Pictures of the embedded MP3 player's hardware 

First, the actual unit: it's long and thin, as the space it fits into is also long and thin! The lower bit is the actual computer box, which houses the embedded PC, hard disk, and I/O connectors. The louvres at the front are for the cooling air to exit: the ones in the top are directly above the CPU fan. The air blows from the back of the unit (where a 50mm Pentium heatsink fan is mounted), past the PSU and through a hole into the main computer case. The connector to the right of the fan is the Neutrik Speakon socket, where the power goes in. Also at the front is the 25-way D connector, which houses keypad scan, display drive & power, COM2 serial I/O (for the mobile phone) and 10-base-T ethernet: below this are the two phono sockets for audio out. To remove the unit from the car, I just have to remove the 25-way D, the audio and the power - much neater than connections for everything individually.

Next, some pictures of the inside of the case. The wiring isn't very neat (a slight understatement...) but the extra power wire lets me hook it up to a real PSU indoors if required. The ribbon cable is all over the place as the SBC uses IDC plugs for practically all its I/O (serial, video, audio, parallel...) - the audio stuff gets straight into sheilded cable within a few millimeters though, in an effort to preserve audio quality.

The inside of the PSU part: on the left is the PIC16LC84 board, with ribbon cable going off to the other end of the case where it goes into the 25-way D connector (which connects to the keypad) and to COM1. The component bolted to the case is the VN05 solid-state switch. The board on the right is the switch-mode PSU, and the gunk it's all covered in is hot melt glue to help prevent components from wobbling about and breaking tracks. As you can see, the ait blows in from the fan, over the PSU and through the hole by the PIC board into the main box.

The hard disk is mounted in a little U-shaped bracket hanging from the lid of the box. As you can see, the disk is semi-shock mounted using gromits in the holes in the cradle, between the cradle and the hard disk, and between the cradle and the plastic screw-head.The white bit is some fanfold paper pretending to be a gromit, because I lost one!


Return to main page