Nuts & Volts - February 2007

iNterface Your iPod

With all the aftermarket products available for the iPod these days, it makes you wonder if you can’t hack into the iPod yourself and build your own iPod gizmos. Yes you can! With the dock connector, the iPod can be charged, connected to a PC, connected to a stereo, or connected to a serial device and controlled via the Apple Accessory Protocol. Here is a quick overview of the docking connector and ways to utilize it.

by TJ Byers

Overview

In a nutshell, the Apple iPod is a personal MP3 player, about the size of a deck of cards, that is capable of storing thousands of tunes on its internal hard drive. It connects to Apple Macintosh computers equipped with a FireWire interface (all modern Macs) and syncs with Apple’s iTunes 2 (free) MP3 Player/Encoder/Organizer application.

However, the iPod also doubles as a portable hard disk drive that can be used for traditional data storage. It can even be used as

FIGURE 2

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February 2007

a boot volume. The interface types include FireWire, USB, TTL serial, audio, and video ports.

Docking Connector

The dock connector was introduced with the third generation iPods. The connector is proprietary (Figure 1) and manufactured for Apple by JAE (Japan Aviation Electronics). Until recently, you had to contact Apple, sign a Non-Disclosure Agreement and jump through hoops to obtain the mating connectors for the iPod. Fortunately, you can now find them from the following suppliers for about $2 each.

• Ridax — (646) 257-2080, http:// home.swipnet.se/ridax/connector.htm

• Spark Fun — www.sparkfun.com/ commerce/ product_info.php?prod ucts_id=633

FIGURE 1

FireWire

FireWire is the trademarked name of Apple Computer for the IEEE-1394 personal computer — and digital audio/digital video — serial bus interface. Virtually all modern digital camcorders have included this connection since 1995, as well as many portable computers, including all Apple, Dell, and Sony laptops (where it is known as i.Link).

The iPod uses a six-pin connector for the FireWire link (Figure 2). Pins 1 and 2 are used to charge the iPod’s internal battery via a 12-volt source. The data is transferred via two twisted pairs using CAT- 5 cable or any of several ready-made Fire Wire cables. Typically, you load the music or video file into the computer, then transfer it to the iPod using the Fire Wire connector at data rates of 100, 200, or 400 Mbps, depending on the particular model, using Apple’s software. This doesn’t prevent you from using the FireWire port with other devices — like video editors — using their software.