Journal:What is the "source" of open-source hardware?

Full article title	What is the "source" of open-source hardware?
Journal	Journal of Open Hardware
Author(s)	Bonvoisin, Jérémy; Mies, Robert; Boujut, Jean-François; Stark, Rainer
Author affiliation(s)	Technische Universität Berlin, Grenoble Alpes University
Primary contact	Email: jeremy dot bonvoisin at tu-berlin dot de
Year published	2017
Volume and issue	1(1)
Page(s)	5
DOI	10.5334/joh.7
ISSN	2514-1708
Distribution license	Creative Commons Attribution 4.0 International
Website	https://openhardware.metajnl.com/articles/10.5334/joh.7/
Download	https://openhardware.metajnl.com/articles/10.5334/joh.7/galley/12/download/ (PDF)

Abstract

What “open source” means once applied to tangible products has been so far mostly addressed through the light of licensing. While this approach is suitable for software, it appears to be over-simplistic for complex hardware products. Whether such a product can be labelled as open-source is not only a question of licence but a question of documentation, i.e. what is the information that sufficiently describes it? Or in other words, what is the “source” of open-source hardware? To date there is no simple answer to this question, leaving large room for interpretation in the usage of the term. Based on analysis of public documentation of 132 products, this paper provides an overview of how practitioners tend to interpret the concept of open-source hardware. It specifically focuses on the recent evolution of the open-source movement outside the domain of electronics and DIY to that of non-electronic and complex open-source hardware products. The empirical results strongly indicate the existence of two main usages of open-source principles in the context of tangible products: publication of product-related documentation as a means to support community-based product development and to disseminate privately developed innovations. It also underlines the high variety of interpretations and even misuses of the concept of open-source hardware. This reveals in turn that this concept may not even be clear to practitioners and calls for more narrowed down definitions of what has to be shared for a product to be called open source. This article contributes towards this effort through the definition of an open-source hardware lifecycle, summarizing the observed approaches to open-source hardware.

Keywords: open-source hardware, open design, open innovation, open-source innovation, open-source product development

Introduction

We are currently witnessing an increasing number of initiatives transferring product development and production from the private sector to the public. Enabled by the growing accessibility of affordable manufacturing technology, this is manifested in the expansion of the so-called “maker culture,” which takes action to install participational production as an alternative to industrial production. The emergence of this culture is interwoven with the phenomenon of open-source hardware (OSH), which transfers open-source principles (as defined by Open Source Initiative 2007) from their origins in software development to the world of physical objects. While these new practices are raising significant attention, they are still in their infancy and struggle to reveal their full economic, social, and environmental potential. One of the challenges they face is that sharing knowledge about atoms is not as frictionless as sharing bits.

Both practitioners and the scientific community generally acknowledge that online sharing of a piece of hardware is more difficult than the sharing of a piece of software (e.g., see discussion of this point by Raasch. Software is digital by nature; it is made of series of characters in a format that can be shared and displayed online without specific tools, with a text editor being enough. Hardware may need to be described through more complex constructs like 2D or 3D schematics, which may require more specific software to be edited and displayed. Based on the evaluation of a pool of 20 OSH projects whose products embedded both software and hardware components, Balka, Raasch, and Herstatt highlighted that hardware components were generally less documented than the software components. This result raises questions in terms of practice. When a piece of hardware is poorly documented, is it still open source? What does “less documented” mean? What are the minimal requirements for labeling a hardware product as "open source"?

In the absence of clear guidance on this issue, it is not easy to draw a line between which piece of hardware is open source and which is not, even when licensing terms may be clear. Unlike in software, attributing appropriate licences is not sufficient to call hardware open source. Given OSH is a sociotechnical phenomenon, the answer primarily depends on how the product documentation enables co-development and replication. This article seeks to provide guidance on which information sufficiently describes OSH. In other words, what is the source of OSH?

The objective of this article is to provide an overview of how current projects tend to interpret and make use of the concept of OSH. Its ultimate goal is to provide a deeper description of what OSH means based on the observation of actual practices. This is performed through the analysis of the “source”, i.e., the published documentation of 132 OSH products with the help of categorical criteria addressing the question “how open are OSH products?” It specifically focuses on the recent evolution of the open-source movement outside the domain of electronics and DIY to those of non-electronic and complex OSH products.

