Open source hardware explained
Open source hardware refers to computer and electronic hardware that is designed in the same fashion as free and open source software (FOSS). Open source hardware is part of the open source culture that takes the open source ideas to fields other than software.
The term has primarily been used to reflect the free release of information about the hardware design, such as schematics, bill of materials and PCB layout data, often with the use of FOSS to drive the hardware.
With the rise of reconfigurable programmable logic devices, the sharing of logic designs is also a form of open source hardware. Instead of sharing the schematics, hardware description language (HDL) code is shared. HDL descriptions are commonly used to set up system-on-a-chip systems either in field-programmable gate arrays or directly in application-specific integrated circuit designs. HDL modules, when distributed, are called semiconductor intellectual property cores, or IP cores.
Rather than creating a new license, some open source hardware projects simply use existing, open source software licenses.
In addition to existing software licenses, several new licenses have been proposed; these licenses are designed to address issues specific to hardware designs. In these licenses, many of the fundamental principles expressed in open source software (OSS) licenses have been "ported" to their counterpart hardware projects. Organizations tend to rally around a shared license. For example, Opencores prefers the LGPL ; FreeCores insists on the GPL ; Open Hardware Foundation promote "'copyleft' or other permissive licenses" ; and the Balloon Project wrote their own license  . New hardware licenses are often explained as the "hardware equivalent" of a well-known OSS license, such as the GPL, LGPL, or BSD license.
Despite superficial similarities to software licenses, most hardware licenses are fundamentally different: by nature, they rely on patent law, rather than copyright law. Whereas a copyright license may control the distribution of the source code or design documents, a patent license may control the use and manufacturing of the physical device built from the design documents. This distinction is explicitly mentioned in the preamble of the TAPR Open Hardware License.
- The TAPR Open Hardware License: drafted by attorney John Ackermann, reviewed by OSS community leaders Bruce Perens and Eric S. Raymond, and discussed by hundreds of volunteers in an open community discussion
- Balloon Open Hardware License: used by all projects in the Balloon Project
- Although originally a software license, OpenCores encourages the LGPL
- The Open Graphics Project uses a variety of licenses, including the MIT license, GPL, and a proprietary license.
- Hardware Design Public License: written by Graham Seaman, admin. of Opencollector.org
There are several "open source hardware" CPUs, typically implemented as a soft microprocessor.
- OpenSPARC is an open-source processor project to which Sun Microsystems have contributed the UltraSPARC T1 and UltraSPARC T2 multicore processor designs.
- OpenRISC is a group of developers working to produce a very high performance open source RISC CPU.
- LEON is an open source 32-bit SPARC-like CPU created by the ESA. It's the standard CPU for the European Space Industry.
- OpenCores is a foundation that attempts to form a community of designers to support open-source cores (logic designs) for CPUs, peripherals and other devices. OpenCores maintains an open-source on-chip interconnection bus specification called Wishbone.
Several designs include a CPU:
- Arduino, an open-source physical computing platform based on a simple I/O board and a development environment that implements the open source Processing / Wiring language.
- Freeduino - open-source electronics prototyping platform derived from Arduino.
- ASoC (ALSA System on Chip).
- PLAICE - The PLAICE is an open source hardware and software project developing a powerful in-circuit development tool that combines in one device the features of a FLASH Programmer, Memory Emulator, and High Speed Multi-Channel Logic Analyzer. It runs uClinux.
- MIDIbox The MIDIbox project is an open source modular DIY hardware and software platform for MIDI devices like controllers, synthesizers, sequencers
- Monome 40h - A reconfigurable grid of sixty-four backlit buttons, used via USB. A limited batch of 500 monome 40h has been produced. All the design process, design specifications, firmware and PCB schematics are available online
Machines and tools
- Small wind turbines: To assist people in the developing countries, and hobbyists alike, several projects have been open-sourced, e.g. the Jua Kali wind turbine, Hugh Piggot's wind turbine, ForceField Wind Turbine, et cetera
See also: Open-source robotics.
A range of open design hardware can be used in home automation.   Examples are
- RONJA - Open source Free Space Optic system, DIY in a garage, 10 Mbit/s full duplex/1.4 km
- LED Throwies - non-destructive graffiti and light displays.
Notes and References
- From OpenCollector's "License Zone": GPL used by Free Model Foundry and ESA Sparc; other licenses used by Free-IP Project, LART (defunct), GNUBook (defunct).
- For a nearly-comprehensive list of licenses, see OpenCollector's "license zone"
- http://opencores.org/faq.cgi/section/2/2.4#2.4 Item #2.4 "Who owns opencores?"
- http://www.freecores.org/wiki/Main_Page FreeCores Main Page
- http://www.openhardwarefoundation.org/index.php?option=com_frontpage&Itemid=70 Open Hardware Foundation, main page
- http://balloonboard.org/licence.html Balloon License
- http://www.tapr.org/ohl.html TAPR Open Hardware License
- http://technocrat.net/d/2007/2/5/14355 transcript of all comments
- See "Are we going to get the 'source' for what is on the FPGA also?" in the Open Graphics Project FAQ, retrieved 25 November 2008
- http://searchenterpriselinux.techtarget.com/news/interview/0,289202,sid39_gci1204142,00.html Open source router challenges proprietary networking market
- http://www.halfbakery.com/idea/Open_20Source_20Hardware_20Initiative Halfbakery: Open Source Hardware Initiative<
- http://opendotdotdot.blogspot.com/2008/07/open-domotics.html Open domotics
- http://www.domoticspoint.com/archive/2006/01/06/home-automation-expensive-try-open-source/ Open design domotics
- http://www.freescale.com/files/microcontrollers/doc/support_info/DIGIBUTLER_1.pdf Digibutler review