The goal of the Volksswitch design is to put its construction and assembly as close to the individual with disabilities as possible. That means making it available to therapists, ATPs, and family members. Pushing the construction of the switch as close as possible to the user ensures that the user will play a central role in defining its capabilities, look and feel with the result being a device that better fits the needs, desires and personality of its user.
The first implication of this design goal is that it must be low in cost and simple to assemble & maintain. Cost control begins with the choice of 3D printer and extends to the materials and parts that comprise the device. Simplicity of assembly and maintenance begin with assuming no special skills beyond “insert tab A into slot B” and “righty tighty / lefty loosey”. One should assume that the individual assembling the switch can use a 3D printer to produce parts and can order the necessary pre-built parts from a manufacturer but the extent of their electronic skills may not go much beyond cutting a wire to length and stripping off a specified length of insulation.
The second implication of this design goal is that it must demonstrate inherent customizability and personalizability – again with the intent of providing the best fit possible for the individual who will be using it. Some elements of customization and personalization can be supported easily and proactively. These tend to fall into the “one from column A and one from column B” form. Further customization of fit requires direct tweaking of the design itself. Unfortunately, the most feasible format to supply designs to our audience (STL files) is static in its nature. Given the current state of 3D modeling and printing tools, supporting complete customization, requires access to a 3D modeling tool and therefore a level of technical ability, and possibly cost, than we wish were necessary.
Any design is meaningless without a clear statement of what the requirements are for the device. In addition to the fundamental requirement that the switch close a circuit via pressure applied to a relatively large surface, the Volksswitch has these additional requirements:
The design must:
1 – support being constructed by individuals closest to the individual with a disability (e.g., therapists, AT professionals, family members):
- can be 3D printed on a consumer accessible printer (i.e., printer cost <= $250)
- each instance of the switch can be printed and assembled for less than $20
- can be assembled and disassembled with no special skills or equipment (e.g., does not require soldering skills and equipment, components bolt/snap/tape/glue together)
2 – support trouble shooting via simple part-replacement techniques
3 – support personalization of aesthetics (e.g., user-specified colors and shapes, activation surface texture, and tactile activation travel characteristics)
4- support simple customization of features and functions:
- activation distance and activation pressure
- support for externally powered elements (e.g., adapted toys)
- support for internally powered elements (e.g., visual /auditory / tactile feedback, wireless interfaces)
- support for common mounting and positioning solutions
- supports simple scaling of the components to meet a variety of applications and abilities
5 – support simple modification to better fit the needs and desires of the individual with a disability without the destruction of the component that is being replaced
6 – support simple, end-user replacement of components with limited life (e.g., batteries)
7 – exhibit high reliability simply by avoiding known, low reliability configurations and components
8 – support simple and low/no-cost design customization if the supplied designs fail to fit the needs and desires of the individual with a disability
9 – many aspects of the design should be reusable and extensible across new switch types, new form factors, and alternative technologies. An optimal design will have reusable elements that facilitate porting the concepts (or at least don’t hamstring the porting) to other implementation technologies (e.g., injection molding, laser sintering, stereolithography) or other form factors – e.g., how many of the POC design elements could be reused if a switch was created based on this form factor:
