Wooting, a start-up that is currently running an already-funded Kickstarter, is looking to produce a keyboard with analog inputs. This is not exactly an entirely-new concept. Ben Heck created one back in 2012 by modifying the WASD cluster to include Hall Effect sensors, which were attached to the guts of an Xbox 360 controller to signal thumbstick offsets. The further you press the key, the more intense of an input would be sent to the PC.
The Wooting One, which, again, is a Kickstarter campaign, does it a bit more… professionally. The keyboard uses the “Flaretech” switch, which I've never heard of before now, from Taiwanese manufacturer Adomax. Unlike Ben Heck's Hall Effect sensors, this one measures offset with light sensing. This raises a petty, pedantic argument about whether it's technically a mechanical keyboard, since the activation isn't performed by a direct, mechanical process, but users typically equate “mechanical keyboard” with its quality and feel, which could be achieved with non-mechanical processes. Semantics aside, the light-sensing mechanism allows precise measurement of how far down the key is. From there, it's just a matter of mapping that distance to an input.
This is where the Wooting One looks quite interesting. The firmware and driver will communicate under XInput and apparently other Gamepad APIs, functioning under most games that allow simultaneous gamepad + keyboard input for a single player. They are also expecting to create an open-source system, with an API, that allows games to access the analog input of apparently all keys on the board. This is interesting, because XInput has fairly restrictive limitations of about six axises of analog input (although the two axises corresponding to the triggers are lower precision and, with the Xbox One controller, joined into a single axis). A new API can circumvent all of this for gaming going forward, and it will be required for analog keyboards to get off the ground. It's not a difficult task itself, as there is quite a bit of bandwidth in external IO connections these days, but getting and entire industry's worth of vendors to agree could be a task (unless you're, like, Microsoft). Hopefully it's open, with a permissive license, and a few, big-name engine vendors add support to push it forward.
And, let's be honest — XInput is limiting. A new API could be good for obscure gamepads, too.
Outside of analog gaming, they are also milking this “know how far down the key is” feature as much as they can. For instance, they are also allowing users to choose the activation distance in digital mode. Users can set their balance between rejecting partial presses and speed of input based on their ability to touch type.
It's a European Kickstarter, and the lowest backer tier that includes the keyboard ships in November and is worth 100 Euro, ~$115 USD. which apparently includes tax and shipping for North America and Europe. That doesn't correlate to a retail price, if the product even gets off the ground, but it's a data point however reliable. Tax-in and free shipping sounds a bit… sketchy for a crowdfunding campaign… but that could just be a sign that they're more affiliated with an existing company (and its supply chain) than they're letting on, rather than business naivety.