Schematic for my useless box (first project)

[Grumpy_Mike]

@Paul_B

You do not need to connect the switch to both 5 V and ground. You connect it to ground, and use INPUT_PULLUP mode on that Nano pin. In most cases, the 10k resistor is quite unnecessary.

You have not heeded this have you?

Also why not make the power switch to the whole thing the switch the Arm turns off

@spirale

all the useless boxes that I have seen use pin D2 with the interrupt mode.

So you have been seeing a lot of useless circuits then, there is no need to use interrupts in this system.