The remainder of the paper is structured as follows. In the next section the general context of emergence of OSH as an alternative product development pattern based on free distribution of information is depicted and characterized. Then definitions from practice communities and scholars are analysed and combined in order to provide a consolidated overview of the concept of OSH. After the definitions, the methodological approach for the acquisition of empirical data allowing the analysis of current practices of OSH documentation is introduced. The results produced by the application of this method are then described and interpreted. Finally, we summarize the findings into an original framework termed "OSH lifecycle," additionally summarizing observed approaches to OSH.

The context of open-source hardware

OSH is a relatively young phenomenon with projects emerging in the past decade, although it has several prominent examples already. Pioneering projects such as RepRap, Open Source Ecology, and Local Motors have certainly set a precedence to lift the air of mystery and aloofness of engineering ingenuity closely guarded for means of commercial appropriation. As to whether these are heralds of what Moritz et al. depict as disruptive changes on the upstream end of value chains toward value-co-creation, only time will tell. Clearly, this alternative course of action could take an active part in shaping the technological future. Indeed, there are already promising examples of successful businesses based on OSH for which the scientific community identified corresponding value creation models. These examples, together with the empirical evidence provided by free and open-source software, allow for a foreseeing of a flourishing future for OSH.

Like free and open-source software, OSH is an IT-enabled internet phenomenon. Fjeldsted et al., as well as Bonvoisin and Boujut, point out the integral part IT platforms play in fostering product-related data sharing and community-based product development, as well as the emergence of OSH-based business models. However, Raasch draws a contrast: compared with OSS development, the aspect of physical object design in OSH has strong impacts on required skills, tools, and infrastructure. This aspect is even increasingly salient as the focus of OSH progressively expands towards many other forms of hardware than electronic hardware, like mechanical, construction, medical, optical, agricultural, or textile hardware. From a design point-of-view, the degree of freedom in the problem-solution space introduced by their mechanical portion rises significantly. Howard et al. and Raasch, Herstatt, and Balka also illustrate how OSH is looking at the full spectrum of product complexity and different manufacturing strategies, from do-it-yourself (DIY) to industrial production.

The capacity of communities outside the closed and hierarchical environment of research and development (R&D) departments to develop complex and high-quality products remains a challenge; the largest majority of OSH products available to date are gadgets for hobbyists. As processes transform inputs into outputs, their structure is generally related to the product and project scope. OSH can be described as individual or participatory realization of a shared product design. Therefore, 3D printing designs shared by individuals on sites such as Thingiverse may classify as OSH, similar to large community-based efforts such as the E-Nable project. This makes a big difference in regards to the type of effort being structured for the realization of an open-source product. Hence, depending on the product scope and also the originator's intent to foster co-design, levels of interaction maturity differ starkly in OSH. A useful macro-level classification is offered by Camarinha-Matos et al., starting at networks, then moving to coordination, cooperation, and collaboration.

The conceptual space that supports collective spirit and collaborative problem solving is described by Maher, Paulini, and Murty. It is based on the three aspects of shared representation, motivation, and communication. They enable problem solving in collective design projects within a continuum from collected (individual) to collective intelligence. The latter is demarcated by collaborative generation of solutions as well as synthesis of individual solutions. From their study of collective design activities conclude that within the frame of what they call an inclusive nature of participatory design, individuals proactively self-organize and choose their own roles as well as period of involvement. The maturity of this participatory nature may in fact be the primary determinant of collective design projects.

Social dynamics in crowds are context-dependent, however. In the OSH context, from all of the above, communities can be viewed as socially formed groups of heterogeneous actors who co-create OSH products. Depending on the participatory roles of actors, they may engage as followers, replicators, developers, or community managers. In the frame of open innovation, West and Lakhani describe them as actor volunteers lacking of organizational affiliation. Due to partial influence of market-based factors, this role may somewhat reflect the notion of people giving away their time and effort without any monetary compensation. In addition, actors may as well include individuals, firms, and many other types of organizations.

Aksulu and Wade provide insight on how pure open-source systems set a community-based context of personal development, process learning, and effective technology outputs. In contrast, within the purely proprietary context, purpose is realized by the efficient generation of technology outputs within organizations with clear boundaries.

