Samsung Galaxy Stylus

The S-Pen

Underneath that gorgeous screen there are two main boards; the sensor and the control board. The sensor board has coils arranged in the x and y axis (sound familiar?) and the control board uses alternating current to switch select coils in the sensor board on and off rapidly, this excites the little coils and they generate a magnetic field.

Each time the S-pen passes through these magnetic fields it picks up and stores energy in its resonant circuit. This energy is then used to return a magnetic signal back to the control board (number 3 in the Galaxy Note teardown picture from Samsung Tomorrow) in the Galaxy Note. Using this method, the S-pen can transmit a whole host of information such as angle, pressure and co-ordinates.

Now I hear you asking “why is that so much better than a usual stylus?!” or you may be saying “urgh, using a stylus is so 90′s!”

Why is the S-Pen better than a usual stylus?

Well lets head back to the fact that with the S-pen you can have up to 256 levels of pressure and it’s accurate to 0.5mm which is all down to the snazzy technology inside it., the S-pen also doesn’t need to be in contact with the screen for the Galaxy Note to register its position (it can be free to hover a few mm above the screen). Other styluses such as capacitive are just that….capacitive, this means there will be some kind of conductive material at the tip of the stylus.

A capacitive screen works by detecting changes in capacitance of the screen, these slight changes are caused by distortion in the screens electrostatic field and in turn these distortions are caused by touching it with your finger (as we humans are electrically conductive!). Basically a capacitive stylus just mimics this effect, but with a smaller ‘point’ than your finger. Another type of screen that can use a stylus is the resistive touchscreen, now this doesn’t require a special capacitive stylus, any pointy thing will do!

A resistive touch screen is composed of two layers with an air gap or microdots between, on each layer there are horizontal and vertical lines, when these lines are pushed together they register the coordinates of the touch. In its own nature resistive technology isn’t very accurate and often you need to push that little bit harder to register a touch in the first place.

As you can see technology is a wonderful thing, and even the most largest sophisticated technology may be sitting in your pocket already!

If you’re interested in the technology in the Galaxy Note’s S-Pen and want more detail, check out Wacom’sexplanation of the technology and Samsung Tomorrow’s Galaxy Note teardown.