If you're using the standard jumper wires with male pin on the end to make connections to the
board headers, you might take a bunch of them, cut them in half, and solder a small value resistor
in the leads, 220 to 330 ohms. Put some tape or tubing over the connections to isolate the bare
connections. Goes a long way towards protecting I/O pins from overvoltage and short-circuits.
I'll keep that in mind. I just happened to make a dumb wiring mistake.