Nokia N97 – keyboard thoughts
July 13, 2009
Bismillah, alhamdulillah.
I asked myself why did I not like the Nokia N97 keyboard? The main thing having contemplated over it was the lack of tactile feedback when the buttons are pressed. But what exactly is tactile feedback?
Tactile feedback to me is the ability to tell that a key has been pressed without looking at the screen. The way we detect movement of keys is a combination of two primary feedback systems. The first are proprioceptors and the second are pressure sensors. Pressure sensors lie under the skin and are onion layered like structures which help us determine pressure. These are the primary receptor behind the sense of touch. Proprioceptors are receptors which are attached to joints and muscles, these send back information to the brain on the degree of angular movement of a joint, degree of stretching of muscles fibres and tension in ligaments.
The human hand has five fingers, one of which, the thumb, is positioned so that its movement is orthogonal to the natural movement of the other four fingers. So when we use a full size keyboard the thumb is effectively rendered with little function apart from pressing the space bar as the position of the hand when typing help is in consonance with the movement of the four fingers rather than the thumb.
The opposite happens to be the case when we use a thumboard if the phone is held by both hands the thumb is positioned in a way that allows for its easiest and most natural movement which is across the surface of the palm of the hand.
Though a statement of the obvious, it is worth stating, with normal keyboards we use our four fingers (fore, middle, ring and little finger) and with thumboards we use our thumbs.
Our four fingers primarily detect movement through proprioreception when typing hence movement of the key in and out of the surface of the keyboard aids the feeling of what makes a good keyboard. But the thumb when using a thumboard relies more on pressure detection rather than movement of at the thumb metacarpophalangeal joint (detected by proprioceptive receptors). An easy way to realise this is to try and detect your pulse with the tips of your fingers and then detect it with the middle of the pulp of your thumb – you will notice that the thumb is very much more sensitive. Hence a thumboard which enhances pressure detection of keys and allows from some deformation of the key when it is pressed will enhance the tactile feedback of the the keyboard.
Turning back to the Nokia 97 keyboard, the keys are flat and fixed in shape. This reduces the pressure the thumb when it is placed on the keys, hence reducing the tactile feedback, further the degree of movement of the keys into the keyboard are also limited reducing the proprioceptive feedback. Putting this all together an ideal thumboard should have rounded keys rather than flat keys, which deform slightly allowing the sensitive pressure receptors in the thumb to detect that they have been pressed and some degree of movement all together would enhance tactile feedback significantly.
And Allah knows best.
Entry Filed under: IT. .
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