Electronics Guide

Permissive Licenses

Permissive licenses impose minimal restrictions on how designs can be used. The CERN Open Hardware Licence version 2 Permissive (CERN-OHL-P) allows users to use, modify, and distribute designs freely, requiring only attribution to the original creators. Similarly, the Solderpad Hardware License provides permissive terms specifically adapted for hardware from the Apache Software License.

These licenses enable maximum flexibility for commercial adoption, as companies can incorporate open designs into proprietary products without obligation to release their modifications. This approach encourages broad adoption but may result in improvements remaining proprietary.

Copyleft and Reciprocal Licenses

Copyleft licenses require that derivative works be released under the same or compatible terms. The CERN Open Hardware Licence version 2 Strongly Reciprocal (CERN-OHL-S) exemplifies this approach, ensuring that improvements to open designs remain available to the community. The GNU General Public License (GPL) is sometimes applied to hardware, particularly for firmware and accompanying software.

The CERN-OHL-W (Weakly Reciprocal) provides a middle ground, requiring reciprocity only for modifications to the original design while allowing combination with proprietary components without triggering copyleft obligations for the entire system.

Creative Commons and Documentation

Creative Commons licenses are commonly used for hardware documentation, tutorials, and non-functional design elements. The CC BY (Attribution) and CC BY-SA (Attribution-ShareAlike) licenses are popular choices for educational materials accompanying hardware projects. However, Creative Commons explicitly recommends against using their licenses for hardware designs themselves, as these licenses were developed for creative works rather than functional designs.

Choosing an Appropriate License

Selecting the right license depends on project goals and community values. Projects seeking maximum adoption may prefer permissive licenses, while those prioritizing community contribution and preventing proprietary capture may choose copyleft approaches. Many projects use different licenses for different components, such as a permissive license for hardware designs and GPL for firmware.

Version Control for Hardware

Version control systems like Git have become essential tools for managing hardware design files. While originally developed for software source code, these systems effectively track changes to schematic files, PCB layouts, and documentation. Projects typically store design files in text-based formats when possible to enable meaningful diff comparisons between versions.

Platforms like GitHub, GitLab, and Gitea host thousands of open hardware projects, providing not only version control but also issue tracking, project management, and community features. Some specialized platforms like Upverter and Flux offer integrated electronic design tools with built-in version control and collaboration features.

Design Review and Quality Assurance

Peer review processes help ensure design quality in open hardware projects. Contributors submit proposed changes through pull requests or merge requests, which community members then review for correctness, adherence to standards, and compatibility with project goals. Many projects maintain design guidelines and checklists that reviewers use to evaluate contributions.

Automated design rule checks (DRC), electrical rule checks (ERC), and simulation help catch errors before they propagate into manufactured hardware. Some projects integrate these checks into continuous integration pipelines, automatically validating designs when changes are proposed.

Documentation Standards

Comprehensive documentation distinguishes successful open hardware projects. Beyond design files, projects typically provide assembly instructions, bills of materials with sourcing information, test procedures, troubleshooting guides, and user manuals. Good documentation enables others to reproduce, modify, and build upon the design.

The Open Source Hardware Association certification program encourages thorough documentation by requiring projects to meet specific criteria for design file availability and completeness. Certified projects display the OSHW certification mark, signaling their commitment to openness.

Community Governance

Successful open hardware projects establish clear governance structures that define how decisions are made, how contributions are evaluated, and how conflicts are resolved. Governance models range from benevolent dictator structures where a single maintainer makes final decisions to more democratic approaches with steering committees and voting processes.

Codes of conduct establish expected behavior within project communities, creating welcoming environments for diverse contributors. Many projects adopt established codes like the Contributor Covenant, adapting them to their specific community needs.

Arduino

Arduino stands as perhaps the most influential open hardware project, having introduced millions of people to electronics and embedded programming. The platform combines open-source hardware designs for microcontroller development boards with an open-source software development environment. Arduino's success demonstrated that open hardware could achieve commercial viability while maintaining community values.

The Arduino ecosystem has spawned countless derivative boards, shields, and compatible products, illustrating how open designs enable an entire industry of compatible products. The project's influence extends beyond its own products to shaping expectations for documentation, ease of use, and community support in the maker movement.

Raspberry Pi

While not fully open source in its hardware design, the Raspberry Pi Foundation has released extensive documentation and has fostered an enormous ecosystem of open add-on boards (HATs) and accessories. The platform's low cost and educational focus have made it a cornerstone of maker and educational electronics projects worldwide.

RISC-V

RISC-V represents open-source principles applied to processor architecture itself. This open instruction set architecture (ISA) allows anyone to design and manufacture RISC-V compatible processors without licensing fees. The RISC-V ecosystem includes numerous open-source processor implementations, development tools, and supporting infrastructure.

Major technology companies have adopted RISC-V for various applications, validating the approach of open processor architectures. The RISC-V International organization coordinates development of the specification while maintaining its open nature.

Open Source Ecology

Open Source Ecology develops the Global Village Construction Set, a collection of 50 industrial machines needed to build a small civilization with modern comforts. This ambitious project applies open-source principles to heavy machinery, agricultural equipment, and manufacturing tools, demonstrating the breadth of applications possible with open hardware.

