Personal fabrication offers a potential alternative to mass production for the creation of hardware. This requires effective use of the available fabrication processes, such as 3D printing, laser cutting, and printed circuit board fabrication. As the Arduino case study demonstrates, the success of open source hardware also depends on a number of other factors, like the complements of the hardware itself and the business decision of various actors. Bringing open source hardware into our daily lives (as I try to do in my research) requires careful design of the devices themselves and the process of involving people in their production. Personal fabrication suggests new design principles. The effectiveness of these, and broader questions about the future of technology, will determine the extent to which digital technology can make peer production feasible as an alternative to mass production for hardware.