I. Summary

    The n.a.d.s. is the N810 Audio Display System. It was originally designed as a replacement to the insufficient audio system in the car shown in Figure 1. The car's audio receiver supported only mp3 CDs, which, while convenient, lead to a large physical collection of mp3 CDs and disallow a true random sort of a music library larger than 600 MB. However, the receiver had an auxiliary input, which the n.a.d.s. connects to.

    Unfortunately, most existing portable mp3 players could not suit the needs of this project. In the same way that an mp3 CD limits to 600 MB, an iPod (at the time of this writing) will limit to 160 GB and a Zune will limit to 120 GB. The desired library, however, was over 200 GB of music. Moreover, an iPod does not make a software upgrade path very feasible; nor do other devices of that ilk. Instead, an open-source solution allowing easy modification was desired.

    Therefore, the requirements were formed:

  • Scalable library size
  • Open-source playback software
  • Mountable frontend
  • Easy-to-manipulate interface

Figure 1. 1996 BMW 318ti.

    The release of the Nokia N810 [1] in November 2007 in addition to a well-timed presentation by the Linux Users Group at Georgia Tech [2] presented a solution for the stated problem. The N810 has a micro-USB port which can be hooked up to a USB hard drive. Therefore, a USB hard drive could be used to store the massive music library, while the (now) open-source program Canola [3] could be used as a frontend. A screenshot of the Canola interface can be seen in Figure 2.

Figure 2. Canola playback interface (ugly green scheme).

    A power supply was built for the N810 and the USB hard drive, and integrated into the +12V auxiliary power system in the car. Then, album art was embedded in each of the mp3 files in the music library. After this, Canola had to be configured to read these album art files. Canola also had to be modified to work efficiently with large libraries, and to not automatically refresh the library on the disconnection of the USB hard drive. Several components of the N810 operating system (Maemo) had to also be modified for streamlined operation.

II. Project Map
III. Current Status

    At the current time, the n.a.d.s. is mostly implemented and being used on a regular basis for car trips longer than a few miles. The mounting system is not yet complete, but most of the software and hardware problems are sorted out. The power supply is rock solid and has never failed. However, a few problems remain:

IV. References

[1] - http://www.nokiausa.com/find-products/phones/nokia-n810
[2] - http://lugatgt.org/2008/02/13/the-nokia-internet-tablet/
[3] - http://openbossa.indt.org/canola/

   power supply
   n810 hacks
   canola modifications
   car mount

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