8-Step Arduino Sequencer

[fredrik]

There’s a diode from the USB power to the Arduino’s internal 5V rail, so you’ll get a slightly lower supply voltage and max signal level than if you use the correct voltages on the other supply pins, but the circuit should still work.

See here for a bit more on the voltage drops you can expect on the different supply inputs:

Design glitches: Arduino Nano supply voltage

(thought I’d collect my nano supply notes in one place to make it easier to link to) A common design glitch in circuits that use an Arduino Nano is to connect regulated 5 V to the VIN pin instead of the +5V pin. This results in the Arduino running at a lower internal supply voltage, often 4 V or below, which may be a problem if the design depends on analog inputs or digital output levels. Voltages below 4.5 V are also out of spec for the 16 MHz clock used by the Nano. Details below, but TL;DR …