What exactly makes open-source processes effective seems to be rooted in the task environment. According to Lee and Cole, the trade-off between exploration and exploitation is made through a two-tier task structure of generated variations within the periphery, and selection and retention at the core. In their case study of the Linux kernel development project, they observe community-based knowledge creation in the form of an evolutionary learning process based on a culture of critical evaluations and peer learning. Moreover, Howison and Crowston describe collaborative development of OSS as an evolutionary process of incremental and independent tasks, by which a layer structure emerges task-by-task. They argue that added layers change the context over time and significantly reduce complexity of tasks. By gradually laying the foundation, previously unattainable tasks eventually may suddenly become easily achievable by individual developers, or simple workarounds may become obvious. This is in line with the concept of Maher et al. concerning the co-evolution of the problem and solution spaces, which describes how these dimensions influence each other during the design process. Collaborative evolutionary design on the activity level is key in explaining how solutions are generated effectively in open-source systems and needs to be further researched.

Definitions of openness from practice and research

This section reviews existing definitions from practice and identifies resulting implications in terms of published product-related documentation. These definitions are then matched with existing contributions from research in order to provide a comprehensive framework defining OSH. Results of empirical studies which challenge these definitions and show a more heterogeneous landscape of OSH are then presented and lead to the identification of two research questions addressed in this article.

Definitions from practice communities

The Open Source Hardware Statement of Principles 1.0 states that “open source hardware is hardware whose design is made publicly available so that anyone can study, modify, distribute, make, and sell the design or hardware based on that design.” It is based on the assumption that publishing a “design” (alternatively termed “documentation”) realizes the four freedoms of the open-source concept, which are reinterpreted in the context of tangible products as the freedom to study, modify, make, and distribute.

This definition is an adaptation of the original Open Source Definition by the Open Source Initiative to the realms of tangible products. Coined in the context of free and open-source software, it specifies requirements on two interwoven objects: the “software,” alternatively called the “product,” and the “source code.” It is implicitly accepted that the object called “source code” allows defining the object called “product” unambiguously in its depth and its entirety. In the case of software, this implicit prerequisite is automatically fulfilled, as a software product is the translation of a text written in programming language into a machine language by a deterministic algorithm. However, this is not the case for tangible products: what information has to be shared in order to allow any interested person to study, modify, make, and distribute a piece of hardware is not a simple question.

A closer look at the definitions of widely recognized OSH licences and current practices of OSH seeks to give some hints and shows that the four freedoms of open source tend to be supported by different document types or properties:

• The freedom to study (i.e., the right to access sufficient information to understand how the piece of hardware—referred herein as the product—works and to retrace the underlying design rationale as defined by Wang, Johnson, and Bracewell) can be supported by the publication of schematics, 2D, or 3D CAD files.
• The freedom to modify (i.e., the right to edit the product definition documents and to tweak or develop the product further for any purpose) can be supported by the publication of all documents in their original editable format.
• The freedom to make (i.e., the right to use the product definition documents in order to make—in other words to produce, to manufacture—the piece of hardware) can be supported by the publication of a bill of materials and assembly instructions.
• The freedom to distribute (i.e., the right to give or sell the product definition documents as well as the physical products fabricated with the help of these documents) is allowed by the publication of all documents under a licence which grants free redistribution, including for commercial purposes.

Definitions from scholarly research

Scholarly definitions—mostly stemming from innovation management research—deliver categories which are consistent with the Open Source Hardware Statement of Principles 1.0 without, however, giving further details on the nature of the documentation to be published.

Freedoms to study, to edit, and to make are consistent with the three factors of openness defined by Balka, Raasch, and Herstatt. They respectively term these factors "transparency," "accessibility," and "replicability." Transparency refers to the possibility for any interested person to access sufficient information to understand the product in detail without restriction (which equals the freedom to study). Accessibility refers to the possibility for any interested person to edit design information and therefore to further develop the product (which equals the freedom to modify). Replicability refers to the possibility for any interested person to physically produce the product (which equals the freedom to make). These three factors of openness are introduced as preconditions for three complementary behaviors on the part of the community surrounding the product: Transparency enables observation (and eventually feedback), accessibility enables further development (and eventually co-development), and replicability enables prototyping and production (and eventually co-production). What is missing in this contribution is the fourth factor of openness termed henceforth "commercial usability," which addresses the above listed freedom to distribute.

