The images in the post are CadSoft EAGLE (http://www.cadsoftusa.com/download-eagle/ http://www.cadsoftusa.com/download-eagle/), but it's mainly showing the plug

The images in the post are CadSoft EAGLE (http://www.cadsoftusa.com/download-eagle/ http://www.cadsoftusa.com/download-eagle/), but it's mainly showing the plugin made by SnapEDA. EAGLE has been around for ages and has its quirks, but it is used by lots of engineers (from big companies to makers), has a freeware version available, and is supported on Mac & Windows, so it's a good place to start. Here are other free/low-cost tools (considering it's a side project) that might be helpful: - KiCad (http://kicad-pcb.org/download/ http://kicad-pcb.org/download/) is a free tool made by CERN that is gaining adoption quickly (Mac & Windows). - CircuitMaker (http://www.circuitmaker.com http://www.circuitmaker.com) is a new free tool from Altium (Windows only). A lot of people like Altium's user interface, so might be worth trying this if you're ok with your designs being public. - Quadcept (http://www.quadcept.com http://www.quadcept.com) - haven't tried it but have heard good things; it's a pretty new free web-based PCB design tool out of Japan