The Arduino reads the state of the turn signal switches, and if they flick on momentarily it changes the pin from an input to an output and brings it high for three seconds.

This makes for 20 io points needed. Two more than the pro micro has. Luckily the gear lever only needs 1 of the 2 positions to be connected to act like a standard switch. That left one missing input ...

Each led in both is connected in series with a 1kΩ resistor to limit current. One Leonard-Micro difference is with the ‘built-in’ led. In the Leonardo, an op-amp between the ATmega pin and the led ...

Inside each of these slinky felines is pretty much what you’d expect to find — 25 or so switches and an Arduino Pro Micro. Interestingly enough, the switches are all lever-action and not push ...