@m26872 said in Encapsulated transformers instead of traditional switching power supplies like Hi-Link: for me the sunny season is too short. I havn't yet tried to use solar batteries in winter so maybe I have the same problems (despite the fact that I'm living 3 degrees south of you), but I have backup solution for very cloudy winter days - regular battery charger.

@jendrush said: Maybe small usb wall charger for 1,4$, and regulator from 5V to 3.3V for 0,1$ would be good solution? For some projects, using cheap chargers can be a good option. However, I'd open any such cheap charger and have a look before using it. Some appear to be acceptably designed, and some appear to be dangerous designs, from the teardowns. For example: http://www.righto.com/2012/10/a-dozen-usb-chargers-in-lab-apple-is.html He rated 2 out of the batch as downright dangerous. Even with one which appears to have a reasonable design with enough separation, I would not be poking around in the sensors or PCB while they are currently powered from 230V with a cheap charger. Unplug first. And if you need power for programming or testing, use your normal USB supply (eg: a laptop or a high quality power supply) or batteries. Maybe that's just me, but this seems like a reasonably easy additional precaution. Even if the PCB has good separation, the insulation between windings of a transformer could be marginal, for example. Most readers here probably already know this, just thought it was worth noting for anybody coming to this hobby more recently.