits and machines.