The four freedoms and corresponding factors of openness cover both “distinct and competing meanings” of openness identified by von Hippel: the permeability of the innovation process to the participation of external people and the public sharing of documentation. Transparency, replicability, and commercial usability are about sharing documentation publicly. Accessibility is about enabling the participation of external people in the design process. Aitamurto, Holland, and Hussain term two meanings of openness: process openness (whether the innovation process is open or closed) and product openness (whether the innovation outcome is open or closed). Huizingh defines open-source innovation as a result of both process and product openness. Raasch, Herstatt, and Balka particularly deliver the following definition: “open-source innovation is characterized by free revealing of information on a new design with the intention of collaborative development of a single design or a limited number of related designs for market or nonmarket exploitation.”

The coherent picture of OSH drawn by those definitions from practice and scholarly research is displayed in Figure 1. OSH builds upon product and process openness. Product openness results from the factors transparency, replicability, and commercial usability, which respectively address the freedoms to study, make, and distribute. Process openness results from the sole factor accessibility, which addresses the freedom to edit.

Figure 1. Forms of openness involved in open-source hardware

Theory-practice-gap

The few existing empirical studies of OSH deliver a picture from practice observations that is less strict than the ambitious theoretical approach summarized by Figure 1, beyond the misuses, which can be expected with the upcoming of a new concept.

Balka, Raasch, and Herstatt showed that factors of openness may be valued differently by development community members in the fields of consumer electronics and IT hardware. In the communities they analyzed, accessibility of software tended to play the largest role in the involvement of members, while transparency and replicability of software played a secondary role, and the openness of the related hardware played no role. They also highlighted that, as a result of the low importance given to hardware in those communities, hardware components were generally “less documented” than the software components. This raises the following research question:

RQ1 – To what extent are the four aspects of openness reflected by practitioners in the publication of product-related documentation? Do practitioners tend to employ the whole set of these factors, or do they tend to employ only subsets of these factors?

Based on interviews with originators of OSH products, Bonvoisin et al. defined the contours of two archetypes of projects developing OSH they termed "development communities" and "isolated innovators." Development communities are characterized by high process openness, adopt systematic and early release policies, and gather contributions from a larger and permeable group of people. On the contrary, isolated innovators are characterized by low levels of process openness. They do not gather contributions from the outside, but rather they release complete product documentations after product versions are fully developed. While the former are interested in integrating people from the outside during the product development process, the latter are more interested in broadcasting their innovation, i.e., enabling other people to produce it. This contradicts the statement made by Gacek and Arief that “the term 'open source' has been widely used to describe a software development process.” Findings reported by Bonvoisin et al. suggest on the contrary that motivations for publishing documentation may depend on the phase of the product lifecycle in which the community is supposed to play a role and raise the following second research question:

RQ2 – If factors of openness are understood by practitioners as optional, can we find typical patterns in the way practitioners decide to comply with specific factors of openness? Are these aspects related to specific product lifecycle phases?

Research approach and methodology

In order to address the research questions defined above, an empirical approach based on the systematic analysis of a representative group of OSH products, as well as their published documentation, has been adopted. This approach is similar to those adopted by Balka, Raasch, and Herstatt while avoiding two pitfalls limiting the validity of the produced results. The first is the use of unclear categories such as the size of the development community. As shown in Bonvoisin et al., belonging to a development community is a fickle concept which may be based on different types of activities (from pressing the button “I like” to bringing significant contribution to the product design), which are highly flexible over time and therefore difficult to measure objectively. The second is the use of subjective evaluation of the openness factors with the help of Likert scales. In contrast to the approaches of Balka, Raasch, and Herstatt, the research reported here strives at a systematic analysis of published documentation with the help of measurable indicators, from the part of an impartial observer.

In the following subsections, the approach adopted for the acquisition and the analysis of empirical data is presented. The first subsection introduces methodological choice made in focusing on non-electronic complex hardware products. The second subsection describes the method applied for the establishment of a representative pool of those products. The third subsection defines a set of criteria used to characterize products and their related documentation. The fourth subsection defines criteria for the assessment of openness factors based on the acquired data. The last subsection introduces a clustering method used for identifying typical patterns in the publication of OSH documentation.

