[TeMPOraL]

This is literally what currently prevents me from doing DIY IoT projects at home. I'm not proficient enough in hardware to build battery-powered items, and I'm scared of leaving unattended anything I built that's powered off a wall wart.

[elvecinodeabajo]

To loss the fear just experiment with some safety and take measurments. You can let plugged a new project during some hours to look if it makes nasty things or not.

Anyway, I really encourage you to doing DIY projects at home. Most of them work in low voltages between 5 and 3.3V, risks are close to nothing.