So this is my first instructable, hope it is usefull.
I was wondering for quite a while how could I build my own coffee heater, for the following reasons:
- I usually bring my coffe to my desktop (not the virtual one), and while I am coding or something it gets colder and colder, sometimes needing replacement (even my old Ni-Cd have a greater dutty cycle);
- Lots of power available through unused USB ports, I have 8 and use only 2 or 3 (think green);
- Usb heaters are cheap and easy to find, but I needed to build one from scratch to satisfy my ego (and impress my friends);
- I have lots and lots of scratch at home, needed to find a way to use them instead of just throwing out (think green, recycle, reuse reduce)
- and, at last but not least, I found someone who actually did it, with the math behind ( check this link ).
This is a prototype! - I actually built it, plugged to one of my USB and felt it going hot. The USB port still runs normally, no power or caffeine issues. But, as you'll see, it is not yet finished, no casing, no ZIF socket, no way to prevent the mug from dropping. I already have some ideas for an improved second version, comments and suggestions are welcome.