Few years ago, I thought the same, that "old PC motherboards are under-appreciated", but trying to use them is just not very practical. The whole thing is so b

Few years ago, I thought the same, that "old PC motherboards are under-appreciated", but trying to use them is just not very practical. The whole thing is so big -- you need the PC itself (with huge PSU), plus a monitor, plus a keyboard. It takes a lot of power, too, and any sort of battery-powered device is out of the question. And the inputs are not even that well protected -- while the audio i/o is pretty robust, internal headers are not. Compare them to chinese Arduino clones or esp8266 board -- for $3, the price of a sandwich, you get a tiny board with excellent (or at least decent) documentation and lots of protected inputs and outputs. You can do hard real time too, with a bit of effort. And since all data/code is stored on your main laptop and PC you don't have to worry about backups or data loss from destroyed devices. (Note: if you want to support reusing old items, then raw atmega chips + serial-usb cables from old cell phones work as well, but require a bit more soldering) (Note: and if you really want to use old motherboards, don't forget about serial and parallel ports! Lots of pins, pretty protected, and very easy to programs)