XTouch, an SDK created by a group at the University of Toronto’s Mobile Applications Lab and funded by JOLT, turns any surface into a touch-sensitive controller for iOS apps with no additional hardware. Since XTouch uses acoustics and vibrations to recognize taps on a surrounding surface, the only requirement is that your iPhone or iPad is placed on the same surface you want to use as a touchpad. An SDK is coming soon that will allow developers to think up many interesting implementations, but for now the company has released two apps that show off what XTouch is capable of.

One of the apps, Voodoo Tap Frogs, was recently recognized by Apple as a best new iPhone/iPad game in the App Store, but has yet to get any mainstream attention. It has up to four players sit around a table (or any flat surface), each tapping the table in front of them to control an onscreen character. It’s featured in the video above and is debuting alongside another other app just released by XTouch, Magic Xylophone.

Co-founder Parham Aarabi explained to us how the tech works:

“The XTouch technology works with any existing device that has at least one microphone.  No additional hardware or sensors are needed.  It ‘understands’ the unique acoustic signatures generated when you tap at different locations on a table, and after a quick calibration phase, where ever you tap, the sound is classified and based on that we come up with a location estimate.

Essentially, we have way to distinguish the subtle difference between different tap sounds on a surface in order to find out where someone is tapping/touching.”

By using a surrounding surface instead of blocking the display with your hands, the platform opens up a lot of opportunities for apps and games to implement collaboration features by allowing input from more than one user. It could also come in handy for a lot of applications where tapping a surrounding surface may be more convenient, such as tapping your nightstand to silence your phone’s alarm clock or a countertop to interact with a cooking app or answer a call when your hands are dirty.

The SDK is arriving sometime in Q2 for developers, but you can check out the technology in the two apps released by XTouch.