Making a sliding mechanism

i made it! Now i have to cable it correctly inside the box and install in i't final position.

Regarding the cable i have a question: since i already bought an Arduino NANO for this specific job is there a way to use the 12v input from the power source in parallel to power up the 5v usb?
There are already step down Dc 12v-5v but i can't find it to make my own

VIDEO - https://streamable.com/uhcf3