Focus: Complex non-electronic hardware products

While the transfer of open-source principles from software to hardware historically and logically started with electronic hardware, other technologies are increasingly impacted by the phenomenon. The extension of open-source practices to non-electronic hardware such as mechanical products is of particular interest in terms of documentation. Electronic hardware is a thoroughly standardized field where components are purchased off the shelf. But this is not the case for mechanical hardware, where non-standardized free form components play a large role.

Also, particularly interesting is the consideration of complex products. Product complexity is defined by Jacobs as “a design state resulting from the multiplicity of, and relatedness among, product architectural elements.” This characteristic influences the level of professionalization required in the development and production of a given product. It also determines whether production can take place in either DIY or industrial production settings. Noteworthy is that, while DIY and OSH are two interwoven phenomena, not every OSH product is meant to be produced in a DIY production setting. Product complexity also relates to design effort in terms of resources consumed and process duration. Highly complex products tend to require inputs from multiple people and are more relevant for the topic of collaborative design.

In order to reflect the challenges faced by OSH products in terms of documentation, the methodological approach pursued in this article is to focus on the most challenging range of products. The underlying assumption is that “who can do more can do less,” so what applies to complex non-electronic hardware applies also to more electronic hardware and simple products. As a consequence, this article specifically focuses on the recent evolution of the open-source movement outside the domain of electronics and DIY to those of non-electronic and complex OSH products. It excludes the field of purely electronic hardware products. Not only is this methodological choice in consistency with the academic background of the authors situated in mechanical engineering and collaborative engineering design; it is also in line with the most recent advancement of the open-source concept on forms of hardware which are in the sphere of influence in these disciplines. It should be borne in mind that the huge achievements of the still much larger open electronic hardware field have paved the way for this development. In no way is the exclusion of this field in this study an indicator of its irrelevance. Rather, it is a matter of limiting the extent of the research undertaking.

As a result of this position, in the rest of the paper, “open source hardware” is used to refer to complex, non-electronic OSH.

Product selection

In contrast to previous research works aiming at grasping the contours of a phenomenon related to open source, e.g., sharing of 3D-printed designs (see Kyriakou, Nickerson, and Sabnis), no major centralized online entry point exists which aggregates relevant products in the context of OSH. While platforms such as GitHub or Thingiverse are playing this role for free and open-source software or 3D-printing communities, to date, there is no generally acknowledged and widely used online platform supporting open-source product development. These observations have been respectively made by Raasch and Howard et al. and are still valid. On the contrary, projects developing OSH products tend to use a wide variety of tools for collaboration and dissemination.

As a result, OSH products have been identified using conventional internet search engines using a snowball-effect approach. The results of this search have been screened through a restrictive criteria set in order to ensure a conservative evaluation of the phenomenon to be studied and to keep a deliberately narrow focus within the highly diverse field of open-source innovation (see for example Ehls on that topic). The following selection criteria have been applied:

• The product is the outcome of discrete manufacturing. Products of food and process industries such as yogurt, cement, chemicals, or plastic compounds are excluded.

• The product contains at least in-house, tangible, and non-electronic hardware, which includes mechanical or any other type of non-electronic physical elements (e.g., textile). It may eventually include electronic hardware and consequently software. Purely electronic hardware or software products such as Arduino or Linux are therefore excluded. In-house means that the piece of non-electronic hardware is "original equipment" created by the product originator and not a component bought off the shelf.

• The product is complex. While well-defined metrics assessing product complexity on a positive real scale have been proposed in the scientific literature (e.g., Rodriguez-Toro, Jared, and Swift ), using those metrics requires having sufficient access to detailed data such as the number of parts. This condition is difficult to satisfy in the context of observation of partly documented and defined products. Therefore, in the following analysis, the complexity of products is evaluated with a rule of thumb: products are considered as complex if they consist of more than two parts of different materials. Products such as business card holders, cell phone cases, or other 3D-printed gimmicks are out of scope. The objective here is to bring to the foreground those open-source products that are on the upper side of the complexity scale. In other words, to select the few complex ones and let aside the myriad of gimmicks that can be found on CAD file exchange platforms such as Thingiverse or Shapeways.

• The product is developed for functional rather than aesthetic purposes. Jewelry, artistic, and decorative items do not fulfill this criterion and therefore were not included.

