I was skiing in Colorado most of February and one simple thing I need is a way to heat up ski boots just to make them easier to get on.
Well its a pretty simple device for a car, a 12V plug and a couple modules that you slip into the boot. Inside each module are two 12 ohm 10W power resistors. Not much to go wrong right.
... Of course I didn't check it before going to Colorado and of course mine wasn't working. No tools there to fix it, wasn't the fuse.
Once I got back opened it up and a couple broken wires. Simple fix, but I decided to go ahead and add a couple LEDs so I could check operation next time before I go.
So no microprocessor and no programming, but satisfying to fix stuff rather than toss it.