iPhone Touch Screen Beats Droid, Nexus One

Moto Development Group (no connection to Motorola) tested four devices: the iPhone, the HTC Droid Eris, the Motorola Droid and Google's Nexus One. Do-it-yourselfers can perform a similar test with any basic drawing program and a steady hand and drawing a few straight lines very slowly on the screen.

"On inferior touch screens, it's basically impossible to draw straight lines," according to the report on Moto's Web site. "Instead, the lines look jagged or zig zag, no matter how slowly you go, because the sensor size is too big, the touch-sampling rate is too low, and/or the algorithms that convert gestures into images are too nonlinear to faithfully represent user inputs." However, while the iPhone was the overall winner for accuracy, the Nexus One had superior edge performance -- the ability for the device to sense the user's finger at the edge of the screen.

Clearly, all touch-screen devices are not made equal. The success of Apple's iPhone has led to an explosion of similar devices. But not all of them have incorporated touch-screen sensors with high signal-to-noise ratios (SNR). High-quality sensors as well as substrate materials are essential for high SNR; manufacturers skimping on materials will experience poor performance.

In addition, the Moto report suggests that manufacturers not rush development of algorithms and to closely integrate touch-screen hardware, software and user interaction development.