Mon 25 August 2014

by Jorge Herrera and Hyung Suk Kim

What is it?

Ping-Pong is an iOS app that allows to measure the distance between 2 or more iOS devices using pitched sound. When three or more devices are present, then Ping-Pong can also estimate the 3D position of the devices.

If you are interested in more details, check our ASA paper.


Well, the initial motivation was SLOrk and MoPho, where some pieces make use of the locations of devices/players during the performance. We wanted to come up with a musical way to getting the locations, possibly make a musical piece in doing so.

Although that's our initial inspiration, we think this opens a door to explore new ways of interaction in a physical space. Maybe gaming or other casual social interactions can benefit from this kind of system.

From a more philosophical point of view, we feel that by doing this, we can help bring the virtual life back into a physical one.

See it in action!

This is an early demo, showing pairwise distance measurements alone (no geometry calculation). The app interface is in early development stage.

In this second video, you can see the whole system in action. You see 4 mobile devices running the PingPong app. They are all connected to the same wireless network. They sequentially play sounds back and forth to measure the distance between device pairs. This process is visualized in realtime in the lower right corner.

NIME 2014 presentation

A Visualization

This visualization show a set of distance measurements between four devices. For each device initiating the measurement, the actual distance to the other three devices is shown as a light-blue arc. Five measurements to each of the other three devices are shown in orange arcs. It should be noted that device 1 is an iPad 3rd generation, while the other devices are 2 iPod Touches (devices 2 and 4) and an iPhone (device 3). As can be seen, measurement involving an iPad are less precise. We believe it has to do with the larger size of the device (larger distance between speaker and microphone).