Where to put unused Arduino pins?

Question

Arduino

I'm building a useless device on an arduino nano. In order for the pins not to catch interference, I need to transfer all the pins to the output and pull them to the ground through a 4.7 kΩ resistor. This seems to be understandable. But, if suddenly I want to connect via USB and watch the graph via Serial, then pins D1, D0 can no longer be touched. I want to split the board, but I don't know how to get around this problem.

Answer 1

Jumpers.
And so, in general, interference will not be caught very much if the same serial or something else is seen in the air or is drowned out by built-in suspenders. Well, if it's not a microwave controller

Answer 2

The pins of the Arduino microcontroller do not catch interference, therefore, by default, they are in the Hi-Z state. And the input resistance is about 1 MΩ. Such a hindrance can be a direct hit by lightning, for example.

Answer 3

By default, the Atmega pins are set to input and this is correct. Think about what will happen if an unused pin configured as an output shorts to ground.
Of course, there are interferences at unused inputs, but they do not affect the operation of the MK in any way.

Answer 4

There is no need to put them anywhere, just forget about their existence.
Of course, you don’t need to try to close them to something or do something else with them.