I need to connect the following devices to an Arduino UNO board. The problem is that I run out of pins to be able to connect them all. Is there any way to do it?

  • ultrasonic sensor
  • yellow led
  • green led
  • red led
  • buzzer
  • keypad 4x4

I'm doing the project in Tinkercad

In the picture below I tried to do it, but I am missing 2 pins for the ultrasonic sensor trig and echo

enter image description here

  • 4
    You can use the analog pins as digital input / output pins.
    – cguk70
    May 15, 2022 at 9:00
  • Another option would be one of these: instructables.com/…
    – VE7JRO
    May 15, 2022 at 19:48

1 Answer 1


As cguck70 already stated in the comments: The pins A0 to A5 can be analog input pins, but they can also be normal digital input/output pins. You can use them to your liking, just like any other digital input/output.

So just connect two of these pins to your ultrasonic sensor and use the pin names A0, A1 and so on in your code.

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