Book excerpt: Open-Source Lab: How to Build Your Own Hardware and Reduce Scientific Research Costs details the development of the free and open-source hardware revolution. The combination of open-source 3D printing and microcontrollers running on free software enables scientists, engineers, and lab personnel in every discipline to develop powerful research tools at unprecedented low costs.After reading Open-Source Lab, you will be able to: - Lower equipment costs by making your own hardware - Build open-source hardware for scientific research - Actively participate in a community in which scientific results are more easily replicated and cited - Numerous examples of technologies and the open-source user and developer communities that support them - Instructions on how to take advantage of digital design sharing - Explanations of Arduinos and RepRaps for scientific use - A detailed guide to open-source hardware licenses and basic principles of intellectual property