Hardwire BEC enclosure for first alert smoke alarm

thingiverse

I got fed up by smoke alarm chirping even with pretty fresh battery, so printed this enclosure to hold a small buck converter, which will stepdown the 12V line to 3V for the smoke alarm. The buck converter is the smallest type you can find, like this. https://www.amazon.com/dp/B01MQGMOKI/ And I use the golden long tail fasterner for paper as the battery contact: https://www.quill.com/officemate-round-head-fasteners-gold-100-box-99814/cbs/061722.html Adjust buck converter to step down to about 3.0~3.1v, and then wire up the gut as the picture. Solder the power output (3V) end to the long tail fastener, and add some kind of wire connector to the power source end (12V for me). I use JR connector. Poke a hole on the battery holder on your first alert alarm ( I just use my soldering iron ), then assemble the buck converter + wiring and the printed battery holder, put it into the smoke alarm Wire it up from a 12v power source, then you should have converted your battery powered smoke alarm to hard wired. As a bonus.. put that 12v power source on a UPS, then it should still work a while even if the power is out.