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zeros. In the 1990s, experimentation began with what was
called Free Hardware. Like free software, the “free” in free
hardware refers to the end user’s freedom — not to the
price of the hardware. However, unlike the software realm,
the terms free hardware and open hardware are
synonymous, and carry no political baggage. So, feel free
to use whichever term you prefer.
The free hardware idea was to design a physical
object; a printed circuit board, a motor, an airplane, or
whatever you can imagine. The schematics, mechanical
drawings, or other specifications for the design are then
released under a license that protects the user’s rights;
their right to use the design for any purpose, to modify it,
and to redistribute it.
One of the early pioneers of this effort was Diehl
Martin, known as Marty to his friends. Marty begin
designing printed circuit boards that were popular with
electronics and robotics hobbyists. He named each new
board after a type of breakfast food, such as Donut,
Flapjack, or Grits. The designs were released on his website
(known as FreeIO.org) and users could download the
plans and build the boards, or even modify and improve
the designs. Software developers collaborated with him to
introduce drivers for his boards into the Linux kernel.
Within a few years, the idea caught on and everyone was
Some free hardware designs have now became quite
popular — such as the Arduino, BeagleBoard, and
Raspberry Pi microcontrollers — and the RepRap 3D printer.
You may have heard of the Open Source Ecology group’s
GVCS project which is releasing open source designs for
the 50 industrial machines they deem necessary to
maintain civilization (e.g. sawmills, tractors, induction
furnaces, and the like).
This brings us to robots. Robots are hardware, so why
not create a robot design that can be released under a free
license? This has a lot of important advantages for robotic
hobbyists and the research community alike. Robots can be
expensive and time-consuming to build. Robot builders
often spend years duplicating the work of others instead of
making steady improvements. As an example, compare the
autonomous mobile robots built by William Grey Walter in
the late 1940s to robots built by hobbyists today. Little has
changed except the materials.
He used vacuum tubes while we use solid-state chips.
However, Walter’s robots were complex behavior-based
designs that could easily win “best of show” if brought to
any modern robot club contest.
Part of the reason we haven’t gotten better at building
robots is that we keep re-inventing and re-building the
same basic designs over and over instead of re-using
designs and making incremental improvements like we do
1) The design must be for a complete mobile robot,
not just part of a robot such as a manipulator arm.
2) The design documents (e.g., CAD files, schematics)
must be available under a free license (i.e., a license that
protects the user’s four basic freedoms as with FLOSS
software — a license with commercial-use restrictions
cannot qualify as open).
3) At least one working robot must have been
developed and demonstrated. Projects that are in the
planning stages didn’t make the list. I wanted designs
already proven in the real world.
One note about software licenses. Several projects
have used a CC license for their software. While this can in
some sense be construed as open source, it is against the
recommendations of both the Creative Commons
organization, the Free Software Foundation, and the Open
Source Initiative. Using a CC license on software presents
potential legal problems for the end users because the
license does not distinguish between object and source
code. This is intentional as the CC licenses were meant to
apply to other types of works, not software.
Use of a CC license on software also makes that
software incompatible with many valid open source
licenses. For hobby users, it’s a distinction not worth
worrying about, but for commercial users it is a serious
legal issue and usually means the software will have to be
discarded and replaced with new software licensed under
an accepted GPL-compatible license.
If you are the creator or maintainer of a free or open
project, remember never to use a CC license for the
software elements of your project!
The designs provided here meet the three criteria listed
previously. Each of these robot projects are available under
a license that will allow you to build them, modify them,
sell them, redistribute them, or do just about anything else
you want with them — provided, of course, that you pass
on the same license terms to the next user.
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