Because smoke detectors are now mandatory in Belgium and the only ones that look good are expensive, I modelled this new shell for a cheap one. The original used 3 flat batteries, this one uses a single 9V battery. The original I'm using is in one of the pictures, as well as the PCB that was inside. I have no idea how reusable this is for anyone else. I added the design files for easy remixes and adaptations.

PS: This is a WIP, I have not printed these parts yet.