Archos + Arduino via USB?
Brief: yes, possible. You can connect Arduino over USB to Android.
I have not tried it yet, so I can not give you first hand experience information.
Beginning of 2011 a hacker called inopiaaardbei made a solution called: ÔÇ£MicrobridgeÔÇØ using the Arduino USB host bridge and wrote the software to use the Android Debug Bridge (ADB) to communicate between the Android device and Arduino board via USB.
The Android device (your Archos) becomes a slave, the Arduino becomes the host.
Total cost on the Arduino side to get started? About 50 euro.
Due to the use of ADB it should run on all Android devices, including any Android phone and Archos tablets.
See more here ÔÇô http://wp.me/pCAFq-h5
. Links to his google code solution are in the post.
A direct link to the google code repository is here: http://code.google.com/p/microbridge/