Rick Pannen designed the case for his iPhone-mountable Geiger counter in FreeCAD, milled it out of a solid block of polyoxymethylene (aka “acetal”), and loaded it with a custom-milled PCB and a surplus SI-29BG Russian Geiger-Müller tube from eBay. The circuit itself was designed by BroHogan of DIYGeigerCounter, and it interfaces with the phone through the audio jack. The software is ND Apps’ Geiger Bot. Rick describes this as a “first prototype.” Can’t wait to see the next one! [Thanks, Rick!]

iPhone Geiger counter