Wow, great idea!Boot dryer blowing air only (no heat), but runs at about 1.5W (.3A, 5V) on a USB so can run off a battery pack or other charging device. Added an optional online switch.
Saw similar online for $90 and figured I could make my own simply enough. About an hour in CAD, 3d printer, $15 buying some fans and a switch on Amazon and 10 minutes splicing wires. Fun project to play, not sure how useful.