You just need an Arduino Pro Micro, some tact switches, and a section of WS2812 RGB LED strip. There’s an excellent chance you’ve already got some of that in the parts bin, which will make it ...

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 ...