Maker

VoIPing the iPod Touch

How makers gave you the feature that Apple held back. By Erica Sadun

It’s a maker’s dream: turn your homebrew ideas into a concrete reality and then ship that product. This dream came true for iPod hackers Dr. Marián Képesi, “Eok,” and Samuel Vinson. They designed, built, and shipped an iPod touch microphone and developed VoIP (voice over internet protocol) software to place phone calls using that mic.

Last November, Képesi was poking around on his iPod Touch. A postdoc at Austria’s Graz University of Technology, he had previously worked with third-generation iPods and was interested in the new Touch line.

During his explorations, he discovered an important fact about the iPod Touch’s bottom connector port: its line-in audio was active. Live pins meant that the iPod Touch could connect to an external audio source. It was compatible with recording or,

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better yet, with VoIP for talking over the internet. VoIP compatibility was a long-standing goal of the iPhone and iPod Touch hacker community.

Képesi modded an old iPod docking cable, connecting the line-in pins to live audio, and recorded his first sample. The sound level was very low but the signal was live. Although Apple had shipped the iPod Touch as a “play only” device, Képesi had uncovered its ability to record.

He announced his discovery on the iPod Touch fan forums, and set to work adding an amplifier and boosting the audio-in quality. It took some searching but he finally found a small microphone that would fit inside a standard iPod dock connector.

Képesi then put together his parts list and posted the circuit details so anyone could build the open source, dockable microphone. Together, the parts

Photograph by Marián Képesi