Main page.


This page deals with my final year MScEE project: a self tracking webcam. This work was done for Staffordshire University (UK). The aim of this project is to build an endembed system pluged on a computer with only two wires ( two USB cables) able to make a camera self turn to always look at a selected object. This will be done without extra suply since each USB cable can provide 500mA. For now, the project only works under Linux. Some port is possible for MS Windows or other UNIXs but are not planed by the author.

This project deals with many problems: endembed systems, serial monitoring, USB development, realtime image recognition ... and many other really interesting topics.

The logbook might help in sorting troubles, and understanding the underneeth of everything.

All steps to build the project are detailed in the second appendix of the formal report. If you can not read the PDF files, download the sources of the reports, and read the Latex files.


In this documentation, I only explain how to build and use the board; I assume that you know how to modify files if required, and have the source tree of your kernel so that it is possible to compile a driver. I dont say it is easy; I just explain how I did it to make it work FOR ME.

To learn more about everything, I encourage you to read the Formal Report, at least the abstract and the introduction. You can also find pictas in other sections.


I have a segfault when launching the monitor

When sending the key, the monitor "Did not receive expected char".

Echos are not expected values.

ASL can not compile the code: usb08.asm(24) : error : address overflow

ASL compiles fine, but p2hex returns a 0 byte file

Where can I buy some 68HC908JB8 ?

Why cant I find any MC68HC908JB8JP any more ?

Possible problems

While uploading the firmware, if something goes wrong, the first thing to do is to edit the Makefile and remove '-e' in 'MON_OPT'.

To make sure the chip is blank, use

        make erase

AND POWER CYCLE THE CHIP BY UNPLUGING THE POWER FOR AT LEAST 2 to 10s ( depending on the capacitor you have used on the board) Remember that when you change the security key, or want to enter or exit monitor mode, you must always power cycle the board. It sometimes happens that the LEDs come off but there is still enough current in the capacitors to keep memory state in the chip if you use big capas. So if you encour any problem, wait at least 2 to 10s before replugging the board.


If you need to contact me, you can find my email in my CV. See head page. I am open to any suggestions, even bad criticises.