Explaining Hall-effect, TMR, and other new types of "mechanical" switches

Contactless keyboard switches replace the metal-leaf contact of traditional mechanical switches with optical, magnetic (Hall-effect/TMR), or capacitive sensing so a keystroke is detected without physical contact between conductive leaves. Traditional switches close a circuit when two metal leaves touch, which creates wear and oxidation over long use. Optical designs use an IR emitter and sensor on the PCB with the stem acting as a shutter; magnetic designs use changes in a field to register actuation. Contactless modules require specific PCBs, are often packaged in nonstandard hot‑swap layouts, and typically cost more than conventional mechanical boards.

The practical benefits are longer resistance to oxidation, programmable actuation points, analog sensing and dual-input programming, and lower debounce requirements that vendors pitch as faster for gaming. Independent testing shows adjustable actuation settings often differ by fractions of a millimeter from software values, and overall latency depends on travel distance, actuation depth, and polling rate as much as sensing method. Some modern mechanical switches (e.g., MX2A-series) already reach 100 million keystrokes, and smoothness still depends on stem, spring, and lubrication, so contactless offerings mainly matter to enthusiasts and competitive gamers seeking ultra-low latency or analog control rather than average typists.