Making copyleft hardware

The spirit of the Free Software revolution has also reached
the more traditional world of hardware, but many challenges
remain. 
This presentation will review the objectives and constraints
of copyleft hardware,
examine their practical implications on design, tools, and the
general workflow,
and illustrate how this works in real life with examples from 
the Qi-Hardware project (Ben NanoNote, Ben-WPAN, Milkymist One, 
and others).