Like xn1ch1’s application, my push-button is connected to the Vcc rail, with a pull-down resistor to 0V. Xn1ch1’s framework stayed the same, with my adaptations limited to altering the states of three ...

So long as the 0V rail is connected to the Arduino 0V rail, the positive rail can be any dc voltage – more or less that the Arduino, so great for 12V motors. And it is compatible with both 5V and 3V ...