Hardware

Using a Dell DJ MP3 player for field playback of bird songs.

Rev A2, November, 2005

The Dell DJ 30 is a very compact and sleek unit that measures approximately 4 x 2.4 x 0.7 inches and weighs 6.4 ounces. I use it with an optional soft carrying case which increases the weight to 7.6 ounces. For output, I use a Radio Shack mini speaker-amplifier (catalog #277-1008C). The speaker-amp measures

3.5x 2.75 x 1.4 (base), 1.2 (top) inches and weighs 5.4 ounces when equipped with a rechargeable 9 volt battery (weight includes modifications). I use a 6’ cord with 1/8 inch miniplugs to connect the units.

Unlike some MP3 players that use four compass point buttons to navigate through the various on-screen menus, most operations with the DJ are done using the centrally located “scroll-select” dial. This slightly ribbed wheel can easily be rolled up and down using a thumb and pressed to activate the currently highlighted selection

The main menu can always be reached quickly from anywhere in the menu system by pressing the “home” button to the right of the scroll- select dial. From there I can get to any bird very quickly.

The power button on top of the unit must be depressed for 2 seconds to prevent accidental operation; a slide switch locks out buttons.

Complete information about controls and operation can be found in the DJ 30 user’s guide (see appendix).

The DJ supports selection of music tracks by Genre, Album, Artist and Playlists. See the implementation section on how I use these features.

The back of the speaker- amplifier is secured by a screw which I removed and replaced with a Velcro strap to facilitate easy field replacement of the battery.

I also added a push button for easy on/off control.

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