I want to merge two projects: a "Don't touch your face" hat for Nano and a 7-segment 4-digit display for Uno. I tested both independently and they work. I added an RGB LED to the first, so I use 6 digital pins: 2 for the ultrasonic sensor, 1 for the buzzer, and 3 the RGB LED.
The Nano project takes 6 digital pins and no analog pins, leaving 4 digital pins and 8 analog pins. The Arduino Uno takes 12 digital pins. So I suppose that it's possible to replace the digital pins of the Uno with analog ones at the right voltage.
Even without the Nano project claiming 6 digital pins, the Nano only has 11 digital pins (D2-D12), not enough for a 7-segment 4-digit display. But I couldn't find a tutorial online on how to do so.
Is it possible to use a 7-segment 4-digit display on Arduino Nano?