report depicts the progress made on the mp3 car player since the first update
(January 22nd, 2001). As mentioned in the first report, the mp3
player is intended to replace conventional car stereos by playing compressed
music stored digitally on a hard drive. At this time, we manage to get all the
hardware that are required for the project, selected and obtained power supply
(model ACE-865V) which accepts 8~16VDC input from
the battery of the car and convert it to a stable source to the computer.
Details of Parts
A 100 MHz Intel Pentium motherboard is used for this project.
We are making use of a 64MB of RAM.
· Hard Drive
The size of the hard drive is 1.2gigabyte. The operating system takes 75megabytes. Each gigabyte of disk will allow us to store about 25 CDs.
· Sound Card
The sound card being used is Sound Blaster () from 3Com.
After a thorough examination of the options available for us, we’ve decided to use the ACE-865V power converter from arise computer. This model has the capacity of 8-16V input voltages, which is a reasonable range for the power obtained from the car battery. The input is then converted to a stable DC power of +-5V and +-12V and is fed to the computer. The built-in over voltage protection circuit will shut down the outputs to prevent damaging external circuits. The trip point of crowbar circuit is around 5.7V to 7.0V. The power supply will go into hiccup mode against short circuit or over load conditions, and will auto recovery while faulty conditions are removed. This will avoid serious problems that may occur when power is simply shut off.
The physical dimensions of the power supply is shown below:
All dimensions are in mm.
1. To save as much space as possible and use it for extra mp3 files.
2. In the long run, it might be nice to burn the operating system and software to a ROM chip so that we can have truly embedded linux stereo system.
software that drives the stereo is written in Perl. The software will
automatically run whenever the car is on and will use the keypad as an
interface and allow the user to browse and play all of the songs stored on the
hard drive. We use Mpg123 decoding software to output sound through the sound
card to the car stereo system. The interface reads in mp3 file names from a
default directory and displays them in a usable fashion. A display (GLK24064
from METRIX ORBITAL) is used to display the song names and album. Perl code is
written that monitors a line on the serial port and performs a system shutdown
when the line goes low.
Here is the proposed date for the completion of each task:
January 15th, 2001 All hardware parts really.
January 22nd, 2001 Progress report 1, Linux OS, and mpg123 software really
February 19th, 2001 Progress report 2, interface, and display screen really
March 17th, 2001 Alpha version of the desgin, Poster presentation
March 26th, 2001 Networks interface really and revision of all different tasks.
2001 Final Design, Prototype, and final report
All the parts have been made ready for the project. The parts are provided by the group members or ordered from electronics suppliers. Here are the parts:
The Linux operating system has been installed in the hardware. The size of the OS has been reduced to 70 MB.
The mp3 decoder, Mpg123, is a real time MPEG Audio Player for Layer 1,2 and Layer3. It has been tested working fine on our Intel 100 MHz machine with Linux OS.
· Power Supply
ACE-865V power converter is used for the purpose of this project. It accepts 8-16V input voltages and provides the motherboard with a stable +-5V and +-12V.
· Display Screen and Interface
The screen displays songs and albums. This is achieved by coding in Perl.
The following tasks must be completed before the final report will be completed: