Maybe a bit optimistic but I don’t think it’d be to hard. Most devices already use pretty standard components, a microwave for example would have “something” t

Maybe a bit optimistic but I don’t think it’d be to hard. Most devices already use pretty standard components, a microwave for example would have “something” to switch the thing on and off. It might be a solid state relay or something like that. Maybe it has multiple, one to control the fan, light, motor to turn the things around, and the thing that emits the microwaves. But once you figure out what signal is needed to start those (a bit of intuition and a multimeter might suffice) you are off to the races! One you open a few house appliances it’s easy to see how they optimized for cost, so you seldom find fancy protocols or components unless they are absolutely necessary. In a toaster over for example, you might find a temperature sensor and it would likely take a bit of fever engineering to calibrate the temperature to the voltage output (I’m assuming that is a cheap analog sensor instead of something that spits a digital I2C signal for example). So yeah! It shouldn’t be too hard to hack your devices :-)