• The product is at least partly defined, i.e., is provided with sufficient documentation to indicate that the product development maturity is equivalent or above the stage “system-level design” of the product development process as defined by Ulrich and Eppinger. Undeveloped product concepts are not considered. Thus, the focus delineates them from challenge platforms, which focus solely on capturing concepts from external participants.

• The product is labelled by its surrounding community as open source. The terms “open source,” “open-source hardware,” or “open hardware” are used in the published documentation as an adjective to qualify either the product or the activities around the product. This is quite a conservative criterion. A non-negligible number of projects adopt principles of OSH without necessarily fitting neatly into this conservative criterion.

• There are no systematic 1:1 relations between product, project, and community. For example, a community may be involved in more than one project and a project may involve the development of more than one product. However, in order to simplify the analysis, only one product per project and per community has been considered.

Data acquisition

For each of the selected products, two sets of descriptive criteria are defined. These are summarized in Table 1. The first set is dedicated to the characterization of the published product-related information. It translates in measurable terms the best practices of OSH as provided by the Open Source Hardware Association and complemented by a practice review performed prior to the reported research. In the absence of practicable indicators for assessing the quantity, the quality, or the relevance of a piece of information, simple binary criteria are used, which indicate the presence or the absence of a given piece of information or of a given property. The second set delivers contextual information about the product, the corresponding development project, as well as the surrounding product development community.

Table 1. Open-source hardware product characterization criteria. Ref. Name Description Part I – Criteria regarding shared product-related documentation a CAD files available Boolean value indicating whether CAD files or schematics of the non-electronic hardware are available online b CAD files aeditable Boolean value indicating whether the online released CAD files of the product are editable. CAD files are considered editable if they are released in their original format. They are not considered editable if they are only released in an export format such as PDF or STL, which does not allow further modifications. c Assembly instructions available Boolean value indicating whether instructions for building the non-electronic hardware are available online d Assembly instructions editable Boolean value indicating whether the published assembly instructions are editable. Assembly instructions are considered editable if they can be edited in a web 2.0 environment or downloaded as editable files. A file is furthermore considered editable if it is released in its original format. It is not considered as editable if it is only available in an export format such as PDF. e Bill of materials available Boolean value indicating whether a bill of materials relative to the non-electronic hardware is available online f Bill of materials editable Boolean value indicating whether the published bill of materials is editable. A bill of materials is considered editable if it can be edited in a web. 2.0 environment or downloaded as an editable file. A file is furthermore considered editable if it is released in the original format. It is not considered editable if it is only available in an export format such as PDF. g Guidelines for participation Boolean value indicating whether guidelines for participation or a dedicated call for contribution are provided to potential contributors h Commercial usage allowed Boolean value indicating whether the licence applied to the non-electronic hardware allows commercial usage of the published content. If no licence is applied, the criterion is set to false. Part II – Criteria regarding contextual information i License Licensing scheme used for the publication of the non-electronic hardware j Contains electronics Boolean value indicating whether the product contains electronic hardware components as well k Maturity Defines the maximum maturity level achieved by one of the eventual versions of the product over time. Five maturity levels are defined in the order of increasing liability risk:   1. Design - There is only a theoretical design that is still to be fully developed. No liability of the product originator applies. 2. Prototype - The early design phases have been completed and the first functional prototype has been built. No liability of the product originator applies. 3. Production/DIY - The product is fully defined and documented and can be replicated. No liability of the product originator applies. 4. Production/Kit - The product is sold by a commercial actor as a kit. Limited availability applies to the vendor. 5. Production/full product - The product is sold by a company as a finished product. Full availability applies to the vendor. l Status of the community Binary value indicating whether the community is active. The community is considered inactive in case no activity (encompassing either product development or sales and marketing) can be detected on the website or the collaboration platforms within one year. m Product category Classification of the products in product groups

Notes

This presentation is faithful to the original, with only a few minor changes to presentation. In some cases important information was missing from the references, and that information was added. The original article lists references alphabetically, but this version—by design—lists them in order of appearance. To more easily differentiate footnotes from references, the original footnotes (which where numbered) were updated to use lowercase letters. Some footnotes simply referencing web pages were either turned into inline links or removed entirely for being superfluous. In the original, the citation for the Free Software Foundation 2015 is inadvertently missing; the presumed citation is added in this version.