Hall Effect and Optical Switches

Hall effect switches use a magnet in the moving stem and a sensor on the board that detects the magnet's position. Because the sensor reads how far the magnet has traveled rather than a single on or off contact, the board can know the exact depth of the press at every moment. That opens the door to adjustable actuation, where you set how far down a key must go before it registers, and to features that respond to partial presses.

Optical switches register presses by interrupting a beam of light. When the stem moves down, it either blocks or unblocks a light path, and the board reads that change as a keypress. Removing the metal contact can reduce certain forms of wear at the contact point and allows for very fast registration, which is why optical switches are often marketed toward gaming.

The headline advantage of the hall effect approach is adjustability and analog style input. Being able to tune actuation depth per key, or to have the game read a key like a gradual trigger rather than a simple button, is genuinely useful for some gamers and is difficult to replicate with contact switches. These features are the main reason people seek these switches out.

There are trade offs to weigh. Contactless switches typically require a board specifically built to support them, so they are not a drop in replacement on an ordinary hot-swap board, and the ecosystem of compatible parts is narrower. For pure typing feel, plenty of people are perfectly happy with traditional mechanical switches. Consider hall effect or optical switches if adjustable actuation or analog input genuinely appeals to you, and stick with conventional switches if those features are not a priority.