- Tue Feb 24, 2009 12:30 am
I wouldn't try to have one device that could keep beverages hot OR cold. There is such a thing as a mug warmer to keep beverages warm, though they don't have temperature controls. I saw one at a drug store for 4 or 5 dollars. I think I also recall instructions on instructables.com for making your own USB powered mug warmer. I often see potpourri or gravy warmers in thrift stores for $2-$5, if you can find a mug to fit in one of those (maybe in some water), that might work. I just submitted an idea for a plug-in thermostat switch with a wireless sensor idea. If someone ever makes it, you could use it with another appliance to keep it from heating a beverage too much.
To keep beverages cold get some reusable ice cubes. They are little plastic shapes filled with water that you freeze in the freezer.