This is one thing I like about the design of the DataHand - there is no electrical contact to close. The keys have a magnet holding them onto the base, and when you press them you break the magnetic grip and push the key through an optical sensor.

There's no need to slam the keys until you hit a stop just to make sure they make contact. There's also not much chance you can push the key 'a bit' and have it not register, i.e. if you press it hard enough to move the key then they key moves past the sensor, otherwise it doesn't move at all.