It’s loud, annoying, and fun — cut out the parts on a CNC router, then motorize them with a cheapo bench grinder (we found the perfect one at Harbor Freight). A great CNC project from MAKE fabricator Dan Spangler, designed with a traditional 5/6 two-tone sound ratio like the classic World War II sirens. WEEEEEEEEEEEOOOH!
Use data loggers and DIY sensors to map temperatures where you live. Towns are hotter than countryside, parking lots are scorching compared to green fields — what else can you discover? Another great amateur science project from Forrest M. Mims III, who shows you how to build and mount simple sensors and then deploy them on cars to take mobile transects, then use the data to create temperature maps.