OpenPCR and Open Science Hardware

The OpenPCR project created an open-source thermal cycler for DNA amplification, making molecular biology techniques accessible to educators and citizen scientists. This project exemplifies the growing open science hardware movement, which develops open laboratory equipment to democratize scientific research.

Organizations like the Gathering for Open Science Hardware (GOSH) coordinate efforts to develop open scientific instruments, sharing designs for microscopes, spectrometers, environmental sensors, and other laboratory equipment.

Electronic Design Automation Tools

KiCad has emerged as the leading open-source electronic design automation (EDA) suite, providing schematic capture, PCB layout, and simulation capabilities. Its native file formats are text-based and well-documented, enabling version control and third-party tool integration. Major hardware companies including CERN and Digi-Key have contributed to KiCad development.

Other open-source EDA tools include gEDA, Fritzing for beginner-friendly design, and LibrePCB. These tools ensure that open hardware designs can be edited and manufactured without requiring expensive commercial software licenses.

Mechanical Design Tools

FreeCAD and OpenSCAD provide open-source mechanical design capabilities for enclosures, mounting brackets, and other physical components. OpenSCAD's programmatic approach to 3D modeling aligns well with version control practices, as designs are represented as text-based scripts.

File Format Considerations

Open hardware projects should prefer open, documented file formats whenever possible. Industry-standard formats like Gerber for PCB fabrication and STEP for mechanical interchange ensure designs can be manufactured regardless of the tools used to create them. Projects should also include source files in their native formats alongside export formats.

PCB Fabrication Services

Low-cost PCB fabrication services have dramatically reduced barriers to hardware production. Services like JLCPCB, PCBWay, and OSH Park offer affordable prototype quantities, enabling individuals and small teams to manufacture professional-quality boards. Many of these services support direct upload of design files from popular EDA tools.

Assembly Options

Surface mount technology and increasing component miniaturization have made hand assembly challenging for many designs. PCB assembly services now offer turnkey manufacturing where they source components and assemble boards, though this increases cost and minimum order quantities. Some services specialize in small-batch assembly suitable for open hardware projects.

Component Sourcing

Comprehensive bills of materials with multiple supplier options help ensure designs can be built despite component availability fluctuations. Open hardware projects increasingly include component lifecycle information and suggest alternatives for parts that may become unavailable.

Business Models

Several business models support commercial open hardware ventures. Companies may sell assembled hardware while releasing designs, offer premium support and customization services, or provide manufacturing at scale more efficiently than individuals could achieve. Crowdfunding platforms have launched numerous open hardware products, validating market demand before production.

SparkFun, Adafruit, and Seeed Studio exemplify successful businesses built around open hardware, contributing designs back to the community while sustaining profitable operations through manufacturing, curation, and support services.

Accelerated Innovation

Open designs enable rapid iteration by allowing developers to build upon existing work rather than starting from scratch. Reference designs and proven subsystems reduce development time and risk. Companies increasingly release reference designs openly to encourage ecosystem development around their components.

Education and Workforce Development

Open hardware has transformed electronics education by providing affordable, well-documented platforms for learning. Students can study real-world designs, modify them, and understand how products work at every level. This transparency develops deeper understanding than working only with closed commercial products.

Standardization and Interoperability

Open hardware projects have established de facto standards in various domains. Arduino shield pinouts, Raspberry Pi HAT specifications, and Feather form factors enable an ecosystem of compatible add-on boards from multiple vendors. These community-driven standards often prove more responsive to user needs than traditional standards processes.

Supply Chain Transparency

Open hardware documentation typically includes detailed bills of materials, providing transparency into component sourcing that closed products lack. This transparency supports right-to-repair initiatives and enables users to make informed decisions about the products they use.

Manufacturing Economics

Hardware production involves significant fixed costs for tooling, setup, and minimum order quantities. These economics can make small-scale open hardware projects challenging to sustain commercially. The gap between releasing a design and achieving cost-effective manufacturing at scale represents a significant barrier.

Liability and Safety

Physical products can cause harm, raising liability concerns for open hardware projects. Designs for safety-critical applications require appropriate warnings, testing, and certification that may exceed community project capabilities. Users who manufacture open designs assume responsibility for ensuring safety compliance in their jurisdiction.

Intellectual Property Considerations

While copyright protects design documentation, hardware functionality may be covered by patents. Open hardware projects must navigate patent landscapes, and some projects explicitly include patent grants in their licenses. Contributors should understand the intellectual property implications of their contributions.

Maintaining Long-Term Viability

Component obsolescence affects all electronics, but open hardware projects may lack resources for ongoing maintenance. Designs must be updated as components become unavailable, requiring sustained community engagement. Projects should plan for long-term maintenance from their inception.

Using Open Designs

Begin by exploring existing projects on platforms like Hackaday.io, GitHub, and OSHWA's certification directory. Study how successful projects structure their documentation and design files. Build existing designs to understand both the hardware and the community practices surrounding it.

Contributing to Projects

Most open hardware projects welcome contributions beyond design work. Documentation improvements, bug reports, testing, and community support all provide valuable contributions. As familiarity grows, contributors may propose design improvements or new features.

Creating Open Hardware

When creating open hardware, plan for openness from the beginning. Choose appropriate licenses, use open file formats and tools when possible, and document thoroughly. Consider seeking OSHWA certification to demonstrate commitment to open principles. Engage with existing communities to learn best practices and find collaborators.