EnOcean PTM21x Mount for DE Light Switch (Merten)

I was looking for a way to make my light switches smart, but ran into some limitations (no neutral wire, very little space behind the switches), so I decided that I wanted something that simply attaches on top of the existing light switch.

EnOcean switch modules seemed to be a perfect fit for this use-case since they are low-profile while still having a very satisfying click. Also they don't need any batteries (the click generates the power, like with a piezo lighter). I had a few very old modules laying around, so while being sick at home with no energy to actually do something useful I just started designing an adapter frame (they didn't change the form factor) that perfectly fits into the existing light switches (Schneider Electric Merten) in my flat. Installation is very simple, just pop of the original rocker cover, insert the adapter, push in an EnOcean module and put on the two new rocker covers (todo: also design a fitting single-rocker cover).

This also comes with the very nice benefit of being able to pull out the adapter without requiring any tools and just operating the original light switch to reliably turn off power to a light fixture.