Gadget Freak Case #273: A Better Coffee Mug Warmer

Most of the coffee mug warmers available in the market utilize resistive heating. These warmers can be used with ceramic mugs or outer-body stainless steel mugs, but they aren't suitable for stainless-steel mugs that use a plastic outer cover for insulation.

Furthermore, resistive heating warmers are inefficient; most of the heat generated by the heating element is lost in the environment rather than warming coffee. A coffee mug warmer employing induction heating can target stainless steel mugs with or without the outer plastic cover. The mugs with the outer plastic cover are highly efficient, as there is less chance for heat-escape. An RF generator is connected to a coil, which creates oscillating magnetic field around the coil. A stainless-steel coffee mug, if placed on top of the coil or brought in close proximity to the coil, will induce eddy current in the stainless steel body - causing the generation of heat. Coffee put inside the mug will be kept warm or heated according to individual's test. The temperature can be controlled by controlling the current in the coil.

Download the full build instructions here.

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