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Gadget Freak Case #273: A Better Coffee Mug Warmer

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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As always, Gadget Freak is brought to you by Allied Electronics and Design News. You can recreate Sajjad Haidar's gadget using the Allied parts list below.





Amt Value Parts Description Allied Part #
1 IRS2153 IC H-Bridge, MOSFET Driver, Oscillator 70017317
1 0.01uF CT Capacitor 70195788
2 0.1uF C1, C2 Capacitor 70195939
1 1.8k R1 Resistor 70024412
1 100k RT1 Potentiometer  70154227 
2 100uF C4, C5 Polarized Capacitor 70187364
1 1N5251B D1 Zener Diode 70061648
1 1k RT2 Resistor 70522113
1 30uF C3 Capacitor 70233336
1 4.7k R2 Resistor 70183451
1 5 uF C Capacitor 70233333
1 7uH L1 Toroidal Ferrite Core  70065384
2 IRFP150NPBF Q1, Q2 N-Channel MOS FET 70017034
1 TIP29C Q3 NPN Transistor 70013794
  24 V ZPSA60-24 Power Supply 70177449
1 TH-K-1-0-5   Thermocouple 70209691
1     Box 70148733
1     Copper Clad Board: 5” x 3” 70125831 
4     Banana plug 70090314
4     Banana Jack 70090206
2     Terminal 70054422
2     Heat sink 70115147 
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