Keyboard hipsterism just took another step forward, as Hall-effect keyboards are making a return to the market. The resurgence of the nearly-forgotten keyboard technology is happening thanks to a Massdrop group-buy (login required) run by a man named José Soltren, better known as XMIT. The keyboard is likewise called the XMIT Hall Effect Keyboard. There have apparently been a few production issues along the way, but the first keyboards have now made their way into the hands of lucky buyers.
If you're wondering what the heck a Hall-effect keyboard is, well, let me tell you. As a recap, when you press a key on a typical computer keyboard, you compress a rubber dome with a metal contact on the bottom, completing a circuit and registering a key. Mechanical keyboards use a spring mechanism instead of a rubber dome to to reset the key, but they still rely on two metal contacts touching to register a keypress.
Hall-effect keys are frictionless in operation. That means no physical contact is required between the key itself and the switch element. They achieve this by making use of the Hall effect, a shift in a wire's voltage caused by a magnet affecting it. Essentially, the voltage is measured across a wire at a specific point, and when you depress the key, the magnet changes the value, registering a keystroke. This technology is used often in simulator gear like joysticks and steering wheels.
Given that there's no physical contact, there's no "bouncing" effect as happens with rubber-dome and mechanical keyboards. That means the keyboard circuitry itself can be simpler, since it doesn't have to account for the repeated keypresses caused by key bounce. It also means that the switches last longer, and that they can feel smoother. All-in-all, fans of the technology say it offers a superior typing experience versus mechanical keyswitches, and even versus other exotic keyswitch technologies like Topre's electrostatic capacitive switches.
Hall-effect keyboard switches were once popular on high-end computer keyboards in the late 1970s and early 1980s, particularly for military and industrial use. However, the high cost of manufacturing led them to be phased out in favor of cheaply-manufactured and easily-replaced dome keyboards. The switches in the XMIT keyboard are a new design that's compatible with Cherry MX keycaps. It's also apparently easy to manufacture, seeing as the keyboards went for as little as $100 in the Massdrop.
The XMIT Hall-Effect keyboard arrived in six variations. There were 61-key, 87-key, and 104-key versions, and each was available with 35g or 50g actuation force. The 50g models are similar to Cherry MX Red keyswitches in terms of force required, while the 35g switches are extremely light. Fancy switches aside, the XMIT keyboard also comes with PBT/POM double-shot keycaps, water-resistant epoxy coating, and per-key-configurable RGB LED lighting. It does appear to lack media keys, though.
Unfortunately, XMIT's group buy is over, so it's too late to get in on this production run. Fortunately, he says he's already identified a list of "50 little changes" he'd like to make to the current design, and that he plans to produce more. If you're interested in picking up one of these keyboards, keep an eye out. Thanks to Tom's Hardware for the tip.