Ars liveblog: http://embed.scribblelive.com/Embed/v5.aspx?Id=22452&ThemeId=8...

6ren · on March 2, 2011

> if you tap softly or hard, it changes the sound

How can a touch-screen detect velocity? There's no travel. (I ask because it would be cool if you can).

EDIT iPad has an accelerometer, so it can measure the force at which your finger strikes the display

WesleyJohnson · on March 2, 2011

They're saying it uses the accelerometer in the device itself to detect how hard you touch the screen?

tesseract · on March 2, 2011

The screen is rigidly attached to the rest of the device, so yes, it should be possible to use the accelerometer (F=ma) to measure a force applied to the screen.

culturestate · on March 2, 2011

They use the accelerometer.

dazmax · on March 2, 2011

I wonder if it has to be on your lap or some surface that has some give for the accelerometer to properly pick up how hard you tap.

culturestate · on March 2, 2011

I think for maximum accuracy (or at least, as accurate as you can be using this method - I can't wait to try it out), you're probably correct.