Saturday, December 19, 2009

Inside the Trackpad: a BlackBerry Science Lesson

You might have noticed a different navigation tool on recent BlackBerry® smartphones like the BlackBerry® Curve™ 8520 smartphone and BlackBerry® Bold™ 9700 smartphone. Inside BlackBerry wanted to find out how the trackpad worked, so we went and sat down with David (Vice President of Handheld Products) and Derek (Electronics Designer) for a quick lesson.
In the most basic terms you might have heard the trackpad described as an optical mouse. 'Think of your standard red-light mouse except your finger is the desk, and you're moving the desk,' explains Derek. 'So the tiny little imperfections of a desk that your mouse picks up on to navigate, it's now replacing that with your thumb.'
To explain how this navigation process works, David tells me to picture the trackpad as 'an infared video camera turned upside down.' Derek agrees and pulls up a screen shot showing a very pixelated grey-scale blob that is actually a finger (see diagram after the jump). He continues, 'you have a very low resolution, very fast frame-rate camera: black and white, grey scale.' What the camera sees and registers are the gradations in your finger.

As you move your thumb across the trackpad, a special algorithm happens inside which spits out 'you moved left 3 spaces' or as Derek a little more technically put it 'it spits out: delta x, delta y.' Or, in diagram form, this is what is happening:
the trackpad is really just snapping images and doesn't require any kind of
conductivity like a touchscreen, it means you don't necessarily have to use
your thumb or fingers. You can actually navigate around your screen using
anything that has a slightly rough surface. Naturally, David and I put this to
the test. We used a note book and a pen, both of which worked fine (not as good
as a thumb, but in a pinch it would suffice).

probably enough BlackBerry science for one day. Tune in next week for our
history lesson on the trackpad when David explains the evolution of the
navigation technology for BlackBerry smartphones.

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