MP3 car stereo

Terence Sin (zippy@myna.com)
Sun, 17 Jan 1999 14:38:07 +0000


http://www.empeg.com/tech.html

The empeg-car is an in-car digital music player, allowing you to have up
to 7,000 singles (or over 500 albums) instantly accessible in
CD-quality, in your dashboard. No boxes in the boot. You can categorise
tunes with the supplied PC-link software, and play the music that you
like, whenever you want it.

The unit uses a Digital/Intel StrongARM processor running at 220Mhz,
which provides enough power for MP3 decoding, plus plenty of spare
capacity to deal with future standards as they arrive. It’s got 8Mb of
memory, plus flash ROM to store the bootstrap. Up to two 2.5" laptop
drives can be fitted to the shock-mounted cradle inside the unit: with
current drive sizes, this gives up to 28Gb of storage - although the
PSU and hardware is capable of handling 4 drives (56Gb!) there isn't
enough vertical room in the box for 4 drives. Maybe later :-)

On the audio side, a custom in-car DSP deals with the DAC and provides
digital loudness, bass, treble, balance and fader for the four outputs.
It also gives a separate 5-band equaliser for each of the four channels.

The decoder software can cope with MPEG 1, layer 3 compression as well
as the higher quality (and less compressed) MPEG 2 formats. We plan to
expand this as standards shift and, as it’s all done in software,
there’s no getting left behind with out of date hardware.

On the front of the unit there’s a graphic vacuum-fluorescent display,
giving a sharp, clear, high-contrast information readout. Apart from
showing you what tracks are playing and letting you browse the menus,
you can turn on visualisation mode using Orogenic’s Prolux to give you
spectrum analysers and plasmas that move with the music.

Also on the front is both an IrDA transceiver and a consumer-IR
receiver, which deals with both the IR remote and also with talking to
things like palmtop computers. Currently, there’s no software to talk
to devices like the PalmPilot, but we hope some madman will write some
and we’ll help where we can.

Round the back live the serial (230,400bps max), USB (12Mbit) and home
power-in jacks, plus the docking connector for the in-car mount.

Why Linux? Well, it provides a good support environment for the unit’s
software, and is solid and reliable. We also like it a lot, and worship
Linus on a daily basis at our own personal shrine. Not that we’re
obsessed, or anything...

People have asked about making the unit more open. At the start, we
don't have the manpower to offer this sort of thing, but it is planned
to release a setup which will allow logins, and be configured with gas
and gcc for users to develop their own software on the unit. However,
there will be no support for this - you have to be serious about it,
and happy with Linux and software development in general for this to
appeal to you. In the worst case, you can always reinstall the default
software - the boot code is protected, so you shouldn’t end up with a
dead unit.

The unit's UI is written in Python, allowing Python-esque users to add
features and giving great flexibility in the way the unit works.