I am thinking of building a sous-vide cooker using some kind of prebuild heater, controled via an AVR and temperature sensor like the LM35. There are a lot of references around using rice cookers, crook cookers or immersion heaters. As induction plates are getting cheaper, this might be a notable alternative, not only regarding reaction speed (they seem to be close to water cookers) and evenness of of the heating, but also the space for putting it away.
My main question might be a little bit physical, but I assume it is still better asked here: While electric resistance heater can just be switched on and off to regulate the temperature, I am not sure how well that works for induction, as there are strong magnetic fields involved. Does anyone have experience there? I could, instead of simply switching it on and off repeatedly, interface the control panel of the induction plate from the AVR (what would be the best way to do it? I feel the heater should be galvanically separated from the controlling circuit, so just soldering a transistor parallel to the switch doesn't sound like a good idea ...). But the lowest setting might still be too high, thus completely switching off the heat source might be necessary ...
Any experiences or suggestions?