DIY membrane nitrogen generator for home brewing nitro cold brew and beer. 50L/h output at 99.5%+ purity, 100 PSI, ~$2,200 build. Includes KiCad PCB, STM32 firmware, SolidWorks CAD, and full P&ID. Open source hardware alternative to $4,500+ commercial units.

iGulu Home Brewing Bible — the open-source canonical reference for home brewing and fermentation. Six books: Craft Beer, Orchard & Vine, Living Culture, Sparkling Creations, Fermentation Lab. CC BY-NC-SA 4.0, device-neutral, founded by Shu Zhang (founder of iGulu).